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Oh it coo l it cool tall cool From Wikipedia, the free encyclopedia For other uses, see Life (disambiguation). "Life on Earth" redirects here. For other uses, see Life on Earth (disambiguation). Page semi-protected Life (Biota / Vitae / Eobionti)

Plants in the Rwenzori Mountains, Uganda Scientific classification e Domains and kingdoms Life on Earth: Non-cellular life (viruses) [note 1] Cellular life Bacteria Archaea Eukarya Protista Fungi Plantae Animalia Life is a characteristic that distinguishes objects that have signaling and self-sustaining processes from those that do not,[1][2] either because such functions have ceased (death), or else because they lack such functions and are classified as inanimate.[3][4] Biology is the science concerned with the study of life. Any contiguous living system is called an organism. Organisms undergo metabolism, maintain homeostasis, possess a capacity to grow, respond to stimuli, reproduce and, through natural selection, adapt to their environment in successive generations. More complex living organisms can communicate through various means.[1][5] A diverse array of living organisms can be found in the biosphere of Earth, and the properties common to these organisms—plants, animals, fungi, protists, archaea, and bacteria—are a carbon- and water-based cellular form with complex organization and heritable genetic information. Scientific evidence suggests that life began on Earth at least 3.5 billion years ago.[6][7] The earliest evidences for life on Earth are graphite found to be biogenic in 3.7 billion-year-old metasedimentary rocks discovered in Western Greenland[8] and microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia.[9][10] The mechanism by which life emerged on Earth is unknown, although many hypotheses have been formulated. Since then, life has evolved into a wide variety of forms, which biologists have classified into a hierarchy of taxa. Life can survive and thrive in a wide range of conditions. Though the existence of life is confirmed only on the planet Earth, many scientists think that extraterrestrial life is not only plausible, but probable or even inevitable.[11][12] Other planets and moons in the Solar System have been examined for evidence of having once supported simple life, and projects such as SETI have attempted to detect radio transmissions from possible alien civilizations. According to the panspermia hypothesis, microscopic life exists throughout the Universe, and is distributed by meteoroids, asteroids and planetoids.[13] The meaning of life—its significance, origin, purpose, and ultimate fate—is a central concept and question in philosophy and religion. Both philosophy and religion have offered interpretations as to how life relates to existence and consciousness, and on related issues such as life stance, purpose, conception of a god or gods, a soul or an afterlife. Different cultures throughout history have had widely varying approaches to these issues. Contents [hide] 1 Early theories 1.1 Materialism 1.2 Hylomorphism 1.3 Vitalism 2 Definitions 2.1 Biology 2.2 Living systems theories 3 Origin 4 Conditions 4.1 Range of tolerance 5 Form and function 6 Classification 7 Extraterrestrial life 7.1 Research 8 Death 9 Artificial life 10 See also 11 Notes 12 References 13 Further reading 14 External links Early theories

Materialism

Plant growth in the Hoh Rainforest

Herds of zebra and impala gathering on the Maasai Mara plain

An aerial photo of microbial mats around the Grand Prismatic Spring of Yellowstone National Park Some of the earliest theories of life were materialist, holding that all that exists is matter, and that life is merely a complex form or arrangement of matter. Empedocles (430 BC) argued that every thing in the universe is made up of a combination of four eternal "elements" or "roots of all": earth, water, air, and fire. All change is explained by the arrangement and rearrangement of these four elements. The various forms of life are caused by an appropriate mixture of elements.[14] Democritus (460 BC) thought that the essential characteristic of life is having a soul (psyche). Like other ancient writers, he was attempting to explain what makes something a living thing. His explanation was that fiery atoms make a soul in exactly the same way atoms and void account for any other thing. He elaborates on fire because of the apparent connection between life and heat, and because fire moves.[15] Plato's world of eternal and unchanging Forms, imperfectly represented in matter by a divine Artisan, contrasts sharply with the various mechanistic Weltanschauungen, of which atomism was, by the fourth century at least, the most prominent... This debate persisted throughout the ancient world. Atomistic mechanism got a shot in the arm from Epicurus... while the Stoics adopted a divine teleology... The choice seems simple: either show how a structured, regular world could arise out of undirected processes, or inject intelligence into the system.[16] —R. J. Hankinson, Cause and Explanation in Ancient Greek Thought The mechanistic materialism that originated in ancient Greece was revived and revised by the French philosopher René Descartes, who held that animals and humans were assemblages of parts that together functioned as a machine. In the 19th century, the advances in cell theory in biological science encouraged this view. The evolutionary theory of Charles Darwin (1859) is a mechanistic explanation for the origin of species by means of natural selection.[17] Hylomorphism Hylomorphism is a theory (originating with Aristotle (322 BC)) that all things are a combination of matter and form. Biology was one of his main interests, and there is extensive biological material in his extant writings. In this view, all things in the material universe have both matter and form, and the form of a living thing is its soul (Greek psyche, Latin anima). There are three kinds of souls: the vegetative soul of plants, which causes them to grow and decay and nourish themselves, but does not cause motion and sensation; the animal soul, which causes animals to move and feel; and the rational soul, which is the source of consciousness and reasoning, which (Aristotle believed) is found only in man.[18] Each higher soul has all the attributes of the lower one. Aristotle believed that while matter can exist without form, form cannot exist without matter, and therefore the soul cannot exist without the body.[19] This account is consistent with teleological explanations of life, which account for phenomena in terms of purpose or goal-directedness. Thus, the whiteness of the polar bear's coat is explained by its purpose of camouflage. The direction of causality (from the future to the past) is in contradiction with the scientific evidence for natural selection, which explains the consequence in terms of a prior cause. Biological features are explained not by looking at future optimal results, but by looking at the past evolutionary history of a species, which led to the natural selection of the features in question.[20] Vitalism Vitalism is the belief that the life-principle is non-material. This originated with Stahl (17th century), and held sway until the middle of the 19th century. It appealed to philosophers such as Henri Bergson, Nietzsche, Wilhelm Dilthey,[21] anatomists like Bichat, and chemists like Liebig.[22] Vitalism included the idea that there was a fundamental difference between organic and inorganic material, and the belief that organic material can only be derived from living things. This was disproved in 1828, when Friedrich Wöhler prepared urea from inorganic materials.[23] This Wöhler synthesis is considered the starting point of modern organic chemistry. It is of historical significance because for the first time an organic compound was produced from inorganic reactants.[22] During the 1850s, Helmholtz, anticipated by Mayer, demonstrated that no energy is lost in muscle movement, suggesting that there were no "vital forces" necessary to move a muscle.[24] These results led to the abandonment of scientific interest in vitalistic theories, although the belief lingered on in pseudoscientific theories such as homeopathy, which interprets diseases and sickness as caused by disturbances in a hypothetical vital force or life force.[25] Definitions

It is a challenge for scientists and philosophers to define life in unequivocal terms.[26][27][28] This is difficult partly because life is a process, not a pure substance.[29][30] Any definition must be sufficiently broad to encompass all life with which we are familiar, and must be sufficiently general to include life that may be fundamentally different from life on Earth.[31][32][33] Biology Since there is no unequivocal definition of life, the current understanding is descriptive. Life is considered a characteristic of organisms that exhibit all or most of the following characteristics or traits:[32][34][35] Homeostasis: Regulation of the internal environment to maintain a constant state; for example, electrolyte concentration or sweating to reduce temperature. Organization: Being structurally composed of one or more cells — the basic units of life. Metabolism: Transformation of energy by converting chemicals and energy into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life. Growth: Maintenance of a higher rate of anabolism than catabolism. A growing organism increases in size in all of its parts, rather than simply accumulating matter. Adaptation: The ability to change over time in response to the environment. This ability is fundamental to the process of evolution and is determined by the organism's heredity, diet, and external factors. Response to stimuli: A response can take many forms, from the contraction of a unicellular organism to external chemicals, to complex reactions involving all the senses of multicellular organisms. A response is often expressed by motion; for example, the leaves of a plant turning toward the sun (phototropism), and chemotaxis. Reproduction: The ability to produce new individual organisms, either asexually from a single parent organism, or sexually from two parent organisms. These complex processes, called physiological functions, have underlying physical and chemical bases, as well as signaling and control mechanisms that are essential to maintaining life. Alternatives See also: Entropy and life To reflect the minimum phenomena required, other biological definitions of life have been proposed,[36] many of these are based upon chemical systems. Biophysicists have commented that living things function on negative entropy.[37][38] In other words, living processes can be viewed as a delay of the spontaneous diffusion or dispersion of the internal energy of biological molecules towards more potential microstates.[39] In more detail, according to physicists such as John Bernal, Erwin Schrödinger, Eugene Wigner, and John Avery, life is a member of the class of phenomena that are open or continuous systems able to decrease their internal entropy at the expense of substances or free energy taken in from the environment and subsequently rejected in a degraded form.[40][41][42] At a higher level, living beings are thermodynamic systems that have an organized molecular structure.[39] That is, life is matter that can reproduce itself and evolve as survival dictates.[43][44] Hence, life is a self-sustained chemical system capable of undergoing Darwinian evolution.[45] Others take a systemic viewpoint that does not necessarily depend on molecular chemistry. One systemic definition of life is that living things are self-organizing and autopoietic (self-producing). Variations of this definition include Stuart Kauffman's definition as an autonomous agent or a multi-agent system capable of reproducing itself or themselves, and of completing at least one thermodynamic work cycle.[46] Life can be modeled as a network of inferior negative feedbacks of regulatory mechanisms subordinated to a superior positive feedback formed by the potential of expansion and reproduction.[47] Alternatively, life can be said to consist of things with the capacity for metabolism and motion,[32] or that life is self-reproduction "with variations"[48][49] or "with an error rate below the sustainability threshold."[49] Viruses

Electron micrograph of adenovirus with a cartoon to demonstrate its icosahedral structure Viruses are most often considered replicators rather than forms of life. They have been described as "organisms at the edge of life,"[50] since they possess genes, evolve by natural selection,[51][52] and replicate by creating multiple copies of themselves through self-assembly. However, viruses do not metabolize and they require a host cell to make new products. Virus self-assembly within host cells has implications for the study of the origin of life, as it may support the hypothesis that life could have started as self-assembling organic molecules.[53][54][55] Living systems theories The idea that the Earth is alive is found in philosophy and religion, but the first scientific discussion of it was by the Scottish scientist James Hutton. In 1785, he stated that the Earth was a superorganism and that its proper study should be physiology. Hutton is considered the father of geology, but his idea of a living Earth was forgotten in the intense reductionism of the 19th century.[56] The Gaia hypothesis, proposed in the 1960s by scientist James Lovelock,[57][58] suggests that life on Earth functions as a single organism that defines and maintains environmental conditions necessary for its survival.[59] The first attempt at a general living systems theory for explaining the nature of life was in 1978, by American biologist James Grier Miller.[60] Such a general theory, arising out of the ecological and biological sciences, attempts to map general principles for how all living systems work. Instead of examining phenomena by attempting to break things down into component parts, a general living systems theory explores phenomena in terms of dynamic patterns of the relationships of organisms with their environment.[61] Robert Rosen (1991) built on this by defining a system component as "a unit of organization; a part with a function, i.e., a definite relation between part and whole." From this and other starting concepts, he developed a "relational theory of systems" that attempts to explain the special properties of life. Specifically, he identified the "nonfractionability of components in an organism" as the fundamental difference between living systems and "biological machines."[62] A systems view of life treats environmental fluxes and biological fluxes together as a "reciprocity of influence",[63] and a reciprocal relation with environment is arguably as important for understanding life as it is for understanding ecosystems. As Harold J. Morowitz (1992) explains it, life is a property of an ecological system rather than a single organism or species.[64] He argues that an ecosystemic definition of life is preferable to a strictly biochemical or physical one. Robert Ulanowicz (2009) highlights mutualism as the key to understand the systemic, order-generating behavior of life and ecosystems.[65] Complex systems biology (CSB) is a field of science that studies the emergence of complexity in functional organisms from the viewpoint of dynamic systems theory.[66] The latter is often called also systems biology and aims to understand the most fundamental aspects of life. A closely related approach to CSB and systems biology, called relational biology,[67][68] is concerned mainly with understanding life processes in terms of the most important relations, and categories of such relations among the essential functional components of organisms; for multicellular organisms, this has been defined as "categorical biology", or a model representation of organisms as a category theory of biological relations, and also an algebraic topology of the functional organization of living organisms in terms of their dynamic, complex networks of metabolic, genetic, epigenetic processes and signaling pathways.[citation needed] It has also been argued that the evolution of order in living systems and certain physical systems obey a common fundamental principle termed the Darwinian dynamic.[69][70] The Darwinian dynamic was formulated by first considering how macroscopic order is generated in a simple non-biological system far from thermodynamic equilibrium, and then extending consideration to short, replicating RNA molecules. The underlying order generating process for both types of system was concluded to be basically similar.[71] Origin

Main article: Abiogenesis Evidence suggests that life on Earth has existed for about 3.7 billion years,[72] with the oldest traces of life found in fossils dating back 3.4 billion years.[73] In a National Institutes of Health study, the authors hypothesize that if biological complexity increased exponentially during evolution, life in the universe may have begun nearly 10 billion years ago[74][75] - billions of years before the Earth existed, suggesting that Earth was seeded by panspermia or directed panspermia. All known life forms share fundamental molecular mechanisms, reflecting their common descent; based on these observations, hypotheses on the origin of life attempt to find a mechanism explaining the formation of a universal common ancestor, from simple organic molecules via pre-cellular life to protocells and metabolism. Models have been divided into "genes-first" and "metabolism-first" categories, but a recent trend is the emergence of hybrid models that combine both categories.[76] There is no current scientific consensus as to how life originated. However, most accepted scientific models build on the following observations: The Miller-Urey experiment, and the work of Sidney Fox, show that conditions on the primitive Earth favored chemical reactions that synthesize amino acids and other organic compounds from inorganic precursors.[77] Phospholipids spontaneously form lipid bilayers, the basic structure of a cell membrane. Living organisms synthesize proteins, which are polymers of amino acids using instructions encoded by deoxyribonucleic acid (DNA). Protein synthesis entails intermediary ribonucleic acid (RNA) polymers. One possibility for how life began is that genes originated first, followed by proteins;[78] the alternative being that proteins came first and then genes.[79] However, since genes and proteins are both required to produce the other, the problem of considering which came first is like that of the chicken or the egg. Most scientists have adopted the hypothesis that because of this, it is unlikely that genes and proteins arose independently.[80] Therefore, a possibility, first suggested by Francis Crick,[81] is that the first life was based on RNA,[80] which has the DNA-like properties of information storage and the catalytic properties of some proteins. This is called the RNA world hypothesis, and it is supported by the observation that many of the most critical components of cells (those that evolve the slowest) are composed mostly or entirely of RNA. Also, many critical cofactors (ATP, Acetyl-CoA, NADH, etc.) are either nucleotides or substances clearly related to them. The catalytic properties of RNA had not yet been demonstrated when the hypothesis was first proposed,[82] but they were confirmed by Thomas Cech in 1986.[83] One issue with the RNA world hypothesis is that synthesis of RNA from simple inorganic precursors is more difficult than for other organic molecules. One reason for this is that RNA precursors are very stable and react with each other very slowly under ambient conditions, and it has also been proposed that living organisms consisted of other molecules before RNA.[84] However, the successful synthesis of certain RNA molecules under the conditions that existed prior to life on Earth has been achieved by adding alternative precursors in a specified order with the precursor phosphate present throughout the reaction.[85] This study makes the RNA world hypothesis more plausible.[86] Geological findings in 2013 showed that reactive phosphorus species (like phosphite) were in abundance in the ocean before 3.5 Ga, and that Schreibersite easily reacts with aqueous glycerol to generate phosphite and glycerol 3-phosphate.[87] It is hypothesized that Schreibersite-containing meteorites from the Late Heavy Bombardment could have provided early reduced phosphorus, which could react with prebiotic organic molecules to form phosphorylated biomolecules, like RNA. In 2009, experiments demonstrated Darwinian evolution of a two-component system of RNA enzymes (ribozymes) in vitro.[88] The work was performed in the laboratory of Gerald Joyce, who stated, "This is the first example, outside of biology, of evolutionary adaptation in a molecular genetic system."[89] Prebiotic compounds may have extraterrestrial origin. NASA findings in 2011, based on studies with meteorites found on Earth, suggest DNA and RNA components (adenine, guanine and related organic molecules) may be formed in outer space.[90][91][92][93] Conditions

Cyanobacteria dramatically changed the composition of life forms on Earth by leading to the near-extinction of oxygen-intolerant organisms. The diversity of life on Earth is a result of the dynamic interplay between genetic opportunity, metabolic capability, environmental challenges,[94] and symbiosis.[95][96][97] For most of its existence, Earth's habitable environment has been dominated by microorganisms and subjected to their metabolism and evolution. As a consequence of these microbial activities, the physical-chemical environment on Earth has been changing on a geologic time scale, thereby affecting the path of evolution of subsequent life.[94] For example, the release of molecular oxygen by cyanobacteria as a by-product of photosynthesis induced global changes in the Earth's environment. Since oxygen was toxic to most life on Earth at the time, this posed novel evolutionary challenges, and ultimately resulted in the formation of our planet's major animal and plant species. This interplay between organisms and their environment is an inherent feature of living systems.[94] All life forms require certain core chemical elements needed for biochemical functioning. These include carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur—the elemental macronutrients for all organisms[98]—often represented by the acronym CHNOPS. Together these make up nucleic acids, proteins and lipids, the bulk of living matter. Five of these six elements comprise the chemical components of DNA, the exception being sulfur. The latter is a component of the amino acids cysteine and methionine. The most biologically abundant of these elements is carbon, which has the desirable attribute of forming multiple, stable covalent bonds. This allows carbon-based (organic) molecules to form an immense variety of chemical arrangements.[99] Alternative hypothetical types of biochemistry have been proposed that eliminate one or more of these elements, swap out an element for one not on the list, or change required chiralities or other chemical properties.[100][101] Range of tolerance The inert components of an ecosystem are the physical and chemical factors necessary for life — energy (sunlight or chemical energy), water, temperature, atmosphere, gravity, nutrients, and ultraviolet solar radiation protection.[102] In most ecosystems, the conditions vary during the day and from one season to the next. To live in most ecosystems, then, organisms must be able to survive a range of conditions, called the "range of tolerance."[103] Outside that are the "zones of physiological stress," where the survival and reproduction are possible but not optimal. Beyond these zones are the "zones of intolerance," where survival and reproduction of that organism is unlikely or impossible. Organisms that have a wide range of tolerance are more widely distributed than organisms with a narrow range of tolerance.[103]

Deinococcus radiodurans is an extremophile that can resist extremes of cold, dehydration, vacuum, acid, and radiation exposure. To survive, selected microorganisms can assume forms that enable them to withstand freezing, complete desiccation, starvation, high levels of radiation exposure, and other physical or chemical challenges. These microorganisms may survive exposure to such conditions for weeks, months, years, or even centuries.[94] Extremophiles are microbial life forms that thrive outside the ranges where life is commonly found. They excel at exploiting uncommon sources of energy. While all organisms are composed of nearly identical molecules, evolution has enabled such microbes to cope with this wide range of physical and chemical conditions. Characterization of the structure and metabolic diversity of microbial communities in such extreme environments is ongoing.[104] On 17 March 2013, researchers reported data that suggested microbial life forms thrive in the Mariana Trench, the deepest spot on the Earth.[105][106] Other researchers reported related studies that microbes thrive inside rocks up to 1900 feet below the sea floor under 8500 feet of ocean off the coast of the northwestern United States.[105][107] According to one of the researchers,"You can find microbes everywhere — they're extremely adaptable to conditions, and survive wherever they are."[105] Investigation of the tenacity and versatility of life on Earth, as well as an understanding of the molecular systems that some organisms utilize to survive such extremes, is important for the search for life beyond Earth.[94] In April 2012, scientists reported that lichen could survive for a month in a simulated Martian environment.[108][109] Form and function

Cells are the basic unit of structure in every living thing, and all cells arise from pre-existing cells by division. Cell theory was formulated by Henri Dutrochet, Theodor Schwann, Rudolf Virchow and others during the early nineteenth century, and subsequently became widely accepted.[110] The activity of an organism depends on the total activity of its cells, with energy flow occurring within and between them. Cells contain hereditary information that is carried forward as a genetic code during cell division.[111] There are two primary types of cells. Prokaryotes lack a nucleus and other membrane-bound organelles, although they have circular DNA and ribosomes. Bacteria and Archaea are two domains of prokaryotes. The other primary type of cells are the eukaryotes, which have distinct nuclei bound by a nuclear membrane and membrane-bound organelles, including mitochondria, chloroplasts, lysosomes, rough and smooth endoplasmic reticulum, and vacuoles. In addition, they possess organized chromosomes that store genetic material. All species of large complex organisms are eukaryotes, including animals, plants and fungi, though most species of eukaryote are protist microorganisms.[112] The conventional model is that eukaryotes evolved from prokaryotes, with the main organelles of the eukaryotes forming through endosymbiosis between bacteria and the progenitor eukaryotic cell.[113] The molecular mechanisms of cell biology are based on proteins. Most of these are synthesized by the ribosomes through an enzyme-catalyzed process called protein biosynthesis. A sequence of amino acids is assembled and joined together based upon gene expression of the cell's nucleic acid.[114] In eukaryotic cells, these proteins may then be transported and processed through the Golgi apparatus in preparation for dispatch to their destination. Cells reproduce through a process of cell division in which the parent cell divides into two or more daughter cells. For prokaryotes, cell division occurs through a process of fission in which the DNA is replicated, then the two copies are attached to parts of the cell membrane. In eukaryotes, a more complex process of mitosis is followed. However, the end result is the same; the resulting cell copies are identical to each other and to the original cell (except for mutations), and both are capable of further division following an interphase period.[115] Multicellular organisms may have first evolved through the formation of colonies of like cells. These cells can form group organisms through cell adhesion. The individual members of a colony are capable of surviving on their own, whereas the members of a true multi-cellular organism have developed specialties, making them dependent on the remainder of the organism for survival. Such organisms are formed clonally or from a single germ cell that is capable of forming the various specialized cells that form the adult organism. This specialization allows multicellular organisms to exploit resources more efficiently than single cells.[116] Cells have evolved methods to perceive and respond to their microenvironment, thereby enhancing their adaptability. Cell signaling coordinates cellular activities, and hence governs the basic functions of multicellular organisms. Signaling between cells can occur through direct cell contact using juxtacrine signalling, or indirectly through the exchange of agents as in the endocrine system. In more complex organisms, coordination of activities can occur through a dedicated nervous system.[117] Classification

Main article: Biological classification

The hierarchy of biological classification's eight major taxonomic ranks. Life is divided into domains, which are subdivided into further groups. Intermediate minor rankings are not shown. The first known attempt to classify organisms was conducted by the Greek philosopher Aristotle (384–322 BC), who classified all living organisms known at that time as either a plant or an animal, based mainly on their ability to move. He also distinguished animals with blood from animals without blood (or at least without red blood), which can be compared with the concepts of vertebrates and invertebrates respectively, and divided the blooded animals into five groups: viviparous quadrupeds (mammals), oviparous quadrupeds (reptiles and amphibians), birds, fishes and whales. The bloodless animals were also divided into five groups: cephalopods, crustaceans, insects (which included the spiders, scorpions, and centipedes, in addition to what we define as insects today), shelled animals (such as most molluscs and echinoderms) and "zoophytes." Though Aristotle's work in zoology was not without errors, it was the grandest biological synthesis of the time and remained the ultimate authority for many centuries after his death.[118] The exploration of the American continent revealed large numbers of new plants and animals that needed descriptions and classification. In the latter part of the 16th century and the beginning of the 17th, careful study of animals commenced and was gradually extended until it formed a sufficient body of knowledge to serve as an anatomical basis for classification. In the late 1740s, Carolus Linnaeus introduced his system of binomial nomenclature for the classification of species.[119] Linnaeus attempted to improve the composition and reduce the length of the previously used many-worded names by abolishing unnecessary rhetoric, introducing new descriptive terms and precisely defining their meaning. By consistently using this system, Linnaeus separated nomenclature from taxonomy. The fungi were originally treated as plants. For a short period Linnaeus had classified them in the taxon Vermes in Animalia, but later placed them back in Plantae. Copeland classified the Fungi in his Protoctista, thus partially avoiding the problem but acknowledging their special status.[120] The problem was eventually solved by Whittaker, when he gave them their own kingdom in his five-kingdom system. Evolutionary history shows that the fungi are more closely related to animals than to plants.[121] As new discoveries enabled detailed study of cells and microorganisms, new groups of life were revealed, and the fields of cell biology and microbiology were created. These new organisms were originally described separately in protozoa as animals and protophyta/thallophyta as plants, but were united by Haeckel in the kingdom Protista; later, the prokaryotes were split off in the kingdom Monera, which would eventually be divided into two separate groups, the Bacteria and the Archaea. This led to the six-kingdom system and eventually to the current three-domain system, which is based on evolutionary relationships.[122] However, the classification of eukaryotes, especially of protists, is still controversial.[123] As microbiology, molecular biology and virology developed, non-cellular reproducing agents were discovered, such as viruses and viroids. Whether these are considered alive has been a matter of debate; viruses lack characteristics of life such as cell membranes, metabolism and the ability to grow or respond to their environments. Viruses can still be classed into "species" based on their biology and genetics, but many aspects of such a classification remain controversial.[124] In the 1960s a trend called cladistics emerged, arranging taxa based on clades in an evolutionary or phylogenetic tree.[125] Linnaeus 1735[126] Haeckel 1866[127] Chatton 1925[128] Copeland 1938[120] Whittaker 1969[129] Woese et al. 1990[122] Cavalier-Smith 1998[130] 2 kingdoms 3 kingdoms 2 empires 4 kingdoms 5 kingdoms 3 domains 6 kingdoms (not treated) Protista Prokaryota Monera Monera Bacteria Bacteria Archaea Eukaryota Protoctista Protista Eucarya Protozoa Chromista Vegetabilia Plantae Plantae Plantae Plantae Fungi Fungi Animalia Animalia Animalia Animalia Animalia Main article: Kingdom (biology)#Summary Extraterrestrial life

Main articles: Extraterrestrial life, Astrobiology, Astroecology , and Life in the solar system

Panspermia hypothesis showing bacteria being carried to Earth by a comet Earth is the only planet known to harbor life. Other locations within the Solar System that may host life include subsurface Mars, the atmosphere of Venus,[131] and subsurface oceans on some of the moons of the gas giant planets.[132] The Drake equation, which predicts the number of extraterrestrial civilizations in our galaxy with which we might come in contact, has been used to discuss the probability of life elsewhere, but many of the variables in this equation are difficult to estimate.[133] The region around a main sequence star that could support Earth-like life on an Earth-like planet is known as the habitable zone. The inner and outer radii of this zone vary with the luminosity of the star, as does the time interval during which the zone survives. Stars more massive than the Sun have a larger habitable zone, but remain on the main sequence for a shorter time interval. Small red dwarf stars have the opposite problem, with a smaller habitable zone that is subject to higher levels of magnetic activity and the effects of tidal locking from close orbits. Hence, stars in the intermediate mass range such as the Sun may have a greater likelihood for Earth-like life to develop.[134] The location of the star within a galaxy may also have an impact on the likelihood of life forming. Stars in regions with a greater abundance of heavier elements that can form planets, in combination with a low rate of potentially habitat-damaging supernova events, are predicted to have a higher probability of hosting planets with complex life.[135] Panspermia, also called exogenesis, is the hypothesis that life originated elsewhere in the universe and subsequently transferred to Earth in the form of spores via meteorites, comets, or cosmic dust. Conversely, terrestrial life may be seeded in other solar systems through directed panspermia, to secure and expand some terrestrial life forms.[29][30][33] Astroecology experiments with meteorites show that Martian asteroids and cometary materials are rich in inorganic elements and may be fertile soils for microbial, algal and plant life, for past and future life in our and other solar systems.[136] Research See also: List of molecules in interstellar space In 2004, scientists reported[137] detecting the spectral signatures of anthracene and pyrene in the ultraviolet light emitted by the Red Rectangle nebula (no other such complex molecules had ever been found before in outer space). This discovery was considered a confirmation of a hypothesis that as nebulae of the same type as the Red Rectangle approach the ends of their lives, convection currents cause carbon and hydrogen in the nebulae's core to get caught in stellar winds, and radiate outward.[138] As they cool, the atoms supposedly bond to each other in various ways and eventually form particles of a million or more atoms. The scientists inferred[137] that since they discovered polycyclic aromatic hydrocarbons (PAHs) — which may have been vital in the formation of early life on Earth — in a nebula, by necessity they must originate in nebulae.[138] In August 2009, NASA scientists identified one of the fundamental chemical building-blocks of life (the amino acid glycine) in a comet for the first time.[139] In 2010, fullerenes (or "buckyballs") were detected in nebulae.[140] Fullerenes have been implicated in the origin of life; according to astronomer Letizia Stanghellini, "It's possible that buckyballs from outer space provided seeds for life on Earth."[141] In August 2011, findings by NASA, based on studies of meteorites found on Earth, suggests DNA and RNA components (adenine, guanine and related organic molecules), building blocks for life as we know it, may be formed extraterrestrially in outer space.[90][91][92] In October 2011, scientists found using spectroscopy that cosmic dust contains complex organic matter ("amorphous organic solids with a mixed aromatic-aliphatic structure") that could be created naturally, and rapidly, by stars.[142][143][144] The compounds are so complex that their chemical structures resemble the makeup of coal and petroleum; such chemical complexity was previously thought to arise only from living organisms.[142] These observations suggest that organic compounds introduced on Earth by interstellar dust particles could serve as basic ingredients for life due to their surface-catalytic activities.[93][145] One of the scientists suggested that these compounds may have been related to the development of life on Earth and said that, "If this is the case, life on Earth may have had an easier time getting started as these organics can serve as basic ingredients for life."[142] In August 2012, astronomers at Copenhagen University reported the detection of a specific sugar molecule, glycolaldehyde, in a distant star system. The molecule was found around the protostellar binary IRAS 16293-2422, which is located 400 light years from Earth.[146][147] Glycolaldehyde is needed to form ribonucleic acid, or RNA, which is similar in function to DNA. This finding suggests that complex organic molecules may form in stellar systems prior to the formation of planets, eventually arriving on young planets early in their formation.[148] In September 2012, NASA scientists reported that polycyclic aromatic hydrocarbons (PAHs), subjected to interstellar medium (ISM) conditions, are transformed, through hydrogenation, oxygenation and hydroxylation, to more complex organics - "a step along the path toward amino acids and nucleotides, the raw materials of proteins and DNA, respectively".[149][150] Further, as a result of these transformations, the PAHs lose their spectroscopic signature which could be one of the reasons "for the lack of PAH detection in interstellar ice grains, particularly the outer regions of cold, dense clouds or the upper molecular layers of protoplanetary disks."[149][150] In June 2013, polycyclic aromatic hydrocarbons (PAHs) were detected in the upper atmosphere of Titan, the largest moon of the planet Saturn.[151] In 2013, the Atacama Large Millimeter Array (ALMA Project) confirmed that researchers have discovered an important pair of prebiotic molecules in the icy particles in interstellar space (ISM). The chemicals, found in a giant cloud of gas about 25,000 light-years from Earth in ISM, may be a precursor to a key component of DNA and the other may have a role in the formation of an important amino acid. Researchers found a molecule called cyanomethanimine, which produces adenine, one of the four nucleobases that form the “rungs” in the ladder-like structure of DNA. The other molecule, called ethanamine, is thought to play a role in forming alanine, one of the twenty amino acids in the genetic code. Previously, scientists thought such processes took place in the very tenuous gas between the stars. The new discoveries, however, suggest that the chemical formation sequences for these molecules occurred not in gas, but on the surfaces of ice grains in interstellar space.[152] NASA ALMA scientist Anthony Remijan stated that finding these molecules in an interstellar gas cloud means that important building blocks for DNA and amino acids can 'seed' newly formed planets with the chemical precursors for life.[153] In January 2014, NASA reported that current studies on the planet Mars by the Curiosity and Opportunity rovers will now be searching for evidence of ancient life, including a biosphere based on autotrophic, chemotrophic and/or chemolithoautotrophic microorganisms, as well as ancient water, including fluvio-lacustrine environments (plains related to ancient rivers or lakes) that may have been habitable.[154][155][156][157] The search for evidence of habitability, taphonomy (related to fossils), and organic carbon on the planet Mars is now a primary NASA objective.[154] Death

Main article: Death

Animal corpses, like this African buffalo, are recycled by the ecosystem, providing energy and nutrients for living creatures Death is the permanent termination of all vital functions or life processes in an organism or cell.[158][159] It can occur as a result of an accident, medical conditions, biological interaction, malnutrition, poisoning, senescence, or suicide. After death, the remains of an organism re-enter the biogeochemical cycle. Organisms may be consumed by a predator or a scavenger and leftover organic material may then be further decomposed by detritivores, organisms that recycle detritus, returning it to the environment for reuse in the food chain. One of the challenges in defining death is in distinguishing it from life. Death would seem to refer to either the moment life ends, or when the state that follows life begins.[159] However, determining when death has occurred requires drawing precise conceptual boundaries between life and death. This is problematic, however, because there is little consensus over how to define life. The nature of death has for millennia been a central concern of the world's religious traditions and of philosophical inquiry. Many religions maintain faith in either a kind of afterlife or reincarnation for the soul, or resurrection of the body at a later date. Extinction is the process by which a group of taxa or species dies out, reducing biodiversity.[160] The moment of extinction is generally considered the death of the last individual of that species. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively after a period of apparent absence. Species become extinct when they are no longer able to survive in changing habitat or against superior competition. In Earth's history, over 99% of all the species that have ever lived have gone extinct;[161] however, mass extinctions may have accelerated evolution by providing opportunities for new groups of organisms to diversify.[162] Fossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossil-containing rock formations and sedimentary layers (strata) is known as the fossil record. A preserved specimen is called a fossil if it is older than the arbitrary date of 10,000 years ago.[163] Hence, fossils range in age from the youngest at the start of the Holocene Epoch to the oldest from the Archaean Eon, up to 3.4 billion years old.[164][165] Artificial life

Main articles: Artificial life and Synthetic biology Artificial life is a field of study that examines systems related to life, its processes, and its evolution through simulations using computer models, robotics, and biochemistry.[166] The study of artificial life imitates traditional biology by recreating some aspects of biological phenomena. Scientists study the logic of living systems by creating artificial environments—seeking to understand the complex information processing that defines such systems. While life is, by definition, alive, artificial life is generally referred to as data confined to a digital environment and existence. Synthetic biology is a new area of biological research and technology that combines science and biological engineering. The common goal is the design and construction of new biological functions and systems not found in nature. Synthetic biology includes the broad redefinition and expansion of biotechnology, with the ultimate goals of being able to design and build engineered biological systems that process information, manipulate chemicals, fabricate materials and structures, produce energy, provide food, and maintain and enhance human health and our environment.[167] See also

Alpha taxonomy Astroecology Biological organisation Biosignature Chronobiology Conway's Game of Life Constructal law Evolutionary history of life Life on Mars Life skills Lists of organisms by population Meaning of life Non-cellular life Personal life Phylogenetics Quality of life Notes

Jump up ^ The 'evolution' of viruses and other similar forms is still uncertain. Therefore, this classification may be paraphyletic because cellular life might have evolved from non-cellular life, or polyphyletic because the most recent common ancestor might not be included. References

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Kauffman, Stuart. The Adjacent Possible: A Talk with Stuart Kauffman Seeding the Universe With Life Legacy Books, Washington D. C., 2000, ISBN 0-476-00330-X Walker, Martin G. LIFE! Why We Exist...And What We Must Do to Survive Dog Ear Publishing, 2006, ISBN 1-59858-243-7 Adrian Bejan, Sylvie Lorente, The constructal law and the evolution of design in nature, Physics of Life Reviews, Volume 8, Issue 3, October 2011, Pages 209-240, ISSN 1571-0645, [1] External links

Wikimedia Commons has media related to Tree of life. Wikiquote has a collection of quotations related to: Life Look up life or living in Wiktionary, the free dictionary. Wikispecies has information related to: The Taxonomy of Life Wikispecies – a free directory of life Resources for life in the Solar System and in galaxy, and the potential scope of life in the cosmological future "The Adjacent Possible: A Talk with Stuart Kauffman" Stanford Encyclopedia of Philosophy entry The Kingdoms of Life [show] v t e Elements of nature [show] v t e Hierarchy of life [show] v t e Evolutionary biology [show] v t e Taxonomic ranks [show] v t e Natural resources Categories: Biological systemsBiologyBiology terminologyLife Navigation menu Create accountLog inArticleTalkReadView sourceView history

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<poll> Life is a characteristic that distinguishes objects that have signaling and self-sustaining processes from those that do not,[1][2] either because such functions have ceased (death), or else because they lack such functions and are classified as inanimate.[3][4] Biology is the science concerned with the study of life. Any contiguous living system is called an organism. Organisms undergo metabolism, maintain homeostasis, possess a capacity to grow, respond to stimuli, reproduce and, through natural selection, adapt to their environment in successive generations. More complex living organisms can communicate through various means.[1][5] A diverse array of living organisms can be found in the biosphere of Earth, and the properties common to these organisms—plants, animals, fungi, protists, archaea, and bacteria—are a carbon- and water-based cellular form with complex organization and heritable genetic information. Scientific evidence suggests that life began on Earth at least 3.5 billion years ago.[6][7] The earliest evidences for life on Earth are graphite found to be biogenic in 3.7 billion-year-old metasedimentary rocks discovered in Western Greenland[8] and microbial mat fossils found in 3.48 billion-year-old sandstone discovered in Western Australia.[9][10] The mechanism by which life emerged on Earth is unknown, although many hypotheses have been formulated. Since then, life has evolved into a wide variety of forms, which biologists have classified into a hierarchy of taxa. Life can survive and thrive in a wide range of conditions. Though the existence of life is confirmed only on the planet Earth, many scientists think that extraterrestrial life is not only plausible, but probable or even inevitable.[11][12] Other planets and moons in the Solar System have been examined for evidence of having once supported simple life, and projects such as SETI have attempted to detect radio transmissions from possible alien civilizations. According to the panspermia hypothesis, microscopic life exists throughout the Universe, and is distributed by meteoroids, asteroids and planetoids.[13] The meaning of life—its significance, origin, purpose, and ultimate fate—is a central concept and question in philosophy and religion. Both philosophy and religion have offered interpretations as to how life relates to existence and consciousness, and on related issues such as life stance, purpose, conception of a god or gods, a soul or an afterlife. Different cultures throughout history have had widely varying approaches to these issues. Contents [hide] 1 Early theories 1.1 Materialism 1.2 Hylomorphism 1.3 Vitalism 2 Definitions 2.1 Biology 2.2 Living systems theories 3 Origin 4 Conditions 4.1 Range of tolerance 5 Form and function 6 Classification 7 Extraterrestrial life 7.1 Research 8 Death 9 Artificial life 10 See also 11 Notes 12 References 13 Further reading 14 External links Early theories

Materialism

Plant growth in the Hoh Rainforest

Herds of zebra and impala gathering on the Maasai Mara plain

An aerial photo of microbial mats around the Grand Prismatic Spring of Yellowstone National Park Some of the earliest theories of life were materialist, holding that all that exists is matter, and that life is merely a complex form or arrangement of matter. Empedocles (430 BC) argued that every thing in the universe is made up of a combination of four eternal "elements" or "roots of all": earth, water, air, and fire. All change is explained by the arrangement and rearrangement of these four elements. The various forms of life are caused by an appropriate mixture of elements.[14] Democritus (460 BC) thought that the essential characteristic of life is having a soul (psyche). Like other ancient writers, he was attempting to explain what makes something a living thing. His explanation was that fiery atoms make a soul in exactly the same way atoms and void account for any other thing. He elaborates on fire because of the apparent connection between life and heat, and because fire moves.[15] Plato's world of eternal and unchanging Forms, imperfectly represented in matter by a divine Artisan, contrasts sharply with the various mechanistic Weltanschauungen, of which atomism was, by the fourth century at least, the most prominent... This debate persisted throughout the ancient world. Atomistic mechanism got a shot in the arm from Epicurus... while the Stoics adopted a divine teleology... The choice seems simple: either show how a structured, regular world could arise out of undirected processes, or inject intelligence into the system.[16] —R. J. Hankinson, Cause and Explanation in Ancient Greek Thought The mechanistic materialism that originated in ancient Greece was revived and revised by the French philosopher René Descartes, who held that animals and humans were assemblages of parts that together functioned as a machine. In the 19th century, the advances in cell theory in biological science encouraged this view. The evolutionary theory of Charles Darwin (1859) is a mechanistic explanation for the origin of species by means of natural selection.[17] Hylomorphism Hylomorphism is a theory (originating with Aristotle (322 BC)) that all things are a combination of matter and form. Biology was one of his main interests, and there is extensive biological material in his extant writings. In this view, all things in the material universe have both matter and form, and the form of a living thing is its soul (Greek psyche, Latin anima). There are three kinds of souls: the vegetative soul of plants, which causes them to grow and decay and nourish themselves, but does not cause motion and sensation; the animal soul, which causes animals to move and feel; and the rational soul, which is the source of consciousness and reasoning, which (Aristotle believed) is found only in man.[18] Each higher soul has all the attributes of the lower one. Aristotle believed that while matter can exist without form, form cannot exist without matter, and therefore the soul cannot exist without the body.[19] This account is consistent with teleological explanations of life, which account for phenomena in terms of purpose or goal-directedness. Thus, the whiteness of the polar bear's coat is explained by its purpose of camouflage. The direction of causality (from the future to the past) is in contradiction with the scientific evidence for natural selection, which explains the consequence in terms of a prior cause. Biological features are explained not by looking at future optimal results, but by looking at the past evolutionary history of a species, which led to the natural selection of the features in question.[20] Vitalism Vitalism is the belief that the life-principle is non-material. This originated with Stahl (17th century), and held sway until the middle of the 19th century. It appealed to philosophers such as Henri Bergson, Nietzsche, Wilhelm Dilthey,[21] anatomists like Bichat, and chemists like Liebig.[22] Vitalism included the idea that there was a fundamental difference between organic and inorganic material, and the belief that organic material can only be derived from living things. This was disproved in 1828, when Friedrich Wöhler prepared urea from inorganic materials.[23] This Wöhler synthesis is considered the starting point of modern organic chemistry. It is of historical significance because for the first time an organic compound was produced from inorganic reactants.[22] During the 1850s, Helmholtz, anticipated by Mayer, demonstrated that no energy is lost in muscle movement, suggesting that there were no "vital forces" necessary to move a muscle.[24] These results led to the abandonment of scientific interest in vitalistic theories, although the belief lingered on in pseudoscientific theories such as homeopathy, which interprets diseases and sickness as caused by disturbances in a hypothetical vital force or life force.[25] Definitions

It is a challenge for scientists and philosophers to define life in unequivocal terms.[26][27][28] This is difficult partly because life is a process, not a pure substance.[29][30] Any definition must be sufficiently broad to encompass all life with which we are familiar, and must be sufficiently general to include life that may be fundamentally different from life on Earth.[31][32][33] Biology Since there is no unequivocal definition of life, the current understanding is descriptive. Life is considered a characteristic of organisms that exhibit all or most of the following characteristics or traits:[32][34][35] Homeostasis: Regulation of the internal environment to maintain a constant state; for example, electrolyte concentration or sweating to reduce temperature. Organization: Being structurally composed of one or more cells — the basic units of life. Metabolism: Transformation of energy by converting chemicals and energy into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life. Growth: Maintenance of a higher rate of anabolism than catabolism. A growing organism increases in size in all of its parts, rather than simply accumulating matter. Adaptation: The ability to change over time in response to the environment. This ability is fundamental to the process of evolution and is determined by the organism's heredity, diet, and external factors. Response to stimuli: A response can take many forms, from the contraction of a unicellular organism to external chemicals, to complex reactions involving all the senses of multicellular organisms. A response is often expressed by motion; for example, the leaves of a plant turning toward the sun (phototropism), and chemotaxis. Reproduction: The ability to produce new individual organisms, either asexually from a single parent organism, or sexually from two parent organisms. These complex processes, called physiological functions, have underlying physical and chemical bases, as well as signaling and control mechanisms that are essential to maintaining life. Alternatives See also: Entropy and life To reflect the minimum phenomena required, other biological definitions of life have been proposed,[36] many of these are based upon chemical systems. Biophysicists have commented that living things function on negative entropy.[37][38] In other words, living processes can be viewed as a delay of the spontaneous diffusion or dispersion of the internal energy of biological molecules towards more potential microstates.[39] In more detail, according to physicists such as John Bernal, Erwin Schrödinger, Eugene Wigner, and John Avery, life is a member of the class of phenomena that are open or continuous systems able to decrease their internal entropy at the expense of substances or free energy taken in from the environment and subsequently rejected in a degraded form.[40][41][42] At a higher level, living beings are thermodynamic systems that have an organized molecular structure.[39] That is, life is matter that can reproduce itself and evolve as survival dictates.[43][44] Hence, life is a self-sustained chemical system capable of undergoing Darwinian evolution.[45] Others take a systemic viewpoint that does not necessarily depend on molecular chemistry. One systemic definition of life is that living things are self-organizing and autopoietic (self-producing). Variations of this definition include Stuart Kauffman's definition as an autonomous agent or a multi-agent system capable of reproducing itself or themselves, and of completing at least one thermodynamic work cycle.[46] Life can be modeled as a network of inferior negative feedbacks of regulatory mechanisms subordinated to a superior positive feedback formed by the potential of expansion and reproduction.[47] Alternatively, life can be said to consist of things with the capacity for metabolism and motion,[32] or that life is self-reproduction "with variations"[48][49] or "with an error rate below the sustainability threshold."[49] Viruses

Electron micrograph of adenovirus with a cartoon to demonstrate its icosahedral structure Viruses are most often considered replicators rather than forms of life. They have been described as "organisms at the edge of life,"[50] since they possess genes, evolve by natural selection,[51][52] and replicate by creating multiple copies of themselves through self-assembly. However, viruses do not metabolize and they require a host cell to make new products. Virus self-assembly within host cells has implications for the study of the origin of life, as it may support the hypothesis that life could have started as self-assembling organic molecules.[53][54][55] Living systems theories The idea that the Earth is alive is found in philosophy and religion, but the first scientific discussion of it was by the Scottish scientist James Hutton. In 1785, he stated that the Earth was a superorganism and that its proper study should be physiology. Hutton is considered the father of geology, but his idea of a living Earth was forgotten in the intense reductionism of the 19th century.[56] The Gaia hypothesis, proposed in the 1960s by scientist James Lovelock,[57][58] suggests that life on Earth functions as a single organism that defines and maintains environmental conditions necessary for its survival.[59] The first attempt at a general living systems theory for explaining the nature of life was in 1978, by American biologist James Grier Miller.[60] Such a general theory, arising out of the ecological and biological sciences, attempts to map general principles for how all living systems work. Instead of examining phenomena by attempting to break things down into component parts, a general living systems theory explores phenomena in terms of dynamic patterns of the relationships of organisms with their environment.[61] Robert Rosen (1991) built on this by defining a system component as "a unit of organization; a part with a function, i.e., a definite relation between part and whole." From this and other starting concepts, he developed a "relational theory of systems" that attempts to explain the special properties of life. Specifically, he identified the "nonfractionability of components in an organism" as the fundamental difference between living systems and "biological machines."[62] A systems view of life treats environmental fluxes and biological fluxes together as a "reciprocity of influence",[63] and a reciprocal relation with environment is arguably as important for understanding life as it is for understanding ecosystems. As Harold J. Morowitz (1992) explains it, life is a property of an ecological system rather than a single organism or species.[64] He argues that an ecosystemic definition of life is preferable to a strictly biochemical or physical one. Robert Ulanowicz (2009) highlights mutualism as the key to understand the systemic, order-generating behavior of life and ecosystems.[65] Complex systems biology (CSB) is a field of science that studies the emergence of complexity in functional organisms from the viewpoint of dynamic systems theory.[66] The latter is often called also systems biology and aims to understand the most fundamental aspects of life. A closely related approach to CSB and systems biology, called relational biology,[67][68] is concerned mainly with understanding life processes in terms of the most important relations, and categories of such relations among the essential functional components of organisms; for multicellular organisms, this has been defined as "categorical biology", or a model representation of organisms as a category theory of biological relations, and also an algebraic topology of the functional organization of living organisms in terms of their dynamic, complex networks of metabolic, genetic, epigenetic processes and signaling pathways.[citation needed] It has also been argued that the evolution of order in living systems and certain physical systems obey a common fundamental principle termed the Darwinian dynamic.[69][70] The Darwinian dynamic was formulated by first considering how macroscopic order is generated in a simple non-biological system far from thermodynamic equilibrium, and then extending consideration to short, replicating RNA molecules. The underlying order generating process for both types of system was concluded to be basically similar.[71] Origin

Main article: Abiogenesis Evidence suggests that life on Earth has existed for about 3.7 billion years,[72] with the oldest traces of life found in fossils dating back 3.4 billion years.[73] In a National Institutes of Health study, the authors hypothesize that if biological complexity increased exponentially during evolution, life in the universe may have begun nearly 10 billion years ago[74][75] - billions of years before the Earth existed, suggesting that Earth was seeded by panspermia or directed panspermia. All known life forms share fundamental molecular mechanisms, reflecting their common descent; based on these observations, hypotheses on the origin of life attempt to find a mechanism explaining the formation of a universal common ancestor, from simple organic molecules via pre-cellular life to protocells and metabolism. Models have been divided into "genes-first" and "metabolism-first" categories, but a recent trend is the emergence of hybrid models that combine both categories.[76] There is no current scientific consensus as to how life originated. However, most accepted scientific models build on the following observations: The Miller-Urey experiment, and the work of Sidney Fox, show that conditions on the primitive Earth favored chemical reactions that synthesize amino acids and other organic compounds from inorganic precursors.[77] Phospholipids spontaneously form lipid bilayers, the basic structure of a cell membrane. Living organisms synthesize proteins, which are polymers of amino acids using instructions encoded by deoxyribonucleic acid (DNA). Protein synthesis entails intermediary ribonucleic acid (RNA) polymers. One possibility for how life began is that genes originated first, followed by proteins;[78] the alternative being that proteins came first and then genes.[79] However, since genes and proteins are both required to produce the other, the problem of considering which came first is like that of the chicken or the egg. Most scientists have adopted the hypothesis that because of this, it is unlikely that genes and proteins arose independently.[80] Therefore, a possibility, first suggested by Francis Crick,[81] is that the first life was based on RNA,[80] which has the DNA-like properties of information storage and the catalytic properties of some proteins. This is called the RNA world hypothesis, and it is supported by the observation that many of the most critical components of cells (those that evolve the slowest) are composed mostly or entirely of RNA. Also, many critical cofactors (ATP, Acetyl-CoA, NADH, etc.) are either nucleotides or substances clearly related to them. The catalytic properties of RNA had not yet been demonstrated when the hypothesis was first proposed,[82] but they were confirmed by Thomas Cech in 1986.[83] One issue with the RNA world hypothesis is that synthesis of RNA from simple inorganic precursors is more difficult than for other organic molecules. One reason for this is that RNA precursors are very stable and react with each other very slowly under ambient conditions, and it has also been proposed that living organisms consisted of other molecules before RNA.[84] However, the successful synthesis of certain RNA molecules under the conditions that existed prior to life on Earth has been achieved by adding alternative precursors in a specified order with the precursor phosphate present throughout the reaction.[85] This study makes the RNA world hypothesis more plausible.[86] Geological findings in 2013 showed that reactive phosphorus species (like phosphite) were in abundance in the ocean before 3.5 Ga, and that Schreibersite easily reacts with aqueous glycerol to generate phosphite and glycerol 3-phosphate.[87] It is hypothesized that Schreibersite-containing meteorites from the Late Heavy Bombardment could have provided early reduced phosphorus, which could react with prebiotic organic molecules to form phosphorylated biomolecules, like RNA. In 2009, experiments demonstrated Darwinian evolution of a two-component system of RNA enzymes (ribozymes) in vitro.[88] The work was performed in the laboratory of Gerald Joyce, who stated, "This is the first example, outside of biology, of evolutionary adaptation in a molecular genetic system."[89] Prebiotic compounds may have extraterrestrial origin. NASA findings in 2011, based on studies with meteorites found on Earth, suggest DNA and RNA components (adenine, guanine and related organic molecules) may be formed in outer space.[90][91][92][93] Conditions

Cyanobacteria dramatically changed the composition of life forms on Earth by leading to the near-extinction of oxygen-intolerant organisms. The diversity of life on Earth is a result of the dynamic interplay between genetic opportunity, metabolic capability, environmental challenges,[94] and symbiosis.[95][96][97] For most of its existence, Earth's habitable environment has been dominated by microorganisms and subjected to their metabolism and evolution. As a consequence of these microbial activities, the physical-chemical environment on Earth has been changing on a geologic time scale, thereby affecting the path of evolution of subsequent life.[94] For example, the release of molecular oxygen by cyanobacteria as a by-product of photosynthesis induced global changes in the Earth's environment. Since oxygen was toxic to most life on Earth at the time, this posed novel evolutionary challenges, and ultimately resulted in the formation of our planet's major animal and plant species. This interplay between organisms and their environment is an inherent feature of living systems.[94] All life forms require certain core chemical elements needed for biochemical functioning. These include carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur—the elemental macronutrients for all organisms[98]—often represented by the acronym CHNOPS. Together these make up nucleic acids, proteins and lipids, the bulk of living matter. Five of these six elements comprise the chemical components of DNA, the exception being sulfur. The latter is a component of the amino acids cysteine and methionine. The most biologically abundant of these elements is carbon, which has the desirable attribute of forming multiple, stable covalent bonds. This allows carbon-based (organic) molecules to form an immense variety of chemical arrangements.[99] Alternative hypothetical types of biochemistry have been proposed that eliminate one or more of these elements, swap out an element for one not on the list, or change required chiralities or other chemical properties.[100][101] Range of tolerance The inert components of an ecosystem are the physical and chemical factors necessary for life — energy (sunlight or chemical energy), water, temperature, atmosphere, gravity, nutrients, and ultraviolet solar radiation protection.[102] In most ecosystems, the conditions vary during the day and from one season to the next. To live in most ecosystems, then, organisms must be able to survive a range of conditions, called the "range of tolerance."[103] Outside that are the "zones of physiological stress," where the survival and reproduction are possible but not optimal. Beyond these zones are the "zones of intolerance," where survival and reproduction of that organism is unlikely or impossible. Organisms that have a wide range of tolerance are more widely distributed than organisms with a narrow range of tolerance.[103]

Deinococcus radiodurans is an extremophile that can resist extremes of cold, dehydration, vacuum, acid, and radiation exposure. To survive, selected microorganisms can assume forms that enable them to withstand freezing, complete desiccation, starvation, high levels of radiation exposure, and other physical or chemical challenges. These microorganisms may survive exposure to such conditions for weeks, months, years, or even centuries.[94] Extremophiles are microbial life forms that thrive outside the ranges where life is commonly found. They excel at exploiting uncommon sources of energy. While all organisms are composed of nearly identical molecules, evolution has enabled such microbes to cope with this wide range of physical and chemical conditions. Characterization of the structure and metabolic diversity of microbial communities in such extreme environments is ongoing.[104] On 17 March 2013, researchers reported data that suggested microbial life forms thrive in the Mariana Trench, the deepest spot on the Earth.[105][106] Other researchers reported related studies that microbes thrive inside rocks up to 1900 feet below the sea floor under 8500 feet of ocean off the coast of the northwestern United States.[105][107] According to one of the researchers,"You can find microbes everywhere — they're extremely adaptable to conditions, and survive wherever they are."[105] Investigation of the tenacity and versatility of life on Earth, as well as an understanding of the molecular systems that some organisms utilize to survive such extremes, is important for the search for life beyond Earth.[94] In April 2012, scientists reported that lichen could survive for a month in a simulated Martian environment.[108][109] Form and function

Cells are the basic unit of structure in every living thing, and all cells arise from pre-existing cells by division. Cell theory was formulated by Henri Dutrochet, Theodor Schwann, Rudolf Virchow and others during the early nineteenth century, and subsequently became widely accepted.[110] The activity of an organism depends on the total activity of its cells, with energy flow occurring within and between them. Cells contain hereditary information that is carried forward as a genetic code during cell division.[111] There are two primary types of cells. Prokaryotes lack a nucleus and other membrane-bound organelles, although they have circular DNA and ribosomes. Bacteria and Archaea are two domains of prokaryotes. The other primary type of cells are the eukaryotes, which have distinct nuclei bound by a nuclear membrane and membrane-bound organelles, including mitochondria, chloroplasts, lysosomes, rough and smooth endoplasmic reticulum, and vacuoles. In addition, they possess organized chromosomes that store genetic material. All species of large complex organisms are eukaryotes, including animals, plants and fungi, though most species of eukaryote are protist microorganisms.[112] The conventional model is that eukaryotes evolved from prokaryotes, with the main organelles of the eukaryotes forming through endosymbiosis between bacteria and the progenitor eukaryotic cell.[113] The molecular mechanisms of cell biology are based on proteins. Most of these are synthesized by the ribosomes through an enzyme-catalyzed process called protein biosynthesis. A sequence of amino acids is assembled and joined together based upon gene expression of the cell's nucleic acid.[114] In eukaryotic cells, these proteins may then be transported and processed through the Golgi apparatus in preparation for dispatch to their destination. Cells reproduce through a process of cell division in which the parent cell divides into two or more daughter cells. For prokaryotes, cell division occurs through a process of fission in which the DNA is replicated, then the two copies are attached to parts of the cell membrane. In eukaryotes, a more complex process of mitosis is followed. However, the end result is the same; the resulting cell copies are identical to each other and to the original cell (except for mutations), and both are capable of further division following an interphase period.[115] Multicellular organisms may have first evolved through the formation of colonies of like cells. These cells can form group organisms through cell adhesion. The individual members of a colony are capable of surviving on their own, whereas the members of a true multi-cellular organism have developed specialties, making them dependent on the remainder of the organism for survival. Such organisms are formed clonally or from a single germ cell that is capable of forming the various specialized cells that form the adult organism. This specialization allows multicellular organisms to exploit resources more efficiently than single cells.[116] Cells have evolved methods to perceive and respond to their microenvironment, thereby enhancing their adaptability. Cell signaling coordinates cellular activities, and hence governs the basic functions of multicellular organisms. Signaling between cells can occur through direct cell contact using juxtacrine signalling, or indirectly through the exchange of agents as in the endocrine system. In more complex organisms, coordination of activities can occur through a dedicated nervous system.[117] Classification

Main article: Biological classification

The hierarchy of biological classification's eight major taxonomic ranks. Life is divided into domains, which are subdivided into further groups. Intermediate minor rankings are not shown. The first known attempt to classify organisms was conducted by the Greek philosopher Aristotle (384–322 BC), who classified all living organisms known at that time as either a plant or an animal, based mainly on their ability to move. He also distinguished animals with blood from animals without blood (or at least without red blood), which can be compared with the concepts of vertebrates and invertebrates respectively, and divided the blooded animals into five groups: viviparous quadrupeds (mammals), oviparous quadrupeds (reptiles and amphibians), birds, fishes and whales. The bloodless animals were also divided into five groups: cephalopods, crustaceans, insects (which included the spiders, scorpions, and centipedes, in addition to what we define as insects today), shelled animals (such as most molluscs and echinoderms) and "zoophytes." Though Aristotle's work in zoology was not without errors, it was the grandest biological synthesis of the time and remained the ultimate authority for many centuries after his death.[118] The exploration of the American continent revealed large numbers of new plants and animals that needed descriptions and classification. In the latter part of the 16th century and the beginning of the 17th, careful study of animals commenced and was gradually extended until it formed a sufficient body of knowledge to serve as an anatomical basis for classification. In the late 1740s, Carolus Linnaeus introduced his system of binomial nomenclature for the classification of species.[119] Linnaeus attempted to improve the composition and reduce the length of the previously used many-worded names by abolishing unnecessary rhetoric, introducing new descriptive terms and precisely defining their meaning. By consistently using this system, Linnaeus separated nomenclature from taxonomy. The fungi were originally treated as plants. For a short period Linnaeus had classified them in the taxon Vermes in Animalia, but later placed them back in Plantae. Copeland classified the Fungi in his Protoctista, thus partially avoiding the problem but acknowledging their special status.[120] The problem was eventually solved by Whittaker, when he gave them their own kingdom in his five-kingdom system. Evolutionary history shows that the fungi are more closely related to animals than to plants.[121] As new discoveries enabled detailed study of cells and microorganisms, new groups of life were revealed, and the fields of cell biology and microbiology were created. These new organisms were originally described separately in protozoa as animals and protophyta/thallophyta as plants, but were united by Haeckel in the kingdom Protista; later, the prokaryotes were split off in the kingdom Monera, which would eventually be divided into two separate groups, the Bacteria and the Archaea. This led to the six-kingdom system and eventually to the current three-domain system, which is based on evolutionary relationships.[122] However, the classification of eukaryotes, especially of protists, is still controversial.[123] As microbiology, molecular biology and virology developed, non-cellular reproducing agents were discovered, such as viruses and viroids. Whether these are considered alive has been a matter of debate; viruses lack characteristics of life such as cell membranes, metabolism and the ability to grow or respond to their environments. Viruses can still be classed into "species" based on their biology and genetics, but many aspects of such a classification remain controversial.[124] In the 1960s a trend called cladistics emerged, arranging taxa based on clades in an evolutionary or phylogenetic tree.[125] Linnaeus 1735[126] Haeckel 1866[127] Chatton 1925[128] Copeland 1938[120] Whittaker 1969[129] Woese et al. 1990[122] Cavalier-Smith 1998[130] 2 kingdoms 3 kingdoms 2 empires 4 kingdoms 5 kingdoms 3 domains 6 kingdoms (not treated) Protista Prokaryota Monera Monera Bacteria Bacteria Archaea Eukaryota Protoctista Protista Eucarya Protozoa Chromista Vegetabilia Plantae Plantae Plantae Plantae Fungi Fungi Animalia Animalia Animalia Animalia Animalia Main article: Kingdom (biology)#Summary Extraterrestrial life

Main articles: Extraterrestrial life, Astrobiology, Astroecology , and Life in the solar system

Panspermia hypothesis showing bacteria being carried to Earth by a comet Earth is the only planet known to harbor life. Other locations within the Solar System that may host life include subsurface Mars, the atmosphere of Venus,[131] and subsurface oceans on some of the moons of the gas giant planets.[132] The Drake equation, which predicts the number of extraterrestrial civilizations in our galaxy with which we might come in contact, has been used to discuss the probability of life elsewhere, but many of the variables in this equation are difficult to estimate.[133] The region around a main sequence star that could support Earth-like life on an Earth-like planet is known as the habitable zone. The inner and outer radii of this zone vary with the luminosity of the star, as does the time interval during which the zone survives. Stars more massive than the Sun have a larger habitable zone, but remain on the main sequence for a shorter time interval. Small red dwarf stars have the opposite problem, with a smaller habitable zone that is subject to higher levels of magnetic activity and the effects of tidal locking from close orbits. Hence, stars in the intermediate mass range such as the Sun may have a greater likelihood for Earth-like life to develop.[134] The location of the star within a galaxy may also have an impact on the likelihood of life forming. Stars in regions with a greater abundance of heavier elements that can form planets, in combination with a low rate of potentially habitat-damaging supernova events, are predicted to have a higher probability of hosting planets with complex life.[135] Panspermia, also called exogenesis, is the hypothesis that life originated elsewhere in the universe and subsequently transferred to Earth in the form of spores via meteorites, comets, or cosmic dust. Conversely, terrestrial life may be seeded in other solar systems through directed panspermia, to secure and expand some terrestrial life forms.[29][30][33] Astroecology experiments with meteorites show that Martian asteroids and cometary materials are rich in inorganic elements and may be fertile soils for microbial, algal and plant life, for past and future life in our and other solar systems.[136] Research See also: List of molecules in interstellar space In 2004, scientists reported[137] detecting the spectral signatures of anthracene and pyrene in the ultraviolet light emitted by the Red Rectangle nebula (no other such complex molecules had ever been found before in outer space). This discovery was considered a confirmation of a hypothesis that as nebulae of the same type as the Red Rectangle approach the ends of their lives, convection currents cause carbon and hydrogen in the nebulae's core to get caught in stellar winds, and radiate outward.[138] As they cool, the atoms supposedly bond to each other in various ways and eventually form particles of a million or more atoms. The scientists inferred[137] that since they discovered polycyclic aromatic hydrocarbons (PAHs) — which may have been vital in the formation of early life on Earth — in a nebula, by necessity they must originate in nebulae.[138] In August 2009, NASA scientists identified one of the fundamental chemical building-blocks of life (the amino acid glycine) in a comet for the first time.[139] In 2010, fullerenes (or "buckyballs") were detected in nebulae.[140] Fullerenes have been implicated in the origin of life; according to astronomer Letizia Stanghellini, "It's possible that buckyballs from outer space provided seeds for life on Earth."[141] In August 2011, findings by NASA, based on studies of meteorites found on Earth, suggests DNA and RNA components (adenine, guanine and related organic molecules), building blocks for life as we know it, may be formed extraterrestrially in outer space.[90][91][92] In October 2011, scientists found using spectroscopy that cosmic dust contains complex organic matter ("amorphous organic solids with a mixed aromatic-aliphatic structure") that could be created naturally, and rapidly, by stars.[142][143][144] The compounds are so complex that their chemical structures resemble the makeup of coal and petroleum; such chemical complexity was previously thought to arise only from living organisms.[142] These observations suggest that organic compounds introduced on Earth by interstellar dust particles could serve as basic ingredients for life due to their surface-catalytic activities.[93][145] One of the scientists suggested that these compounds may have been related to the development of life on Earth and said that, "If this is the case, life on Earth may have had an easier time getting started as these organics can serve as basic ingredients for life."[142] In August 2012, astronomers at Copenhagen University reported the detection of a specific sugar molecule, glycolaldehyde, in a distant star system. The molecule was found around the protostellar binary IRAS 16293-2422, which is located 400 light years from Earth.[146][147] Glycolaldehyde is needed to form ribonucleic acid, or RNA, which is similar in function to DNA. This finding suggests that complex organic molecules may form in stellar systems prior to the formation of planets, eventually arriving on young planets early in their formation.[148] In September 2012, NASA scientists reported that polycyclic aromatic hydrocarbons (PAHs), subjected to interstellar medium (ISM) conditions, are transformed, through hydrogenation, oxygenation and hydroxylation, to more complex organics - "a step along the path toward amino acids and nucleotides, the raw materials of proteins and DNA, respectively".[149][150] Further, as a result of these transformations, the PAHs lose their spectroscopic signature which could be one of the reasons "for the lack of PAH detection in interstellar ice grains, particularly the outer regions of cold, dense clouds or the upper molecular layers of protoplanetary disks."[149][150] In June 2013, polycyclic aromatic hydrocarbons (PAHs) were detected in the upper atmosphere of Titan, the largest moon of the planet Saturn.[151] In 2013, the Atacama Large Millimeter Array (ALMA Project) confirmed that researchers have discovered an important pair of prebiotic molecules in the icy particles in interstellar space (ISM). The chemicals, found in a giant cloud of gas about 25,000 light-years from Earth in ISM, may be a precursor to a key component of DNA and the other may have a role in the formation of an important amino acid. Researchers found a molecule called cyanomethanimine, which produces adenine, one of the four nucleobases that form the “rungs” in the ladder-like structure of DNA. The other molecule, called ethanamine, is thought to play a role in forming alanine, one of the twenty amino acids in the genetic code. Previously, scientists thought such processes took place in the very tenuous gas between the stars. The new discoveries, however, suggest that the chemical formation sequences for these molecules occurred not in gas, but on the surfaces of ice grains in interstellar space.[152] NASA ALMA scientist Anthony Remijan stated that finding these molecules in an interstellar gas cloud means that important building blocks for DNA and amino acids can 'seed' newly formed planets with the chemical precursors for life.[153] In January 2014, NASA reported that current studies on the planet Mars by the Curiosity and Opportunity rovers will now be searching for evidence of ancient life, including a biosphere based on autotrophic, chemotrophic and/or chemolithoautotrophic microorganisms, as well as ancient water, including fluvio-lacustrine environments (plains related to ancient rivers or lakes) that may have been habitable.[154][155][156][157] The search for evidence of habitability, taphonomy (related to fossils), and organic carbon on the planet Mars is now a primary NASA objective.[154] Death

Main article: Death

Animal corpses, like this African buffalo, are recycled by the ecosystem, providing energy and nutrients for living creatures Death is the permanent termination of all vital functions or life processes in an organism or cell.[158][159] It can occur as a result of an accident, medical conditions, biological interaction, malnutrition, poisoning, senescence, or suicide. After death, the remains of an organism re-enter the biogeochemical cycle. Organisms may be consumed by a predator or a scavenger and leftover organic material may then be further decomposed by detritivores, organisms that recycle detritus, returning it to the environment for reuse in the food chain. One of the challenges in defining death is in distinguishing it from life. Death would seem to refer to either the moment life ends, or when the state that follows life begins.[159] However, determining when death has occurred requires drawing precise conceptual boundaries between life and death. This is problematic, however, because there is little consensus over how to define life. The nature of death has for millennia been a central concern of the world's religious traditions and of philosophical inquiry. Many religions maintain faith in either a kind of afterlife or reincarnation for the soul, or resurrection of the body at a later date. Extinction is the process by which a group of taxa or species dies out, reducing biodiversity.[160] The moment of extinction is generally considered the death of the last individual of that species. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively after a period of apparent absence. Species become extinct when they are no longer able to survive in changing habitat or against superior competition. In Earth's history, over 99% of all the species that have ever lived have gone extinct;[161] however, mass extinctions may have accelerated evolution by providing opportunities for new groups of organisms to diversify.[162] Fossils are the preserved remains or traces of animals, plants, and other organisms from the remote past. The totality of fossils, both discovered and undiscovered, and their placement in fossil-containing rock formations and sedimentary layers (strata) is known as the fossil record. A preserved specimen is called a fossil if it is older than the arbitrary date of 10,000 years ago.[163] Hence, fossils range in age from the youngest at the start of the Holocene Epoch to the oldest from the Archaean Eon, up to 3.4 billion years old.[164][165] Artificial life

Main articles: Artificial life and Synthetic biology Artificial life is a field of study that examines systems related to life, its processes, and its evolution through simulations using computer models, robotics, and biochemistry.[166] The study of artificial life imitates traditional biology by recreating some aspects of biological phenomena. Scientists study the logic of living systems by creating artificial environments—seeking to understand the complex information processing that defines such systems. While life is, by definition, alive, artificial life is generally referred to as data confined to a digital environment and existence. Synthetic biology is a new area of biological research and technology that combines science and biological engineering. The common goal is the design and construction of new biological functions and systems not found in nature. Synthetic biology includes the broad redefinition and expansion of biotechnology, with the ultimate goals of being able to design and build engineered biological systems that process information, manipulate chemicals, fabricate materials and structures, produce energy, provide food, and maintain and enhance human health and our environment.[167] See also

Alpha taxonomy Astroecology Biological organisation Biosignature Chronobiology Conway's Game of Life Constructal law Evolutionary history of life Life on Mars Life skills Lists of organisms by population Meaning of life Non-cellular life Personal life Phylogenetics Quality of life Notes

Jump up ^ The 'evolution' of viruses and other similar forms is still uncertain. Therefore, this classification may be paraphyletic because cellular life might have evolved from non-cellular life, or polyphyletic because the most recent common ancestor might not be included. References

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PMID 19131595. Jump up ^ Joyce, Gerald F. (2009). "Evolution in an RNA world". Cold Spring Harbor Symposium on Quantitative Biology 74: 17–23. doi:10.1101/The Yeti or Abominable Snowman (Nepali: हिममानव, lit. "mountain man") is an ape-like cryptid taller than an average human that is said to inhabit the Himalayan region of Nepal and Tibet.[3] The names Yeti and Meh-Teh are commonly used by the people indigenous to the region, and are part of their history and mythology. Stories of the Yeti first emerged as a facet of Western popular culture in the 19th century. The scientific community generally regards the Yeti as a legend, given the lack of conclusive evidence,[4] but it remains one of the most famous creatures of cryptozoology. Analysis of samples associated with claimed yetis found a sequence of mitochondrial DNA that matched a sample from an ancient polar bear jawbone found in Norway, that dates back to between 40,000 and 120,000 years ago. Contents [hide] 1 Etymology and alternate names 1.1 The "Abominable Snowman" 2 History 2.1 Pre-19th century 2.2 19th century 2.3 20th century 2.4 21st century 3 Possible explanations 4 In popular culture 4.1 Films 4.2 Television 4.3 Video games 4.4 Literature 4.5 Music 4.6 Attractions 5 See also 6 References 7 Bibliography 8 Further reading Etymology and alternate names

This article contains Tibetan script. Without proper rendering support, you may see question marks, boxes, or other symbols instead of Tibetan characters. The word Yeti is derived from Tibetan: གཡའ་དྲེད་, Wylie: g.ya' dred, ZYPY: Yachê), a compound of the words Tibetan: གཡའ་, Wylie: g.ya', ZYPY: ya "rocky", "rocky place" and (Tibetan: དྲེད་, Wylie: dred, ZYPY: chê) "bear".[5][6][7][8][9] Pranavananda[5] states that the words "ti", "te" and "teh" are derived from the spoken word 'tre' (spelled "dred"), Tibetan for bear, with the 'r' so softly pronounced as to be almost inaudible, thus making it "te" or "teh".[5][9][10][11] Other terms used by Himalayan peoples do not translate exactly the same, but refer to legendary and indigenous wildlife: Michê (Tibetan: མི་དྲེད་, Wylie: mi dred, ZYPY: Michê) translates as "man-bear".[7][9][12] Dzu-teh – 'dzu' translates as "cattle" and the full meaning translates as "cattle bear", referring to the Himalayan brown bear.[6][9][10][13][14] Migoi or Mi-go (Tibetan: མི་རྒོད་, Wylie: mi rgod, ZYPY: Migö/Mirgö) translates as "wild man".[10][14] Bun Manchi - Nepali for "jungle man" that is used outside Sherpa communities where yeti is the common name.[15] Mirka – another name for "wild-man". Local legend holds that "anyone who sees one dies or is killed". The latter is taken from a written statement by Frank Smythe's sherpas in 1937.[16] Kang Admi – "Snow Man".[14] The "Abominable Snowman" The appellation "Abominable Snowman" was coined in 1921, the same year Lieutenant-Colonel Charles Howard-Bury led the joint Alpine Club and Royal Geographical Society "Everest Reconnaissance Expedition"[17][18] which he chronicled in Mount Everest The Reconnaissance, 1921.[19] In the book, Howard-Bury includes an account of crossing the "Lhakpa-la" at 21,000 ft (6,400 m) where he found footprints that he believed "were probably caused by a large 'loping' grey wolf, which in the soft snow formed double tracks rather like a those of a bare-footed man". He adds that his Sherpa guides "at once volunteered that the tracks must be that of 'The Wild Man of the Snows', to which they gave the name 'metoh-kangmi'".[19] "Metoh" translates as "man-bear" and "Kang-mi" translates as "snowman".[5][7][14][20] Confusion exists between Howard-Bury's recitation of the term "metoh-kangmi"[17][19] and the term used in Bill Tilman's book Mount Everest, 1938[21] where Tilman had used the words "metch", which does not exist in the Tibetan language,[22] and "kangmi" when relating the coining of the term "Abominable Snowman".[7][14][21][23] Further evidence of "metch" being a misnomer is provided by Tibetan language authority Professor David Snellgrove from the School of Oriental and African Studies at the University of London (ca. 1956), who dismissed the word "metch" as impossible, because the consonants "t-c-h" cannot be conjoined in the Tibetan language."[22] Documentation suggests that the term "metch-kangmi" is derived from one source (from the year 1921).[21] It has been suggested that "metch" is simply a misspelling of "metoh". The use of "Abominable Snowman" began when Henry Newman, a longtime contributor to The Statesman in Calcutta, writing under the pen name "Kim",[8] interviewed the porters of the "Everest Reconnaissance expedition" on their return to Darjeeling.[21][24][25][26] Newman mistranslated the word "metoh" as "filthy", substituting the term "abominable", perhaps out of artistic license.[27] As author Bill Tilman recounts, "[Newman] wrote long after in a letter to The Times: The whole story seemed such a joyous creation I sent it to one or two newspapers'".[21] History

Pre-19th century According to H. Siiger, the Yeti was a part of the pre-Buddhist beliefs of several Himalayan people. He was told that the Lepcha people worshipped a "Glacier Being" as a God of the Hunt. He also reported that followers of the Bön religion once believed the blood of the "mi rgod" or "wild man" had use in certain mystical ceremonies. The being was depicted as an apelike creature who carries a large stone as a weapon and makes a whistling swoosh sound.[28] 19th century In 1832, James Prinsep's Journal of the Asiatic Society of Bengal published trekker B. H. Hodgson's account of his experiences in northern Nepal. His local guides spotted a tall, bipedal creature covered with long dark hair, which seemed to flee in fear. Hodgson concluded it was an orangutan. An early record of reported footprints appeared in 1899 in Laurence Waddell's Among the Himalayas.[29] Waddell reported his guide's description of a large apelike creature that left the prints, which Waddell thought were made by a bear. Waddell heard stories of bipedal, apelike creatures but wrote that "none, however, of the many Tibetans I have interrogated on this subject could ever give me an authentic case. On the most superficial investigation it always resolved into something that somebody heard tell of."[30] 20th century The frequency of reports increased during the early 20th century, when Westerners began making determined attempts to scale the many mountains in the area and occasionally reported seeing odd creatures or strange tracks. In 1925, N. A. Tombazi, a photographer and member of the Royal Geographical Society, writes that he saw a creature at about 15,000 ft (4,600 m) near Zemu Glacier. Tombazi later wrote that he observed the creature from about 200 to 300 yd (180 to 270 m), for about a minute. "Unquestionably, the figure in outline was exactly like a human being, walking upright and stopping occasionally to pull at some dwarf rhododendron bushes. It showed up dark against the snow, and as far as I could make out, wore no clothes." About two hours later, Tombazi and his companions descended the mountain and saw the creature's prints, described as "similar in shape to those of a man, but only six to seven inches long by four inches wide[31]... The prints were undoubtedly those of a biped."[32] Western interest in the Yeti peaked dramatically in the 1950s. While attempting to scale Mount Everest in 1951, Eric Shipton took photographs of a number of large prints in the snow, at about 6,000 m (20,000 ft) above sea level. These photos have been subject to intense scrutiny and debate. Some argue they are the best evidence of Yeti's existence, while others contend the prints are those of a mundane creature that have been distorted by the melting snow.[33] Peter Byrne reported finding a yeti footprint in 1948, in northern Sikkim, India near the Zemu Glacier, while on holiday from a Royal Air Force assignment in India.[34] In 1953, Sir Edmund Hillary and Tenzing Norgay reported seeing large footprints while scaling Mount Everest. Hillary would later discount Yeti reports as unreliable. In his first autobiography Tenzing said that he believed the Yeti was a large ape, and although he had never seen it himself his father had seen one twice, but in his second autobiography he said he had become much more skeptical about its existence.[35] During the Daily Mail Snowman Expedition of 1954,[36] the mountaineering leader John Angelo Jackson made the first trek from Everest to Kanchenjunga in the course of which he photographed symbolic paintings of the Yeti at Tengboche gompa.[37] Jackson tracked and photographed many footprints in the snow, most of which were identifiable. However, there were many large footprints which could not be identified. These flattened footprint-like indentations were attributed to erosion and subsequent widening of the original footprint by wind and particles.

Dr. Biswamoy Biswas examining the Pangboche Yeti scalp during the Daily Mail Snowman Expedition of 1954 On 19 March 1954, the Daily Mail printed an article which described expedition teams obtaining hair specimens from what was alleged to be a Yeti scalp found in the Pangboche monastery. The hairs were black to dark brown in colour in dim light, and fox red in sunlight. The hair was analysed by Professor Frederic Wood Jones,[38][39] an expert in human and comparative anatomy. During the study, the hairs were bleached, cut into sections and analysed microscopically. The research consisted of taking microphotographs of the hairs and comparing them with hairs from known animals such as bears and orangutans. Jones concluded that the hairs were not actually from a scalp. He contended that while some animals do have a ridge of hair extending from the pate to the back, no animals have a ridge (as in the Pangboche "scalp") running from the base of the forehead across the pate and ending at the nape of the neck. Jones was unable to pinpoint exactly the animal from which the Pangboche hairs were taken. He was, however, convinced that the hairs were not of a bear or anthropoid ape. He suggested that the hairs were from the shoulder of a coarse-haired hoofed animal.[40] Sławomir Rawicz claimed in his book The Long Walk, published in 1956, that as he and some others were crossing the Himalayas in the winter of 1940, their path was blocked for hours by two bipedal animals that were doing seemingly nothing but shuffling around in the snow. Beginning in 1957, a very wealthy American oilman Tom Slick funded a few missions to investigate Yeti reports. In 1959, supposed Yeti feces were collected by one of Slick's expeditions; fecal analysis found a parasite which could not be classified. Cryptozoologist Bernard Heuvelmans wrote, "Since each animal has its own parasites, this indicated that the host animal is equally an unknown animal."[41][42] The United States government thought that finding the Yeti was likely enough to create three rules for American expeditions searching for it: obtain a Nepalese permit, do not harm the Yeti except in self-defense, and let the Nepalese government approve any news reporting on the animal's discovery.[43] In 1959, actor James Stewart, while visiting India, reportedly smuggled remains of a supposed Yeti, the so-called Pangboche Hand, by concealing it in his luggage when he flew from India to London.[44] In 1960, Hillary mounted an expedition to collect and analyze physical evidence of the Yeti. He sent a supposed Yeti "scalp" from the Khumjung monastery to the West for testing, whose results indicated the scalp was manufactured from the skin of a serow, a goat-like Himalayan antelope. Up to the 1960s, belief in the yeti was relatively common in Bhutan and in 1966 a Bhutanese stamp was made to honor the creature.[45] However, in the twenty-first century belief in the being has declined.[46] In 1970, British mountaineer Don Whillans claimed to have witnessed a creature when scaling Annapurna.[47] According to Whillans, while scouting for a campsite, he heard some odd cries which his Sherpa guide attributed to a Yeti's call. That night, he saw a dark shape moving near his camp. The next day, he observed a few human-like footprints in the snow, and that evening, viewed with binoculars a bipedal, ape-like creature for 20 minutes as it apparently searched for food not far from his camp.[citation needed] In 1983, Himalayan conservationist Daniel C. Taylor and Himalayan natural historian Robert L. Fleming Jr. led a yeti expedition into Nepal’s Barun Valley (suggested by discovery in the Barun in 1972 of footprints alleged to be yeti by Cronin & McNeely [48]). The Taylor-Fleming expedition also discovered similar yeti-like footprints (hominoid appearing with both a hallux and bipedal gait), intriguing large nests in trees, and vivid reports from local villagers of two bears, rukh balu ('tree bear', small, reclusive, weighing about 150 pounds) and bhui balu ('ground bear,' aggressive, weighing up to 400 pounds). Further interviews across Nepal gave evidence of local belief in two different bears. Skulls were collected, these were compared to known skulls at the Smithsonian Institution, American Museum of Natural History, and British Museum, and confirmed identification of a single species, the Asiatic Black Bear, showing no morphological difference between 'tree bear' and 'ground bear.' [49] (This despite an intriguing skull in the British Museum of a 'tree bear' collected in 1869 by Oldham and discussed in the Annals of the Royal Zoological Society .). There is a famous Yeti hoax, known as the Snow Walker Film. The footage was created for Paramount's UPN show, Paranormal Borderland, ostensibly by the show's producers. The show ran from 12 March to 6 August 1996. Fox purchased and used the footage in their later program on The World's Greatest Hoaxes.[50] 21st century In 2004, Henry Gee, editor of the journal Nature, mentioned the Yeti as an example of a legend deserving further study, writing, "The discovery that Homo floresiensis survived until so very recently, in geological terms, makes it more likely that stories of other mythical, human-like creatures such as Yetis are founded on grains of truth ... Now, cryptozoology, the study of such fabulous creatures, can come in from the cold."[51] The Yeti is said to have been spotted in the remote Mae Charim area of the Luang Prabang Range range, between the Thai Highlands and Sainyabuli Province, Laos.[52] In early December 2007, American television presenter Joshua Gates and his team (Destination Truth) reported finding a series of footprints in the Everest region of Nepal resembling descriptions of Yeti.[53] Each of the footprints measured 33 cm (13 in) in length with five toes that measured a total of 25 cm (9.8 in) across. Casts were made of the prints for further research. The footprints were examined by Jeffrey Meldrum of Idaho State University, who believed them to be too morphologically accurate to be fake or man-made, before changing his mind after making further investigations.[54] Later in 2009, Gates made another investigation during which he discovered hair samples. A forensic analyst concluded that the hair contained an unknown DNA sequence.[55] On 25 July 2008, the BBC reported that hairs collected in the remote Garo Hills area of North-East India by Dipu Marak had been analyzed at Oxford Brookes University in the UK by primatologist Anna Nekaris and microscopy expert Jon Wells. These initial tests were inconclusive, and ape conservation expert Ian Redmond told the BBC that there was similarity between the cuticle pattern of these hairs and specimens collected by Edmund Hillary during Himalayan expeditions in the 1950s and donated to the Oxford University Museum of Natural History, and announced planned DNA analysis.[56] This analysis has since revealed that the hair came from the Himalayan Goral.[57] On 20 October 2008 a team of seven Japanese adventurers photographed footprints which could allegedly have been made by a Yeti. The team's leader, Yoshiteru Takahashi claims to have observed a Yeti on a 2003 expedition and is determined to capture the creature on film. A group of Chinese scientists and explorers in 2010 proposed to renew searches in Shennongjia province, which was the site of expeditions in the 1970s and 1980s.[58] At a 2011 conference in Russia, participating scientists and enthusiasts declared having "95% evidence" of the Yeti's existence.[59] However, this claim was disputed later; American anthropologist and anatomist Jeffrey Meldrum, who was present during the Russian expedition, claimed the "evidence" found was simply an attempt by local officials to drum up publicity.[60] A yeti was reportedly captured in Russia in December 2011.[61] A hunter reported having seen a bear like creature, trying to kill one of his sheep, but after he fired his gun, the creature ran into a forest on 2 legs. Border patrol soldiers then captured a hairy 2-legged female creature that ate meat and vegetation. The creature allegedly was more similar to a gorilla than a bear, but its arms were shorter than the legs (in contrast to a gorilla). It was about 2 meters (6 feet 7 inches) tall. This was later revealed as a hoax, or possibly a publicity stunt for charity.[62] Possible explanations

Misidentification of Himalayan wildlife has been proposed as an explanation for some Yeti sightings, including the Chu-Teh, a Langur monkey[63] living at lower altitudes, the Tibetan blue bear, the Himalayan brown bear or Dzu-Teh, also known as the Himalayan red bear.[63] Some have also suggested the Yeti could actually be a human hermit. A well publicised expedition to Bhutan reported that a hair sample had been obtained which by DNA analysis by Professor Bryan Sykes could not be matched to any known animal.[64] Analysis completed after the media release, however, clearly showed the samples were from a Brown bear (Ursus arctos) and an Asiatic black bear (Ursus thibetanus).[65] In 1986, South Tyrolean mountaineer Reinhold Messner claimed to have a face-to-face encounter with a Yeti. He wrote a book, My Quest for the Yeti, and claims to have killed one. According to Messner, the Yeti is actually the endangered Himalayan brown bear, Ursus arctos isabellinus, which can walk both upright or on all fours.[66] The 1983 Barun Valley discoveries prompted three years of research on the 'tree bear' possibility by Taylor, Fleming, John Craighead and Tirtha Shrestha. From that research the conclusion was that the Asiatic Black Bear, when about two years old, spends much time in trees to avoid attack by larger male bears on the ground ('ground bears'). During this tree period that may last two years, young bears train their inner claw outward, allowing an opposable grip. The imprint in the snow of a hind paw coming over the front paw that appears to have a hallux, especially when the bear is going slightly uphill so the hind paw print extends the overprint backward makes a hominoid-appearing track, both in that it is elongated like a human foot but with a “thumb” and in that a four-footed animal’s gait now appears bipedal.[67] This “yeti discovery”, in the words of National Geographic Magazine editor Bill Garrett, “[by] on-site research sweeps away much of the ‘smoke and mirrors’ and gives us a believable yeti”.[68] This fieldwork in Nepal’s Barun Valley led directly to initiating in 1984 Makalu-Barun National Park that protected over half a million acres in 1991, and across the border with China the Qomolangma national nature preserve in the Tibet Autonomous Region that protected over six million acres. In the words of Honorary President of the American Alpine Club, Robert H. Bates, this yeti discovery "has apparently solved the mystery of the yeti, or at least part of it, and in so doing added to the world’s great wildlife preserves"[69] such that the shy animal that lives in trees (and not the high snows), and mysteries and myths of the Himalayas that it represents, can continue within a protected area nearly the size of Switzerland. In 2003, Japanese researcher and mountaineer Dr. Makoto Nebuka published the results of his twelve-year linguistic study, postulating that the word "Yeti" is a corruption of the word "meti", a regional dialect term for a "bear". Nebuka claims that ethnic Tibetans fear and worship the bear as a supernatural being.[70] Nebuka's claims were subject to almost immediate criticism, and he was accused of linguistic carelessness. Dr. Raj Kumar Pandey, who has researched both Yetis and mountain languages, said "it is not enough to blame tales of the mysterious beast of the Himalayas on words that rhyme but mean different things."[71] Some speculate these reported creatures could be present-day specimens of the extinct giant ape Gigantopithecus.[72][73][74][75] However, the Yeti is generally described as bipedal, and most scientists believe Gigantopithecus to have been quadrupedal, and so massive that, unless it evolved specifically as a bipedal ape (like Oreopithecus and the hominids), walking upright would have been even more difficult for the now extinct primate than it is for its extant quadrupedal relative, the orangutan. In 2013 a call was put out by scientists from the universities of Oxford and Lausanne for people claiming to have samples from these sorts of creatures. A mitochondrial DNA analysis of the 12S RNA gene was undertaken on samples of hair from an unidentified animal from Ladakh in northern India on the west of the Himalayas, and one from Bhutan. These samples were compared with those in GenBank, the international repository of gene sequences, and matched a sample from an ancient polar bear jawbone found in Svalbard, Norway, that dates back to between 40,000 and 120,000 years ago.[76] The result suggests that, barring hoaxes of planted samples or contamination, bears in these regions may have been taken to be yeti.[77] Professor of evolutionary genetics at the University of Cambridge Bill Amos doubted the samples were of polar bears in the Himalayas, but was "90% convinced that there is a bear in these regions that has been mistaken for a yeti". Professor Brian Sykes whose team carried out the analysis of the samples at Oxford university has his own theory. He believes that the samples may have come from a hybrid species of bear produced from a mating between a brown bear and a polar bear. Sykes told the BBC: “ I think this bear, which nobody has seen alive, may still be there and may have quite a lot of polar bear in it. It may be some sort of hybrid and if its behaviour is different from normal bears, which is what eyewitnesses report, then I think that may well be the source of the mystery and the source of the legend. ” —Dr. Bryan Sykes, BBC News (17 October 2013)[78][79] In popular culture

This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (November 2013) The Yeti has regularly been depicted in films, literature, music and video games.

An illustration of a Yeti. Artist Stanisław Szukalski's works all involve the Yeti; this involved painting, sculpture, and 2 books full of his artistic works: Inner Portraits (1980) and A Trough Full of Pearls / Behold! The Protong (1982). Szukalski also developed a philosophy known as Zermatism in which the Yeti play a central role, along with the Sons of Yeti ("Yetinsyny"), the half-breed offspring of Yetis and humans. Films Significant film appearances include The Snow Creature (1954), Half Human (1955), The Abominable Snowman (1957), One of Our Dinosaurs Is Missing (1975), Yeti – il gigante del 20. secolo (1977), Snowbeast (1977), Monsters, Inc. (2001), Yeti: A Love Story (2006), Chill Out, Scooby-Doo! (2007), The Mummy: Tomb of the Dragon Emperor (2008), Yeti: Curse of the Snow Demon, (2008) Yetiko Khojima (Yeti; in search of Yeti, 2010). Rage of the Yeti (2011), Hotel Transylvania (2012) and Monsters University (2013). Television The Yeti plays significant roles in some television shows including: The annual American Christmas broadcast special Rudolph the Red-Nosed Reindeer. Various Looney Tunes cartoons had Hugo the Abominable Snowman who is a Yeti. The Lost Tapes episode "Yeti" featured a Yeti. "The Abominable Snowmen" is a six-part serial from 1967 in the British science fiction television series Doctor Who that features the Yetis. In The Secret Saturdays, the character V.V. Argost is revealed to be a Yeti. A bunch of Yetis appeared in Ugly Americans. The Yetis appeared in the TV film Abominable Christmas. They are shown to have bear-like faces. Video games Several video games feature yeti-like creatures as opponents in icy or mountainous levels. The video game Urban Yeti! features a yeti as the main character who undergoes a quest to find a mate in a human city. In Ratchet & Clank: Going Commando, the frozen tundras of planet Grelbin are home to Yeti-like creatures (officially Y.E.T.I.) that attack Ratchet in his search for Moonstones. In Spyro: Year of the Dragon, one of the playable characters is a club-wielding yet eloquently-spoken yeti named Bentley. In Dangerous Hunts 2, the last enemy faced is a Yeti. The final mystery enemy from Carnivores: Ice Age is a yeti. In the Pokémon series, the Pokémon Abomasnow is loosely based on a Yeti. Literature In literature the Yeti has appeared prominently in many works, including Tintin in Tibet by Hergé, in Martin Mystère by Alfredo Castelli, in The Abominable Snowman of Pasadena by R. L. Stine and a gamebook in the Choose Your Own Adventure series. The Abominable Snowman is a superhero character in the Marvel Comics publications and the Snowman is a similar character in DC Comics. Music American heavy metal band High On Fire included their song "The Yeti" on their second album Surrounded by Thieves. Rock band Clutch have a track entitled "The Yeti" on their third album The Elephant Riders. A psychedelic trance collaboration called The Mystery of the Yeti, featuring many prominent names of the genre, was released on two albums between the years 1996 to 1999. Attractions Walt Disney World's attraction Expedition Everest at Disney's Animal Kingdom is themed around the folklore of the Yeti and features a 25-foot-tall audio-animatronic Yeti which appears during the ride.[80] At Disneyland, a similar ride named the Matterhorn Bobsleds features three audio-animatronic Abominable Snowmen. See also

General List of cryptids List of legendary creatures Tsul 'Kalu Denisova hominin Wild Man of the Navidad Similar alleged creatures Almas – Central Asia Amomongo – Philippines Ban-manush – Bangladesh Barmanou – Afghanistan and Pakistan Batutut – South-east Asia Bigfoot – North America Daeva or Div – Tajikistan, Iran Chuchunya – Siberia Fear liath – Scotland Fouke Monster – United States Genderuwa – Indonesia Grassman – United States Hibagon – Japan Mande Barung – India Mapinguari – South America Momo the Monster – United States Nuk-luk – Canada Orang Mawas – Malaysia Orang Pendek – Indonesia Sasquatch – North America Skunk ape – United States Yeren – China Yowie – Australia References

Jump up ^ Sullivan, Tim (10 August 2008). "Losing the yeti in the forgotten nation of Butan". The Victoria Advocate. Jump up ^ Bigfoot Files, Channel 4 (UK TV), November 2013 Jump up ^ Eberhart, George (2002). Mysterious Creatures: A Guide to Cryptozoology. ABC-CLIO. p. 613. ISBN 978-1-57607-283-7. Jump up ^ Napier, John (2005). Bigfoot: The Yeti and Sasquatch in Myth and Reality. London: N. Abbot. ISBN 0-525-06658-6. ^ Jump up to: a b c d Pranavananda, Swami (1957). "The Abominable Snowman". Journal of the Bombay Natural History Society 54. ^ Jump up to: a b Stonor, Charles (30 January 1954). The Statesman in Calcutta. ^ Jump up to: a b c d Swan, Lawrence W. (18 April 1958). "Abominable Snowman". Science 127 (3303): 882–884. doi:10.1126/science.127.3303.882-b. PMID 17733822. ^ Jump up to: a b Izzard, Ch. 2, pp. 21–22. ^ Jump up to: a b c d Heuvelmans, Bernard (1958). On the Track of Unknown Animals. Rupert Hart-Davis. p. 164. ^ Jump up to: a b c Izzard, Ch. 2, p. 199. Jump up ^ Stonor, Charles (1955 Daily Mail). The Sherpa and the Snowman. Hollis and Carter. "Abominable Snowman" redirects here. For other uses, see Abominable Snowman (disambiguation). For other uses of Yeti, see Yeti (disambiguation). Yeti (Abominable Snowman Migoi, Meh-teh et al.) Yetiscalp.JPG

Purported Yeti scalp at Khumjung monastery Grouping Cryptid Sub grouping Hominid Country Nepal, Bhutan,[1] China, India, Mongolia, Russia[2] Region Himalayas Habitat Mountains The Yeti or Abominable Snowman (Nepali: हिममानव, lit. "mountain man") is an ape-like cryptid taller than an average human that is said to inhabit the Himalayan region of Nepal and Tibet.[3] The names Yeti and Meh-Teh are commonly used by the people indigenous to the region, and are part of their history and mythology. Stories of the Yeti first emerged as a facet of Western popular culture in the 19th century. The scientific community generally regards the Yeti as a legend, given the lack of conclusive evidence,[4] but it remains one of the most famous creatures of cryptozoology. Analysis of samples associated with claimed yetis found a sequence of mitochondrial DNA that matched a sample from an ancient polar bear jawbone found in Norway, that dates back to between 40,000 and 120,000 years ago. Contents [hide] 1 Etymology and alternate names 1.1 The "Abominable Snowman" 2 History 2.1 Pre-19th century 2.2 19th century 2.3 20th century 2.4 21st century 3 Possible explanations 4 In popular culture 4.1 Films 4.2 Television 4.3 Video games 4.4 Literature 4.5 Music 4.6 Attractions 5 See also 6 References 7 Bibliography 8 Further reading Etymology and alternate names

This article contains Tibetan script. Without proper rendering support, you may see question marks, boxes, or other symbols instead of Tibetan characters. The word Yeti is derived from Tibetan: གཡའ་དྲེད་, Wylie: g.ya' dred, ZYPY: Yachê), a compound of the words Tibetan: གཡའ་, Wylie: g.ya', ZYPY: ya "rocky", "rocky place" and (Tibetan: དྲེད་, Wylie: dred, ZYPY: chê) "bear".[5][6][7][8][9] Pranavananda[5] states that the words "ti", "te" and "teh" are derived from the spoken word 'tre' (spelled "dred"), Tibetan for bear, with the 'r' so softly pronounced as to be almost inaudible, thus making it "te" or "teh".[5][9][10][11] Other terms used by Himalayan peoples do not translate exactly the same, but refer to legendary and indigenous wildlife: Michê (Tibetan: མི་དྲེད་, Wylie: mi dred, ZYPY: Michê) translates as "man-bear".[7][9][12] Dzu-teh – 'dzu' translates as "cattle" and the full meaning translates as "cattle bear", referring to the Himalayan brown bear.[6][9][10][13][14] Migoi or Mi-go (Tibetan: མི་རྒོད་, Wylie: mi rgod, ZYPY: Migö/Mirgö) translates as "wild man".[10][14] Bun Manchi - Nepali for "jungle man" that is used outside Sherpa communities where yeti is the common name.[15] Mirka – another name for "wild-man". Local legend holds that "anyone who sees one dies or is killed". The latter is taken from a written statement by Frank Smythe's sherpas in 1937.[16] Kang Admi – "Snow Man".[14] The "Abominable Snowman" The appellation "Abominable Snowman" was coined in 1921, the same year Lieutenant-Colonel Charles Howard-Bury led the joint Alpine Club and Royal Geographical Society "Everest Reconnaissance Expedition"[17][18] which he chronicled in Mount Everest The Reconnaissance, 1921.[19] In the book, Howard-Bury includes an account of crossing the "Lhakpa-la" at 21,000 ft (6,400 m) where he found footprints that he believed "were probably caused by a large 'loping' grey wolf, which in the soft snow formed double tracks rather like a those of a bare-footed man". He adds that his Sherpa guides "at once volunteered that the tracks must be that of 'The Wild Man of the Snows', to which they gave the name 'metoh-kangmi'".[19] "Metoh" translates as "man-bear" and "Kang-mi" translates as "snowman".[5][7][14][20] Confusion exists between Howard-Bury's recitation of the term "metoh-kangmi"[17][19] and the term used in Bill Tilman's book Mount Everest, 1938[21] where Tilman had used the words "metch", which does not exist in the Tibetan language,[22] and "kangmi" when relating the coining of the term "Abominable Snowman".[7][14][21][23] Further evidence of "metch" being a misnomer is provided by Tibetan language authority Professor David Snellgrove from the School of Oriental and African Studies at the University of London (ca. 1956), who dismissed the word "metch" as impossible, because the consonants "t-c-h" cannot be conjoined in the Tibetan language."[22] Documentation suggests that the term "metch-kangmi" is derived from one source (from the year 1921).[21] It has been suggested that "metch" is simply a misspelling of "metoh". The use of "Abominable Snowman" began when Henry Newman, a longtime contributor to The Statesman in Calcutta, writing under the pen name "Kim",[8] interviewed the porters of the "Everest Reconnaissance expedition" on their return to Darjeeling.[21][24][25][26] Newman mistranslated the word "metoh" as "filthy", substituting the term "abominable", perhaps out of artistic license.[27] As author Bill Tilman recounts, "[Newman] wrote long after in a letter to The Times: The whole story seemed such a joyous creation I sent it to one or two newspapers'".[21] History

Pre-19th century According to H. Siiger, the Yeti was a part of the pre-Buddhist beliefs of several Himalayan people. He was told that the Lepcha people worshipped a "Glacier Being" as a God of the Hunt. He also reported that followers of the Bön religion once believed the blood of the "mi rgod" or "wild man" had use in certain mystical ceremonies. The being was depicted as an apelike creature who carries a large stone as a weapon and makes a whistling swoosh sound.[28] 19th century In 1832, James Prinsep's Journal of the Asiatic Society of Bengal published trekker B. H. Hodgson's account of his experiences in northern Nepal. His local guides spotted a tall, bipedal creature covered with long dark hair, which seemed to flee in fear. Hodgson concluded it was an orangutan. An early record of reported footprints appeared in 1899 in Laurence Waddell's Among the Himalayas.[29] Waddell reported his guide's description of a large apelike creature that left the prints, which Waddell thought were made by a bear. Waddell heard stories of bipedal, apelike creatures but wrote that "none, however, of the many Tibetans I have interrogated on this subject could ever give me an authentic case. On the most superficial investigation it always resolved into something that somebody heard tell of."[30] 20th century The frequency of reports increased during the early 20th century, when Westerners began making determined attempts to scale the many mountains in the area and occasionally reported seeing odd creatures or strange tracks. In 1925, N. A. Tombazi, a photographer and member of the Royal Geographical Society, writes that he saw a creature at about 15,000 ft (4,600 m) near Zemu Glacier. Tombazi later wrote that he observed the creature from about 200 to 300 yd (180 to 270 m), for about a minute. "Unquestionably, the figure in outline was exactly like a human being, walking upright and stopping occasionally to pull at some dwarf rhododendron bushes. It showed up dark against the snow, and as far as I could make out, wore no clothes." About two hours later, Tombazi and his companions descended the mountain and saw the creature's prints, described as "similar in shape to those of a man, but only six to seven inches long by four inches wide[31]... The prints were undoubtedly those of a biped."[32] Western interest in the Yeti peaked dramatically in the 1950s. While attempting to scale Mount Everest in 1951, Eric Shipton took photographs of a number of large prints in the snow, at about 6,000 m (20,000 ft) above sea level. These photos have been subject to intense scrutiny and debate. Some argue they are the best evidence of Yeti's existence, while others contend the prints are those of a mundane creature that have been distorted by the melting snow.[33] Peter Byrne reported finding a yeti footprint in 1948, in northern Sikkim, India near the Zemu Glacier, while on holiday from a Royal Air Force assignment in India.[34] In 1953, Sir Edmund Hillary and Tenzing Norgay reported seeing large footprints while scaling Mount Everest. Hillary would later discount Yeti reports as unreliable. In his first autobiography Tenzing said that he believed the Yeti was a large ape, and although he had never seen it himself his father had seen one twice, but in his second autobiography he said he had become much more skeptical about its existence.[35] During the Daily Mail Snowman Expedition of 1954,[36] the mountaineering leader John Angelo Jackson made the first trek from Everest to Kanchenjunga in the course of which he photographed symbolic paintings of the Yeti at Tengboche gompa.[37] Jackson tracked and photographed many footprints in the snow, most of which were identifiable. However, there were many large footprints which could not be identified. These flattened footprint-like indentations were attributed to erosion and subsequent widening of the original footprint by wind and particles.

Dr. Biswamoy Biswas examining the Pangboche Yeti scalp during the Daily Mail Snowman Expedition of 1954 On 19 March 1954, the Daily Mail printed an article which described expedition teams obtaining hair specimens from what was alleged to be a Yeti scalp found in the Pangboche monastery. The hairs were black to dark brown in colour in dim light, and fox red in sunlight. The hair was analysed by Professor Frederic Wood Jones,[38][39] an expert in human and comparative anatomy. During the study, the hairs were bleached, cut into sections and analysed microscopically. The research consisted of taking microphotographs of the hairs and comparing them with hairs from known animals such as bears and orangutans. Jones concluded that the hairs were not actually from a scalp. He contended that while some animals do have a ridge of hair extending from the pate to the back, no animals have a ridge (as in the Pangboche "scalp") running from the base of the forehead across the pate and ending at the nape of the neck. Jones was unable to pinpoint exactly the animal from which the Pangboche hairs were taken. He was, however, convinced that the hairs were not of a bear or anthropoid ape. He suggested that the hairs were from the shoulder of a coarse-haired hoofed animal.[40] Sławomir Rawicz claimed in his book The Long Walk, published in 1956, that as he and some others were crossing the Himalayas in the winter of 1940, their path was blocked for hours by two bipedal animals that were doing seemingly nothing but shuffling around in the snow. Beginning in 1957, a very wealthy American oilman Tom Slick funded a few missions to investigate Yeti reports. In 1959, supposed Yeti feces were collected by one of Slick's expeditions; fecal analysis found a parasite which could not be classified. Cryptozoologist Bernard Heuvelmans wrote, "Since each animal has its own parasites, this indicated that the host animal is equally an unknown animal."[41][42] The United States government thought that finding the Yeti was likely enough to create three rules for American expeditions searching for it: obtain a Nepalese permit, do not harm the Yeti except in self-defense, and let the Nepalese government approve any news reporting on the animal's discovery.[43] In 1959, actor James Stewart, while visiting India, reportedly smuggled remains of a supposed Yeti, the so-called Pangboche Hand, by concealing it in his luggage when he flew from India to London.[44] In 1960, Hillary mounted an expedition to collect and analyze physical evidence of the Yeti. He sent a supposed Yeti "scalp" from the Khumjung monastery to the West for testing, whose results indicated the scalp was manufactured from the skin of a serow, a goat-like Himalayan antelope. Up to the 1960s, belief in the yeti was relatively common in Bhutan and in 1966 a Bhutanese stamp was made to honor the creature.[45] However, in the twenty-first century belief in the being has declined.[46] In 1970, British mountaineer Don Whillans claimed to have witnessed a creature when scaling Annapurna.[47] According to Whillans, while scouting for a campsite, he heard some odd cries which his Sherpa guide attributed to a Yeti's call. That night, he saw a dark shape moving near his camp. The next day, he observed a few human-like footprints in the snow, and that evening, viewed with binoculars a bipedal, ape-like creature for 20 minutes as it apparently searched for food not far from his camp.[citation needed] In 1983, Himalayan conservationist Daniel C. Taylor and Himalayan natural historian Robert L. Fleming Jr. led a yeti expedition into Nepal’s Barun Valley (suggested by discovery in the Barun in 1972 of footprints alleged to be yeti by Cronin & McNeely [48]). The Taylor-Fleming expedition also discovered similar yeti-like footprints (hominoid appearing with both a hallux and bipedal gait), intriguing large nests in trees, and vivid reports from local villagers of two bears, rukh balu ('tree bear', small, reclusive, weighing about 150 pounds) and bhui balu ('ground bear,' aggressive, weighing up to 400 pounds). Further interviews across Nepal gave evidence of local belief in two different bears. Skulls were collected, these were compared to known skulls at the Smithsonian Institution, American Museum of Natural History, and British Museum, and confirmed identification of a single species, the Asiatic Black Bear, showing no morphological difference between 'tree bear' and 'ground bear.' [49] (This despite an intriguing skull in the British Museum of a 'tree bear' collected in 1869 by Oldham and discussed in the Annals of the Royal Zoological Society .). There is a famous Yeti hoax, known as the Snow Walker Film. The footage was created for Paramount's UPN show, Paranormal Borderland, ostensibly by the show's producers. The show ran from 12 March to 6 August 1996. Fox purchased and used the footage in their later program on The World's Greatest Hoaxes.[50] 21st century In 2004, Henry Gee, editor of the journal Nature, mentioned the Yeti as an example of a legend deserving further study, writing, "The discovery that Homo floresiensis survived until so very recently, in geological terms, makes it more likely that stories of other mythical, human-like creatures such as Yetis are founded on grains of truth ... Now, cryptozoology, the study of such fabulous creatures, can come in from the cold."[51] The Yeti is said to have been spotted in the remote Mae Charim area of the Luang Prabang Range range, between the Thai Highlands and Sainyabuli Province, Laos.[52] In early December 2007, American television presenter Joshua Gates and his team (Destination Truth) reported finding a series of footprints in the Everest region of Nepal resembling descriptions of Yeti.[53] Each of the footprints measured 33 cm (13 in) in length with five toes that measured a total of 25 cm (9.8 in) across. Casts were made of the prints for further research. The footprints were examined by Jeffrey Meldrum of Idaho State University, who believed them to be too morphologically accurate to be fake or man-made, before changing his mind after making further investigations.[54] Later in 2009, Gates made another investigation during which he discovered hair samples. A forensic analyst concluded that the hair contained an unknown DNA sequence.[55] On 25 July 2008, the BBC reported that hairs collected in the remote Garo Hills area of North-East India by Dipu Marak had been analyzed at Oxford Brookes University in the UK by primatologist Anna Nekaris and microscopy expert Jon Wells. These initial tests were inconclusive, and ape conservation expert Ian Redmond told the BBC that there was similarity between the cuticle pattern of these hairs and specimens collected by Edmund Hillary during Himalayan expeditions in the 1950s and donated to the Oxford University Museum of Natural History, and announced planned DNA analysis.[56] This analysis has since revealed that the hair came from the Himalayan Goral.[57] On 20 October 2008 a team of seven Japanese adventurers photographed footprints which could allegedly have been made by a Yeti. The team's leader, Yoshiteru Takahashi claims to have observed a Yeti on a 2003 expedition and is determined to capture the creature on film. A group of Chinese scientists and explorers in 2010 proposed to renew searches in Shennongjia province, which was the site of expeditions in the 1970s and 1980s.[58] At a 2011 conference in Russia, participating scientists and enthusiasts declared having "95% evidence" of the Yeti's existence.[59] However, this claim was disputed later; American anthropologist and anatomist Jeffrey Meldrum, who was present during the Russian expedition, claimed the "evidence" found was simply an attempt by local officials to drum up publicity.[60] A yeti was reportedly captured in Russia in December 2011.[61] A hunter reported having seen a bear like creature, trying to kill one of his sheep, but after he fired his gun, the creature ran into a forest on 2 legs. Border patrol soldiers then captured a hairy 2-legged female creature that ate meat and vegetation. The creature allegedly was more similar to a gorilla than a bear, but its arms were shorter than the legs (in contrast to a gorilla). It was about 2 meters (6 feet 7 inches) tall. This was later revealed as a hoax, or possibly a publicity stunt for charity.[62] Possible explanations

Misidentification of Himalayan wildlife has been proposed as an explanation for some Yeti sightings, including the Chu-Teh, a Langur monkey[63] living at lower altitudes, the Tibetan blue bear, the Himalayan brown bear or Dzu-Teh, also known as the Himalayan red bear.[63] Some have also suggested the Yeti could actually be a human hermit. A well publicised expedition to Bhutan reported that a hair sample had been obtained which by DNA analysis by Professor Bryan Sykes could not be matched to any known animal.[64] Analysis completed after the media release, however, clearly showed the samples were from a Brown bear (Ursus arctos) and an Asiatic black bear (Ursus thibetanus).[65] In 1986, South Tyrolean mountaineer Reinhold Messner claimed to have a face-to-face encounter with a Yeti. He wrote a book, My Quest for the Yeti, and claims to have killed one. According to Messner, the Yeti is actually the endangered Himalayan brown bear, Ursus arctos isabellinus, which can walk both upright or on all fours.[66] The 1983 Barun Valley discoveries prompted three years of research on the 'tree bear' possibility by Taylor, Fleming, John Craighead and Tirtha Shrestha. From that research the conclusion was that the Asiatic Black Bear, when about two years old, spends much time in trees to avoid attack by larger male bears on the ground ('ground bears'). During this tree period that may last two years, young bears train their inner claw outward, allowing an opposable grip. The imprint in the snow of a hind paw coming over the front paw that appears to have a hallux, especially when the bear is going slightly uphill so the hind paw print extends the overprint backward makes a hominoid-appearing track, both in that it is elongated like a human foot but with a “thumb” and in that a four-footed animal’s gait now appears bipedal.[67] This “yeti discovery”, in the words of National Geographic Magazine editor Bill Garrett, “[by] on-site research sweeps away much of the ‘smoke and mirrors’ and gives us a believable yeti”.[68] This fieldwork in Nepal’s Barun Valley led directly to initiating in 1984 Makalu-Barun National Park that protected over half a million acres in 1991, and across the border with China the Qomolangma national nature preserve in the Tibet Autonomous Region that protected over six million acres. In the words of Honorary President of the American Alpine Club, Robert H. Bates, this yeti discovery "has apparently solved the mystery of the yeti, or at least part of it, and in so doing added to the world’s great wildlife preserves"[69] such that the shy animal that lives in trees (and not the high snows), and mysteries and myths of the Himalayas that it represents, can continue within a protected area nearly the size of Switzerland. In 2003, Japanese researcher and mountaineer Dr. Makoto Nebuka published the results of his twelve-year linguistic study, postulating that the word "Yeti" is a corruption of the word "meti", a regional dialect term for a "bear". Nebuka claims that ethnic Tibetans fear and worship the bear as a supernatural being.[70] Nebuka's claims were subject to almost immediate criticism, and he was accused of linguistic carelessness. Dr. Raj Kumar Pandey, who has researched both Yetis and mountain languages, said "it is not enough to blame tales of the mysterious beast of the Himalayas on words that rhyme but mean different things."[71] Some speculate these reported creatures could be present-day specimens of the extinct giant ape Gigantopithecus.[72][73][74][75] However, the Yeti is generally described as bipedal, and most scientists believe Gigantopithecus to have been quadrupedal, and so massive that, unless it evolved specifically as a bipedal ape (like Oreopithecus and the hominids), walking upright would have been even more difficult for the now extinct primate than it is for its extant quadrupedal relative, the orangutan. In 2013 a call was put out by scientists from the universities of Oxford and Lausanne for people claiming to have samples from these sorts of creatures. A mitochondrial DNA analysis of the 12S RNA gene was undertaken on samples of hair from an unidentified animal from Ladakh in northern India on the west of the Himalayas, and one from Bhutan. These samples were compared with those in GenBank, the international repository of gene sequences, and matched a sample from an ancient polar bear jawbone found in Svalbard, Norway, that dates back to between 40,000 and 120,000 years ago.[76] The result suggests that, barring hoaxes of planted samples or contamination, bears in these regions may have been taken to be yeti.[77] Professor of evolutionary genetics at the University of Cambridge Bill Amos doubted the samples were of polar bears in the Himalayas, but was "90% convinced that there is a bear in these regions that has been mistaken for a yeti". Professor Brian Sykes whose team carried out the analysis of the samples at Oxford university has his own theory. He believes that the samples may have come from a hybrid species of bear produced from a mating between a brown bear and a polar bear. Sykes told the BBC: “ I think this bear, which nobody has seen alive, may still be there and may have quite a lot of polar bear in it. It may be some sort of hybrid and if its behaviour is different from normal bears, which is what eyewitnesses report, then I think that may well be the source of the mystery and the source of the legend. ” —Dr. Bryan Sykes, BBC News (17 October 2013)[78][79] In popular culture

This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (November 2013) The Yeti has regularly been depicted in films, literature, music and video games.

An illustration of a Yeti. Artist Stanisław Szukalski's works all involve the Yeti; this involved painting, sculpture, and 2 books full of his artistic works: Inner Portraits (1980) and A Trough Full of Pearls / Behold! The Protong (1982). Szukalski also developed a philosophy known as Zermatism in which the Yeti play a central role, along with the Sons of Yeti ("Yetinsyny"), the half-breed offspring of Yetis and humans. Films Significant film appearances include The Snow Creature (1954), Half Human (1955), The Abominable Snowman (1957), One of Our Dinosaurs Is Missing (1975), Yeti – il gigante del 20. secolo (1977), Snowbeast (1977), Monsters, Inc. (2001), Yeti: A Love Story (2006), Chill Out, Scooby-Doo! (2007), The Mummy: Tomb of the Dragon Emperor (2008), Yeti: Curse of the Snow Demon, (2008) Yetiko Khojima (Yeti; in search of Yeti, 2010). Rage of the Yeti (2011), Hotel Transylvania (2012) and Monsters University (2013). Television The Yeti plays significant roles in some television shows including: The annual American Christmas broadcast special Rudolph the Red-Nosed Reindeer. Various Looney Tunes cartoons had Hugo the Abominable Snowman who is a Yeti. The Lost Tapes episode "Yeti" featured a Yeti. "The Abominable Snowmen" is a six-part serial from 1967 in the British science fiction television series Doctor Who that features the Yetis. In The Secret Saturdays, the character V.V. Argost is revealed to be a Yeti. A bunch of Yetis appeared in Ugly Americans. The Yetis appeared in the TV film Abominable Christmas. They are shown to have bear-like faces. Video games Several video games feature yeti-like creatures as opponents in icy or mountainous levels. The video game Urban Yeti! features a yeti as the main character who undergoes a quest to find a mate in a human city. In Ratchet & Clank: Going Commando, the frozen tundras of planet Grelbin are home to Yeti-like creatures (officially Y.E.T.I.) that attack Ratchet in his search for Moonstones. In Spyro: Year of the Dragon, one of the playable characters is a club-wielding yet eloquently-spoken yeti named Bentley. In Dangerous Hunts 2, the last enemy faced is a Yeti. The final mystery enemy from Carnivores: Ice Age is a yeti. In the Pokémon series, the Pokémon Abomasnow is loosely based on a Yeti. Literature In literature the Yeti has appeared prominently in many works, including Tintin in Tibet by Hergé, in Martin Mystère by Alfredo Castelli, in The Abominable Snowman of Pasadena by R. L. Stine and a gamebook in the Choose Your Own Adventure series. The Abominable Snowman is a superhero character in the Marvel Comics publications and the Snowman is a similar character in DC Comics. Music American heavy metal band High On Fire included their song "The Yeti" on their second album Surrounded by Thieves. Rock band Clutch have a track entitled "The Yeti" on their third album The Elephant Riders. A psychedelic trance collaboration called The Mystery of the Yeti, featuring many prominent names of the genre, was released on two albums between the years 1996 to 1999. Attractions Walt Disney World's attraction Expedition Everest at Disney's Animal Kingdom is themed around the folklore of the Yeti and features a 25-foot-tall audio-animatronic Yeti which appears during the ride.[80] At Disneyland, a similar ride named the Matterhorn Bobsleds features three audio-animatronic Abominable Snowmen. See also

General List of cryptids List of legendary creatures Tsul 'Kalu Denisova hominin Wild Man of the Navidad Similar alleged creatures Almas – Central Asia Amomongo – Philippines Ban-manush – Bangladesh Barmanou – Afghanistan and Pakistan Batutut – South-east Asia Bigfoot – North America Daeva or Div – Tajikistan, Iran Chuchunya – Siberia Fear liath – Scotland Fouke Monster – United States Genderuwa – Indonesia Grassman – United States Hibagon – Japan Mande Barung – India Mapinguari – South America Momo the Monster – United States Nuk-luk – Canada Orang Mawas – Malaysia Orang Pendek – Indonesia Sasquatch – North America Skunk ape – United States Yeren – China Yowie – Australia References

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"British scientist 'solves' mystery of Himalayan yetis". BBC News. Retrieved 22 October 2013. Jump up ^ Lawless, Jill (17 October 2013). "DNA Links Mysterious Yeti To Ancient Polar Bear". AP News. Retrieved 22 October 2013. Jump up ^ "Engineering Expedition Everest, complete with a yeti". Machine Design. 3 May 2009.Plants vs. Zombies is a 2009 tower defense video game developed and originally published by PopCap Games for Microsoft Windows and OS X. The game involves a homeowner using many varieties of plants to repel an army of zombies from "eating their brains". It was first released on May 5, 2009, and made available on Steam on the same day.[1][10] A version for iOS was released in February 2010, and an HD version for the iPad.[11] An extended Xbox Live Arcade version introducing new gameplay modes and features was released on September 8, 2010.[4] PopCap released a Nintendo DS version on January 18, 2011 with content unique to the platform.[12] The PlayStation 3 version was released in February 2011 also with added new co-op and versus modes found in the Xbox 360 version. An Android version of the game was released on May 31, 2011 on the Amazon App Store, while it was also released to the Android Market (now Google Play) on December 14, 2011.[13] On February 16, 2012, a version was released for BlackBerry PlayBook.[5] Later a BlackBerry smartphone version of the game was released on January 2013 following the launch of BlackBerry 10.[6] Furthermore, both the original Windows and Mac version of the game have been re-released with additional content in a Game of the Year version. The game received a positive response from critics, and was nominated for multiple Interactive Achievement Awards, alongside receiving praise for its musical score. A sequel, called Plants vs. Zombies 2: It's About Time, was released on August 15, 2013 for iOS. Contents [hide] 1 Gameplay 1.1 Game modes 2 Development 2.1 Concept 2.2 Design 2.3 Cultural references 3 Soundtrack 4 Reception 4.1 Awards 4.2 Legacy 5 Plants vs. Zombies Adventures 6 Sequels 7 See also 8 References 9 External links Gameplay[edit]

Gameplay in progress In Plants vs. Zombies, players place different types of plants and fungi, each with their own unique offensive or defensive capabilities, around a house in order to stop a horde of zombies from reaching the house of the residents. The playing field is divided into 5-6 horizontal lanes, and with rare exceptions, a zombie will only move towards the player's house along one lane (the main exception is if it has taken a bite out of a garlic). Planting costs "sun", which can be gathered for free (albeit slowly) during daytime levels and by planting certain plants or fungi. Most plants can only attack or defend against zombies in the lane they are planted in. In later levels, players can purchase upgrades with different offensive and defensive abilities. The game uses several different level types and layouts. The game starts out in a front yard, and progresses to nighttime levels, where the gameplay is more challenging, with no replenishing sun unless specific plants are used, the backyard is visited, with a pool added, and the final levels are nighttime pool levels (where fog fills the right half of the screen except when specific plants are used), a lightning storm level in pitch black (except when illuminated by occasional flashes of lightning), and rooftop levels (on the final level, the player must face a huge robot operated by a zombie known as Dr. Zomboss). Sporadically through the game, the player is either warned through a letter by zombies or addressed by Crazy Dave to prepare for an ambush, where the game takes on a bowling style, using Wall-nuts to bowl down zombies, or a modified version of regular levels, where random plant types come up on a small selection, and the player can use the plants without spending sun. The player starts with a limited number of seed pack types and seed pack slots that they can use during most levels. The number of slots can be increased through purchases with in-game money. At the start of a level, the player is shown the various types of zombies to expect and given the opportunity to select which seed packs to take into the level. Several plants are nocturnal, such as mushrooms, having a lower sunlight cost, and are ideal for nighttime levels. Certain plants are highly effective against specific types of zombies, such as the Magnet-shroom, which can remove metallic items from a zombie, such as helmets, buckets, ladders, and pogosticks. The zombies also come in a number of types that have different attributes, in particular, speed, damage tolerance, and abilities. Zombies include those wearing makeshift armour, those that are able to jump or fly over plants, and a dancing zombie which has different designs depending on the version that is able to summon other zombies from the ground. At various points the player will be inundated with a huge wave of zombies. Game modes[edit]Weightlifter Zombie is a zombie in Plants vs. Zombies Adventures. It seems that he lost his right arm, but has a very muscular left arm, and when he uses his barbell on a plant, the plant dies instantly. Weightlifter Zombie's weakness is the Magnet Plant, which takes the barbell.

Contents[hide] Facebook Description Appearances Strategies Gallery Trivia Facebook DescriptionEdit He lifts weights in order to make up for crippling anxiety over his merely average walking speed.

AppearancesEdit The Sever Glades: All levels The Sand Dooms: 7, 21 to 26 Zombitorium Manor: 8, 19 to 30 Reclaiming lots: The Chilly Lot, The Sunny Lot StrategiesEdit Use Shamrock, a Bamboo Shoot or a Repeater to kill it, Shamrock shoots far, so Shamrock won't get killed fast, Bamboo Shoot's projectile is very strong, but try to use Plant Perk on it to expand its range, and to prevent it from dying. Repeater is a good defense too, it has a very high damage.

For Brainball a good strategy for when one of these is spawned is to let it stay in the back until you get near a Wall-nut. Speed it up near it and let it eat the Wall-nut. If there are no more Wall-nuts, his dumbell makes a good defense.

GalleryEdit Weightlifter Animated Weightlifter Zombie Weight no arm Weightlifter Zombie without its arm Weightlifter Zombie in the game The Weightlifter Zombie in the game Please clean this =( Weightlifter Zombie trash item

Add a photo to this gallery TriviaEdit Weightlifter Zombie's handkerchief hat represents the American Flag. When the Weightlifter Zombie is in the Magnet Plant's range, the Magnet Plant attracts both the barbell and the Weightlifter Zombie's arm. This is possibly meaning that the Weightlifter Zombie's arm is not real, or it may be due to his grip on the barbell. When he loses his barbell, his speed remains the same, even though one would speed up after losing a heavy object. The Weightlifter Zombie is the only zombie that can lose both of his arms. When ever he loses his Barbell from damage, it plays the same animation of it eating a plant. You can hear a crunching noise be made when he drops it. There is a glitch that when it tries to eat a plant, it will drop the barbell, but when so many shots are hitting it, the animation will keep on looping, not defeating the plant. Zombies (Plants vs. Zombies Adventures) Zombies Zombie · Conehead Zombie · Barrel Zombie · Buckethead Zombie DJ Zom-B · Rocket Zombie · Conga Leader · Conga Dancer Football Zombie · Ice Block Zombie · Imposter Zombie · Imp Mall Cop Zombie · Weightlifter Zombie · Gas Can Zombie · Gargantuar Zombie Others Plants vs. Zombies Adventures Statues · Coach Zombie · Gallery of Zombies Start a Discussion Discussions about Weightlifter Zombie

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Categories: Gas Can Zombie is a zombie in Plants vs. Zombies Adventures. When this zombie is killed it explodes, which knocks out plants in a 3x3 radius. The Snow Pea, Ice Queen Pea and Chilly Pepper put out its cigar and gas can, which prevents him from exploding. It will also ignore any more plants along its track after being hit.

Contents[hide] Facebook Description Appearances Gallery Trivia Facebook DescriptionEdit He's here to help. Sure, his idea of help is insane, but that's what's airbrushed on the side of his van.

AppearancesEdit The Sand Dooms: All levels Zombitorium Manor: 1, 3, 4, 5, 11, 13 to 30 Reclaiming lots: The Sunny Lot GalleryEdit Gas Can no Gas Can A Gas Can Zombie without its gas can Gas 1st de Gas Can Zombie's first degrade GasCan2ndDegrade Gas Can Zombie's second degrade Gas Can explode The explosion made by Gas Can Zombie Gas Can Animated Gas Can Zombie

Add a photo to this gallery TriviaEdit Gas Can Zombie is similar to Jack-in-the-Box Zombie in Plants vs. Zombies. The only difference is that Gas Can Zombie explodes after it is killed, but Jack-in-the-Box Zombie can explode anytime. The Gas Can Zombie's explosion is the only zombie attack that can K.O. a Shamrock and Shamrockstar. It is possible the Gas Can Zombie gets his gas from all the gas stations in The Sand Dooms. Zombies (Plants vs. Zombies Adventures) Zombies Zombie · Conehead Zombie · Barrel Zombie · Buckethead Zombie DJ Zom-B · Rocket Zombie · Conga Leader · Conga Dancer Football Zombie · Ice Block Zombie · Imposter Zombie · Imp Mall Cop Zombie · Weightlifter Zombie · Gas Can Zombie · Gargantuar Zombie Others Plants vs. Zombies Adventures Statues · Coach Zombie · Gallery of Zombies Start a Discussion Discussions about Gas Can Zombie

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Categories: Zombies Plants vs. Zombies Adventures Plants vs. Zombies Adventures Zombies Headwear Zombies Add category Read moreMall Cop Zombie is a zombie in Plants vs. Zombies Adventures. It hops over the first path placed plants it runs into. It takes two Instant Kills to kill it.

Contents[hide] Appearances Strategies Gallery Trivia AppearancesEdit Mildew Meadow: 24 (possibly bug) Grey Matter Gardens: All levels The Sever Glades: 11, 14, 16, 17, 20, 22, 25 The Sand Dooms: 9, 15, 23, 24, 25, 26 Zombitorium Manor: 4, 6, 7, 9 to 15, 21 to 30 Reclaiming lots: The Fitness Lot StrategiesEdit One of the best options is to slow down Mall Cop Zombie, so that it will be easier to take down. Otherwise, using a Wall-nut to block him will suffice, as the segway gets instantly destroyed after vaulting over the Wall-nut. It will, however, continue to move inwards and eat plants that are behind the Wall-nut. It also takes two instant kills to kill him. Take caution when fighting the Mall Cop Zombies, as it is extremely dangerous, because it can easily overwhelm one's defenses when coming in large numbers.

In Brainball, the only way to get it in a wave is through it's own trained wave. This wave comes with Rocket Zombies (which are quite weak when you unlock them) and Imposter Zombies. A good method is to let the Rocket Zombies get ahead of the Mall Cop Zombies. These waves usually spawn with LOTS of Rocket Zombies, but usually only 1-2 Mall Cop Zombies. Once you run out of Rocket Zombies, (most likely) shamrocks will start attacking your Mall Cop Zombies. If it is near a Wall-nut, speed him up, he should jump it. If not, try to get the Imposter Zombies in front of it. Once it jumps over a Wall-nut, occasionally it may eat the Wall-nut behind it. If this happens, all other Mall Cop Zombies that jump will also. Save up your fog. If there are more Wall-nuts, repeat, if not, let the Mall Cop Zombie get ahead, speed it up. It will ignore all plants making an entrance to your target.

GalleryEdit Mall in-game In-game Mall Cop Zombie Mall no Seg Mall Cop Zombie without the segway MM lvl 24 Mall Cop Zombie in Mildew Meadow level 24 Mall Cop Zombie Animated Mall Cop Zombie Mall cop zombie without helmet A Mall Cop Zombie without Helmet

Add a photo to this gallery TriviaEdit It seems that Mall Cop Zombie is similar to Pole Vaulting Zombie in Plants vs. Zombies, except Mall Cop Zombie only jumps over Wall-nuts, it is probably because the other plants are on the side, not on the path. It is also much tougther then a Pole Vaulting Zombie. But the Popcorn, a plant that can be planted on paths, causes a bug where the Mall Cop Zombie will speed right through the Popcorn if it has not been fully "charged" to explode. There is a bug on Mildew Meadow Level 24 that the player will encounter Mall Cop Zombie even though it's encountered on Grey Matter Gardens Level 1, when Mall Cop Zombie hits a Wall-nut, the game will have an error, so try to kill Mall Cop Zombie without using any Wall-nuts. The Mall Cop Zombie is mistakenly called the Patrol Zombie inside the post to friends after the player discovers it. There is sometimes a bug on Mall Cop Zombie, where if the Segway is destroyed, the Mall Cop Zombie jumps and becomes invisible. If you look closely, you can see that one of the tires on his Segway is punctured. Zombies (Plants vs. Zombies Adventures) Zombies Zombie · Conehead Zombie · Barrel Zombie · Buckethead Zombie DJ Zom-B · Rocket Zombie · Conga Leader · Conga Dancer Football Zombie · Ice Block Zombie · Imposter Zombie · Imp Mall Cop Zombie · Weightlifter Zombie · Gas Can Zombie · Gargantuar Zombie Others Plants vs. Zombies Adventures Statues · Coach Zombie · Gallery of Zombies Start a Discussion Discussions about Mall Cop Zombie

I'm gonna hate this zombie for high health and speed 11 messages

BMCplayerDELREK wasnt it 3? 2 months ago

Milesprower2 No, 2. 2 months ago See more discussions > Categories: DJ Zom-B is a zombie in the game Plants vs. Zombies Adventures. It has nine degrades, five being a hat knocked off.

Contents[hide] Overview Facebook Description Strategies Appearances Gallery Trivia OverviewEdit The DJ Zom-B absorbs 32 normal damage shots and it degrades at 3, 6, 9, 12, 15 (at which point, all the hats are gone), 18, 21, 24 (at which point, the necklace is gone), 28, and finally dies at 32 normal damage shots.

Facebook DescriptionEdit “Gruhhhh braaaains,” moans DJ Zom-B. It’s a succinct and telling expression of his overall worldview.

-Plants vs. Zombies Adventures Facebook Page

StrategiesEdit When first discovered, it is quite hard to deal with, having a total of 32 hits. Plant some Beets next to a Wall-nut should do. If you are not using Beets, let it get in the range of most of your plants and then freeze it with Zombifreeze. This should take most of its hats off leaving little left. In farther levels, Flaming Peas should easily take off all the hats without any freezing. Once Bamboo Shoots are unlocked. DJ Zom-B becomes much weaker as one shot from a bamboo shoot will take of three hats at once. Magnet Plant can steal its necklace.

In Brainball, a wave of DJ Zom-B's come with lots of zombies. These should hoard around a Wall-nut and eat it quite fast. Just try to freeze Beets nearby. When spawned in Rocket Zombies, it's more the same thing as before. Just more zombies are spawned making it easier. When spawned in Conga Leader and Football Zombie waves, it is best to let them take hits and not the Conga Leaders. This will protect them, thus leading more spawned Conga Dancers.

AppearancesEdit Park-n-Perish: All levels except for 11, 21 Killjoy Park: All levels except for 9, 19 Sweaty Palms: All levels except for 1, 2, 6, 8, 18, 21 U of Z: 11, 12, 15, 17, 18, 19, 20, 22 Frostbite Falls: 3 to 7, 11, 12, 14, 18 to 23 Mildew Meadow: 1, 6, 7, 8, 9, 12 to 17, 20, 23, 24, 25, 26 Grey Matter Gardens: 1, 3, 4, 5, 8 to 12, 16, 17, 21, 22, 24 The Sever Glades: 2, 4 to 9, 11, 13, 16, 17, 20, 21, 22, 24, 26 The Sand Dooms: 1 to 6, 8, 10, 17 Zombitorium Manor: 1, 2, 3, 6 to 10, 16 to 20 Reclaiming lots: The Post Office Lot, The Cafe Lot, The Bamboo Lot, The Chilly Lot GalleryEdit DJZom-B DJ Zom-B's first official photo DJ Hat DJ Zom-B Hat trash DJZomBInGame DJ Zom-B in-game DJZomBAllHatsNoNecklace DJ Zom-B with all of its hats but no necklace DJ 1st First degrade DJ 2nd Second degrade DJ 3rd Third degrade DJ 4th Fourth degrade DJ 5 Fifth degrade DJ Animated DJ Zom-B

Add a photo to this gallery TriviaEdit It walks differently from other zombies. It half walks and half dances. This zombie was originally going to be called the Mad Hatter Zombie. If you look closely, you can see that the DJ Zom-B has a golden tooth. This zombie has the most degrades (nine) compared to any other zombie. Various artworks depict its necklace as a circle with a flipped Z in the middle, but in-game it is a golden skull. It is unknown how the Magnet Plant magnetizes the gold necklace since it is around his neck. Even assuming the Magnet Plant could get the necklace off the zombie, gold isn't magnetic, so the Magnet Plant shouldn't be able to steal it. In game, as DJ Zom-B's necklace degrades, it changes face. Zombies (Plants vs. Zombies Adventures) Zombies Zombie · Conehead Zombie · Barrel Zombie · Buckethead Zombie DJ Zom-B · Rocket Zombie · Conga Leader · Conga Dancer Football Zombie · Ice Block Zombie · Imposter Zombie · Imp Mall Cop Zombie · Weightlifter Zombie · Gas Can Zombie · Gargantuar Zombie Others Plants vs. Zombies Adventures Statues · Coach Zombie · Gallery of Zombies Start a Discussion Discussions about DJ Zom-B

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Categories: Zombies Plants vs. Zombies Adventures Zombies Zombies with "High" Toughness Plants vs. Zombies Adventures Headwear Zombies Add category Read more

Buckethead Zombie

Buckethead Zombie

Football Zombie

Football Zombie

Conehead Zombie

Conehead Zombie Showing 0 most recent 0 comments Nishanassaf

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See all photos See all photos > Live! The Lawn Plants vs. Zombies Wiki Go on the Lawn dsadas dasdas Around Wikdsadasia's networkRandom Wiki dsadasd [ VIDEO GAMES ] About Communitasdads The primary game mode is a single-player, multi-player and Adventure mode in which the player can earn money to spend at an in-game store to buy new seed packets and other bonuses. The game also features extra modes that are unlocked as the player progresses through the main adventure. These include a survival game with hard or normal mode, a puzzle mode which includes I, Zombie mode and Vasebreaker mode and a selection of mini-games which include zombie-themed versions of other PopCap games like Bejeweled. The game also features a Zen garden, where players can care for plants they acquire from successes in game play players can also buy other kinds of zen gardens in the in-game store. The in-game store also carries items that help with the Zen Garden. The PlayStation Network and Xbox Live Arcade version of the game includes 5 multiplayer modes, both co-operative and competitive, additional mini-games and a virtual house where players can show off their achievements to friends.[14][15] Development[edit]

[hide]System requirements Requirements Windows[1] Operating system Windows 7, Windows Vista, Windows XP CPU 1.2 GHz Memory 500 MB Hard drive space 65+ MB of free hard drive space Graphics hardware 128 MB of video memory, 16-bit or 32-bit color quality Sound hardware DirectX-compatible sound Mac[1] Operating system Mac OS X 10.4.11-10.6.x CPU 1.66 GHz+ (dual core) Memory 1 GB Hard drive space 50 MB Graphics hardware 64 MB of video memory, 16-bit or 32-bit color quality Sound hardware Standard audio Concept[edit] Plants vs. Zombies director George Fan intended on balancing the game between a "gritty" game and a "sickeningly cute" game. Strong strategic elements were included to appeal to more experienced gamers, while keeping it simple to appeal to casual gamers, without many tutorials. He was inspired to make it a tower defense game after both thinking of a more defense-oriented version of a previous title of his, Insaniquarium, and playing some Warcraft III tower defense mods.[16] While he was looking at the towers in Warcraft III, he felt that plants would make good towers. He wanted to bring something new to the genre with Plants vs. Zombies, and he found common tower defense game play elements such as mazing and juggling[17] to be too awkward, causing him to use the five and six lane set-ups that were used in the final version.[18][19] The game was initially going to be called Weedlings, but as the tower defense concept took off and the personality of the game as a whole evolved, the title was later changed.[20] Fan included elements from the trading card game Magic: The Gathering while teaching his girlfriend Laura Shigihara how to play it, showing her how to customize their decks. That inspired him to include the seed packets as opposed to using a conveyor belt that produced randomly selected plants, due to the complexity of this system. Another influence on Plants vs. Zombies besides Warcraft III and Insaniquarium was Tapper, crediting the use of five lanes to this game.[18][19] Various members of PopCap Games contributed to the development of Plants vs. Zombies through an internal forum where they gave feedback. Some of the characteristics that defined Insaniquarium influenced the development of Plants vs. Zombies. Players advance in a similar pace by receiving new plants. Also, the way plants are chosen at the beginning of each level was derived from the way pets are chosen in Insaniquarium.[18] Other inspiration for the game's mechanics came from the film Swiss Family Robinson, especially where the family defends against pirates. This was the inspiration for the Potato Mine; Fan stated that it was satisfying to watch a zombie step on the mine, being defeated and covered in mashed potatoes.[21] Design[edit] The team wanted to bring back the aliens from Insaniquarium, but in the end were changed to zombies, which players could react to more easily because of how slowly they moved. Fan's favorite zombie was the Pole Vaulting Zombie, due to the hilarity involved when a player encounters it for the first time, using a specific example where a player tries to block it with the Wall-Nut, only to have the zombie jump over it.[18][19][22] During development, it was discovered that newcomers to the genre of real-time strategy may have a hard time learning the concept behind sun collection. So, the price of the income generating sunflowers was dropped from 100 to 50 to encourage players to buy them over the attacking peashooter. As a result, the balance between plants and zombies had to be restructured—a move that Fan said was definitely worth the effort.[18] Programmers focused on Adventure mode for much of the first year of development. Upon finishing some items ahead of schedule, one of the programmers, Tod Semple, began working on ideas that would later be used for the minigame section. Some ideas for the puzzle mode section would later be tweaked and moved into adventure mode; "Vasebreaker" and "I, Zombie", for example, came from single-level minigame concepts. During testing, Fan found that minigame and puzzle modes seemed to detract from the focus on Adventure mode, so some of the additional modes and minigames were locked requiring advancement within adventure mode to become unlocked.[19] Fan stated that every game he worked on had only him designing the prototype, adding that he used to draw a lot before he made games, where he made pixel art. The final designs of the zombies and the first plants are similar to how they were initially. After searching for an artist, they discovered Rich Werner, who Fan thought clicked with what he intended for the design. He attributed the intrigue of the design to its animation scheme; Tod Semple suggested that they animate it in Flash and export it into the game. Fan worried that this would look like it was cut out from paper, and would resemble South Park too much, but was satisfied in the end, attributing this to Semple and Werner's talents.[19] Fan was most proud of the Tall-nut, Torchwood, and Cob Cannon plants. He explained that the Tall-nut has character, citing its "determined gaze" and how it sheds a single tear when hurt. Laura Shigihara could not stand to see this, and protected it with a protective plant called a Pumpkin, which can protect plants inside it. He felt that the Torchwood - which gives Peashooters flaming ammunition - required players to think of how plants interacted with each other.[18][19] Another favorite plant of Fan's was the Squash, due to how its name suggested its purpose; to squash things.[22] A plant was proposed that is similar to the defensive item Umbrella Leaf, which would be planted above other plants to protect them from airborne zombies. However, it was difficult to visualize their positions.[19] Cultural references[edit] Plants vs. Zombies uses many cultural references in its names of stages and others. The gravestones' inscriptions ("Expired", "Ceased to Exist", "Just Resting", etc.) were taken from Monty Python's "Dead Parrot sketch". Three of the mini-games—"Zombiquarium", "Beghouled" and "Beghouled Twist"—take their names from two other PopCap games (Insaniquarium, Bejeweled and Bejeweled Twist respectively.[19][23] Two levels in "vasebreaker" puzzles, "Scary Potter" and "Ace of Vase", take their names from Harry Potter and Ace of Base. Similarly, the "I, Zombie" (a reference to Isaac Asimov's "I, Robot") puzzles have levels called "Dead Zeppelin" (resembling Led Zeppelin) and "All your brainz r belong to us" (a play on the gaming meme "All your base are belong to us"). The name of the Torchwood plant is a reference to Doctor Who and its spin-off show Torchwood. Originally, the dancing zombie resembled Michael Jackson from the short film "Thriller".[24] Though the Jackson-inspired zombie was present in the game before Jackson's death, the estate of Michael Jackson objected to its inclusion more than a year after his death; PopCap agreed to remove the Jackson-inspired zombie and replaced it with a more generic disco-dancing one for all future patches and releases of the game.[25] Ironically, a "disclaimer" in the game's almanac states "Any resemblance between Dancing Zombie and any persons living or dead is purely coincidental." Some Plants vs. Zombies advertisements parody controversial Evony ads, showing a drooling zombie instead of a voluptuous woman.[26] A planned name was Lawn of the Dead, a pun on the title of the George A. Romero zombie film Dawn of the Dead. For legal reasons it was changed to Plants vs. Zombies.[22] It spent three years in development, and was released for the PC on 5 May 2009.[19] Since it was released, it has been announced for multiple platforms, including PlayStation 3's PlayStation Network, Xbox 360's Xbox Live Arcade digital distribution service, Nintendo DS, and iOS.[27][28] The song "Loonboon" was inspired by composer Laura Shigihara's cat, which they named Metroid. She explained that the stage she was composing for was frantic, so she watched Metroid as he ran around the house, jumping off walls and playing with his toy mouse. "Brainiac Maniac" was inspired by older Capcom games, specifically those in the Mega Man series, describing its songs as melodic and complex. She was inspired to make the Plants vs. Zombies music video by her desire to make a theme song for the game. She specifically chose the Sunflower to be the one singing by wanting to have it communicating with the zombies. She later suggested that it be made into a funny flash video, and Rich Werner and Tod Semple, an artist and programmer, respectively, from PopCap came down and worked on it. Once it was completed after two weeks of work, the PopCap marketing team enjoyed it enough that it used it as a marketing tool.[21] Previously, there were no plans to release the soundtrack as a stand-alone item, but Shigihara stated that she wished to do it, so she thought there was a good chance of it.[29] In November 2010, Shigihara released the soundtrack through her Bandcamp page.[30] Individual tracks are sold at USD1 per track or US$10 for the full album.[31] It comes with a cover art designed by George Fan.[30] Plants vs. Zombies itself was referenced in "The Passing" campaign of Valve's fellow zombie game Left 4 Dead 2, in which the player can stumble upon in-game graffiti attributed to the character of Crazy Dave.[32] A five-level quest chain culminating in a quest entitled "Lawn of the Dead" in the massively multiplayer online game World of Warcraft: Cataclysm is based on Plants vs. Zombies, using Warcraft elements to recreate the gameplay.[33] Blizzard Entertainment had contacted PopCap about the inclusion, and Laura Shigihara was able to record some new music for the Warcraft version of the game.[34] Zomboni is a zombie riding a Zamboni, an ice-cleaning truck used to clean the ice surface in ice hockey. The zombie riding the Zamboni is a Canadian stereotyped zombie. Soundtrack[edit]

The soundtrack for Plants vs. Zombies was composed by Laura Shigihara. It borrows elements from the pop music genre, as well as console chiptunes. Before the inception of Plants vs. Zombies, Director George Fan asked Laura if she would like to compose the music for his next title after following her for some years. She accepted, owing to his creativity. Shigihara described the music as "macabre, yet goofy". Using the night stage as an example, she used a combination of "Big Band" and swing beats with "several haunting and serious melodies". The songs "Loonboon" and "Brainiac Maniac" were written towards the end of production. She stated that these were reactionary songs that she wrote to fit the feel of the game after having played through it twice. She tried to make the game have a Danny Elfman feel to it, while mixing in melodic tunes and funky beats. She describes a song early in the game, which uses marching band percussion and swing beats. She described another one which used techno beats with organic sounds.[29] Shigihara also composed and performed the music video shown during the credits of the game, titled "Zombies on Your Lawn".[35][36] Reception[edit]

[hide]Reception Aggregate scores Aggregator Score GameRankings 88.6% Metacritic 88 Review scores Publication Score 1UP.com A− Edge 9/10 Eurogamer 9/10 GamePro 4.5/5 stars GameSpot 8.5/10 IGN 9.0/10 PC Gamer UK 90% Wired 9/10 Gamezebo 4.5/5 stars Plants vs. Zombies has received a positive reception from critics, garnering an aggregate score of 88/100 from Metacritic and an 89.5% from GameRankings.[37][38] IGN editor Andy J Kolozsy commented that it featured a lot more content than other games in the genre, as well as praising its addictive nature.[39] However, the DS version was criticised for its lower quality graphics and expensive price point.[40] GameSpot editor Chris Watters praised the design of the plants and zombies, as well as the visuals and its overall value. However, he found fault in the learning curve.[41] 1UP editor Alice Liang found the game enjoyable, commenting that the lawnmowers that protect the left side of the screen strikes a good balance between ease-of-use and indepth game play.[23] Edge's review praised PopCap Games for adding an imaginative touch to every little detail of the game. He also credited them for taking the tower defense genre and making it their own.[42] Laura Shigihara's music video also received praise, with Hatfield attributing his interest in the game to the video.[39] Liang also praised the song, asking how anyone could not want Plants vs. Zombies after seeing the video.[23] To date, Plants vs. Zombies is the fastest-selling video game created by PopCap Games.[43] Plants vs. Zombies director George Fan estimated that half of the game's sales are from hardcore gamers.[44] According to PopCap, the iOS release of Plants vs. Zombies sold more than 300,000 copies in the first nine days it was available on the App Store, generating more than $1M in gross sales, and considered it "the top-grossing iPhone launch".[45] Awards[edit] Plants vs. Zombies has been nominated for the "Casual Game of the Year" and "Outstanding Achievement in Game Design" Interactive Achievement Awards from the Academy of Interactive Arts & Sciences.[46] The game received nominations in "Best Game Design", "Innovation", and "Best Download Game" for the Game Developers Choice Awards.[47] Plants vs Zombies was picked by Gamezebo as one of the 'Best games of 2009'.[48] Legacy[edit] A Plants vs. Zombies board game was revealed at the 2011 American International Toy Fair being produced by Screenlife, although the game has since been canceled.[citation needed] A version of the game was added in patch 4.0.3a of World of Warcraft which used similar mechanics as a homage to the popularity of the game. A reward of a non-combat pet singing sunflower is given to those who can beat the minigame.[49] The success of the game has led to the creation of Plants vs. Zombies lottery tickets.[50] True Blood has referenced the game twice in Season 4. In Episode 5, "Me and the Devil", a guard in Bill Compton's office is playing the game on his phone, and in "Cold Grey Light of Dawn", a guard outside of Marnies' cell is playing the game on her iPad. Since the game was partially inspired by the Magic: The Gathering card game, a Magic card called Grave Bramble has been released in the Innistrad expansion. It is a Plant with the Protection from Zombies ability.[51] Zen Pinball 2 for Wii U, PlayStation 3 and PS Vita and Pinball FX 2 on Xbox 360 feature a Plants vs. Zombies pinball table. Plants vs. Zombies Adventures[edit]

In May 2013, a new Facebook version has been released by developer PopCap Games and publisher Electronic Arts. The gameplay is a tower defense game, players no longer have to defend a single home in front of the zombie horde, they will be traveling to new locations and engaged in an altered experience and new characters.[52] The game is available to all users as of May 20, 2013.[53] Sequels[edit]

In late 2012, PopCap announced that they were working on a sequel to Plants vs. Zombies, but the status was in doubt shortly after the announcement when the company went through a period of layoffs. Plants vs. Zombies 2: It's About Time was released August 15, 2013 as a free-to-play title, and will be a time-limited exclusive title for iOS systems before moving to other systems.[54] PopCap and its current owner, Electronic Arts, also announced Plants vs. Zombies: Garden Warfare, a cooperative third-person shooter based on Plants vs. Zombies, for Xbox One, Xbox 360, and Microsoft Windows, also as a sequel. See also[edit]

List of most downloaded Android applications References[edit]

^ Jump up to: a b c d e "Plants vs. Zombies GOTY Edition". Steam. Valve Corporation. Retrieved 2010-08-11. ^ Jump up to: a b Ocampo, Jason (2009-04-04). "No Joke — PopCap Reveals Plants vs. Zombies". IGN. Retrieved 2010-08-11. "PC and Mac initially, with other platforms under consideration." Jump up ^ "PopCap's Plants vs. Zombies Dances Into Retail for PC and Mac". Popcap.com. Retrieved 2010-03-16. ^ Jump up to: a b c "Plants vs. Zombies XBLA Dated, Awesome". IGN. Retrieved 2010-08-18. ^ Jump up to: a b "Plants vs. Zombies for Blackberry Playbook". BlackBerry App World. Research In Motion Limited. 2012-02-16. Retrieved 2012-02-16. ^ Jump up to: a b c "BlackBerry shows off some of its 70,000 new third-party apps, including Skype, Rdio, Kindle, and Whatsapp". The Verge. Retrieved 2013-01-30. ^ Jump up to: a b "Plants vs. Zombies". Popcap.com. Retrieved 2010-07-31. Jump up ^ Bailey, Kat (2010-02-15). "Plants vs. Zombies Now Available on iTunes". 1UP.com. Retrieved 2010-02-15. Jump up ^ computerandvideogames.com Tom Ivan (2011-12-13). "PS Vita News: Plants vs. Zombies confirmed for PS Vita". ComputerAndVideoGames.com. Retrieved 2012-01-19. Jump up ^ "Plants vs. Zombies Now Available". Steam. Valve Corporation. 2009-05-05. Retrieved 2010-08-11. Jump up ^ "PopCap Launches Plants vs. Zombies HD App for iPad". Popcap.com. Retrieved 2010-06-14. Jump up ^ Pereira, Chris (2010-08-23). "Plants vs. Zombies Gets Extra Content and Heads to DS". 1UP.com. Retrieved 2010-08-23. Jump up ^ Pereira, Chris (2011-05-31). "Amazon’s Android Appstore Gets Another Huge Exclusive: Plants vs Zombies". TechCrunch. Retrieved 2011-06-09. Jump up ^ "PopCap Preps Plants vs. Zombies for Xbox LIVE Arcade" (Press release). PopCap Games. 2010-07-19. Retrieved 2010-07-19. Jump up ^ Hatfield, Daemon (2010-08-05). "Plants vs. Zombies XBLA Dead Dated, Awesome". IGN. Retrieved 2010-10-10. Jump up ^ Thompson, Michael (2010-03-19). "Aliens in the garden: the secret origin of Plants vs. Zombies". Ars Technica. Retrieved 2010-03-20. Jump up ^ "Desktop Tower Defense". Desktoptowerdefense.blogspot.com. 2007-04-16. Retrieved 2010-03-16. ^ Jump up to: a b c d e f "Interview with Plants vs. Zombies creator George Fan". Gamezebo. May 22, 2009. Retrieved October 19, 2012. ^ Jump up to: a b c d e f g h i "Flower Defence". Edge. 2009-05-05. Retrieved 2009-09-05. Jump up ^ Smith, Graham (November 2, 2010). "George Fan and his cat on the making of Plants vs. Zombies". PC Gamer. Retrieved October 19, 2012. ^ Jump up to: a b "Game Industry Insider: George Fan". Hobbit Hollow. Retrieved 2009-09-05. ^ Jump up to: a b c "GameArena Interviews George Fan, Plants vs Zombies Man". Game Arena. 2009-06-05. Retrieved 2009-09-05. ^ Jump up to: a b c "Plants vs Zombies Review for the PC from". 1UP.com. Retrieved 2010-03-16. Jump up ^ "Review: Masterful Plants vs. Zombies Proves Less Is More". Wired.com. 2009-05-05. Retrieved 2009-09-05. Jump up ^ Frustick, Russ (2010-07-27). "Michael Jackson Estate Forces 'Plants vs. Zombies' Update". MTV. Retrieved 2010-07-27. Jump up ^ "Plants vs. Zombies Pokes Fun At Cleavage-Filled Evony Ads", The Escapist, 30 Jul 2009 Jump up ^ "Plants VS Zombies Pollinating Other Platforms". Kotaku. 2009-07-10. Retrieved 2009-09-05. Jump up ^ "Plants vs Zombies To Gnaw At Retail, iPhones, Your Chest". Kotaku. 2009-08-21. Retrieved 2009-09-05. ^ Jump up to: a b "Interview: The Terrifying True Story of The Plants vs. Zombies Soundtrack". Gamasutra. 2009-05-19. Retrieved 2009-09-05. ^ Jump up to: a b "Plants vs. Zombies Official Soundtrack now online". Laura Shigihara. 2010-11-22. Retrieved 2011-02-13. Jump up ^ "Plants vs. Zombies Soundtrack". Laura Shigihara. 2010-11-22. Retrieved 2011-02-13. Jump up ^ Good, Owen (2010-04-25). ""The Passing" Also Gives a Shout-Out to Plants vs. Zombies". Kotaku. Retrieved 2010-04-28.The Pogo Zombie is a vaulting zombie in Plants vs. Zombies that jumps over multiple plants and the 19th zombie encountered in Adventure Mode. However, Tall-nuts will stop them from jumping, and Magnet-shrooms will steal their Pogo Sticks.

Contents[hide] Suburban Almanac Entry Overview Appearances Strategies Pogo Party mini-game Gallery Trivia Suburban Almanac EntryEdit Almanac Card Pogo Zombie Pogo Zombie

Pogo Zombie hops to bypass your defenses.

Toughness: medium

Special: hops over plants

Weakness: magnet-shroom

Sproing! Sproing! Sproing! That's the sound of a powerful and effective zombie doing what he does best.

OverviewEdit The Pogo Zombie absorbs 17 normal damage shots and its appearance changes upon an absorption of 9 normal damage shots before dying at 17 normal damage shots.

AppearancesEdit Adventure Mode: 4-8, 4-9, 4-10, 5-4, 5-10 Mini-games: Pogo Party, Dr. Zomboss's Revenge, Heavy Weapon, BOMB All Together!, Zombie Trap Puzzle Mode: Another Chain Reaction, Last Stand: Fog, Last Stand: Roof Survival Mode: Survival: Fog, Survival: Roof, all Survival (Hard) and Survival (Endless) levels Co-op Mode: Co-op Roof, all Co-op Hard levels, Co-op Zomboss, Co-op Endless Others: Versus Mode StrategiesEdit Tall-nuts will stop these zombies cold, and Magnet-shrooms will take away their pogo sticks, causing them to act like a normal zombie. The Squash is a good final line of defense, as it will take the Pogo Zombie out even as it tries to jump over it.

The Split Pea, the Starfruit, the Squash, the Chomper and the Gloom-shroom are also useful against the Pogo Zombie, as the Split Pea and Starfruit shoot behind themselves after the Pogo Zombie jumps over them, and two Gloom-shrooms deal enough damage to kill them while the zombies are attempting to jump. Squashes and Chompers can kill this menace too. This can be more effective than Tall-nuts or Magnet-shrooms, as Magnet-shrooms must recharge before being used again, and Tall-nuts will be eaten after enough zombies bite it. When Pogo Zombies lose their pogo stick, their movement will be very similar to a regular zombie. However, they move slightly faster than a normal zombie would walk, approximately the same as a Flag Zombie.

Note: Chompers will attempt to eat the Pogo Zombie but the zombie would be able to jump first. However it causes a glitch where the Chomper eats what's behind them but sometimes it doesn't.

Pogo Party mini-gameEdit Pogo Party is a mini-game set on the Roof where there are a lot of Pogo Zombies that you will have to stop. You will probably need Tall-nuts and Imitater Tall-nuts, and possibly the Squash and Jalapeno, but just use a regular roof level strategy aside from that.

GalleryEdit Pogo-Zombie Animated Pogo Zombie Pogo party pogozombie hacks modded Pogo Party with lots of Pogo Zombies (modded and hacked) TinyPogo Tiny Pogo Zombies DS Pogo Zombie Pogo Zombie in the DS version Pogo Party Lots of Pogo Zombies at the seed selection Screen for Pogo Party Pogoparty1 Pogo Party in action Pogo no arm A Pogo Zombie without his arm POGOZOMBIEFROZEN Frozen Pogo Zombie POGOZOMBIEFROZEN1 Frozen Pogo Zombie without his arm Pogo no stick A Pogo Zombie without his stick Pogo no arm and stick A Pogo Zombie without his arm and his stick DS Pogo Zombie without Pogo DS Pogo Zombie without pogo stick POGOZOMBIEHEAD Pogo Zombie's head, it will lose its glasses after killed Dead Pogo A dead Pogo Zombie POGOZOMBIEDEADFROZEN A dead frozen Pogo Zombie Pogo Hand A dead Pogo Zombie with two arms

Add a photo to this gallery TriviaEdit The Pogo Zombie is one of the four zombies (along with Dr. Zomboss, the Zomboni and the Balloon Zombie) that can't be affected by butter. This only applies if it still has its pogo stick. Like the Balloon Zombie while it's in the air, it cannot be frozen solid by Ice-shrooms while it has its pogo stick, but can be slowed down. It can also be slowed down by Winter Melons and Snow Peas. This makes it more effective to use Snow Peas and Winter Melons to slow down Pogo zombies, as the Ice-shroom will deal very little damage to Pogo Zombies while Snow Peas and Winter Melons will deal damage to it and slow it down. The Pogo Zombie is the only Jumping Zombie that can jump over plants more than once and will continue on (unless it hits a Tall-nut or its pogo stick gets stolen by a Magnet-shroom). The Pogo Zombie is one of seven zombies to have a mini-game exclusively about them, as it is featured in the Pogo Party, with the other six being Dr. Zomboss in Dr. Zomboss's Revenge, the Zombie Bobsled Team and Zomboni in Bobsled Bonanza, the Snorkel Zombie in Zombiquarium, the Bungee Zombie in Bungee Blitz, and Balloon Zombie in Air Raid. The Pogo Zombie, Jack-in-the-Box Zombie, Flag Zombie, Pole Vaulting Zombie, Dolphin Rider Zombie, Gargantuar, Giga-gargantuar and the Digger Zombie are the only zombies that carry item that is not a shield nor headwear. Before the Pogo Zombie enters the screen, the player can hear the sound of its oily stick. This sound will continue after the Pogo Zombie enters the player's house, except in roof levels and it will even lose its stick. Also, this is one of the few zombies that make a sound before making an entrance. The others are the Digger Zombie, which makes a digging sound, Dolphin Rider Zombie, which is the sound of its Dolphin, and the Balloon Zombie, which is the sound of its Balloon inflating. When a Pogo Zombie is slowed down, its bouncing rate will still be the same, but its speed will become slower, and it also has to bounce two times to jump over a plant when it is frozen. However, for a Cob Cannon, it will have to jump four times due to the larger size. The Pogo Zombie's and Umbrella Leaf's almanac entries, and Jack-in-the-Box Zombie's explosion are the only things in the game that have the word "SPROING!". However, they are not the only instances of which the word "SPROING!" appears. In the achievement name Sproing! Sproing!, "SPROING!" is present twice. The Pogo Zombie is the only zombie to be seen when it enters the chimney. Unless a Tall-nut or a Magnet-shroom is used, the Pogo Zombie will not eat any plants. If timed correctly, on the roof's slope, the Pogo Zombie might have a chance to jump over a Squash and escape without being squashed. The Pogo Zombie is one of the five zombies that has eye wear, the others being the new Dancing Zombie, the Snorkel Zombie, the Zombie Bobsled Team and the Newspaper Zombie. The Pogo Zombie and the Newspaper Zombie have similar eyeglasses. It is unknown how the zombies are able to wear eyeglasses, as they do not have noses or ears to rest them on (the Snorkel Zombies and the Zombie Bobsled Team have straps on their eye wear, which hold them up) If the player looks closely, the Pogo Zombie also wears earrings, but the ears which would be used to support the glasses or the earrings are missing. If the player looks closely, Pogo Zombie has a tattoo on his right arm. Pogo Zombie, Digger Zombie, Balloon Zombie, Dr. Zomboss, Gargantuar, Giga-gargantuar, Imp, and Jack-in-the-Box Zombie are the only zombies that make noise when in the lawn. The Pogo Zombie will lose his pogo stick upon climbing a ladder placed on a Tall-nut. If a Pogo Zombie gets hit by a catapult plant on the Nintendo DS version of Plants vs. Zombies and he still has his pogo stick, it may get hit at the bottom of the pogo stick instead of his head. It is the only zombie carrying a metal object that is a Vaulting Zombie. The Pogo Stick is the only vaulting equipment that could be damaged by projectile plants. Pogo Zombie is the only Vaulting Zombie that is immune to Potato Mines if its pogo stick is not stolen by a Magnet-shroom or lost by a Tall-nut. When the Pogo Zombie is slowed it will take two jumps to get over a regular Plant and four jumps to get over a Cob Cannon. Spikeweeds and Spikerocks will damage Pogo Zombies while they are still on their pogo sticks, unless they are Pumpkined. It's odd that the almanac entry doesn't state that Tall-nut is its weakness. Zombies (Plants vs. Zombies) Day Zombie · Flag Zombie · Conehead Zombie · Pole Vaulting Zombie · Buckethead Zombie Night Newspaper Zombie · Screen Door Zombie · Football Zombie · Dancing Zombie · Backup Dancer Pool Ducky Tube Zombie · Snorkel Zombie · Zomboni · Zombie Bobsled Team · Dolphin Rider Zombie Fog Jack-in-the-Box Zombie · Balloon Zombie · Digger Zombie · Pogo Zombie · Zombie Yeti Roof Bungee Zombie · Ladder Zombie · Catapult Zombie · Gargantuar · Imp · Dr. Zomboss ZomBotany Peashooter Zombie · Wall-nut Zombie · Gatling Pea Zombie · Tall-nut Zombie · Squash Zombie · Jalapeno Zombie Others Trash Can Zombie · Target Zombie · Giga-gargantuar · Giga-Football Zombie · Baseball Zombie · Catapult Baseball Zombie Special Invisible Zombies · Little Zombies · Dolphin · Zombie Worm · Chinese Zombies · Queen Zombie · Zombatar · Sunflower Zombie · Vampire Imp Gallery Gallery of Zombies Start a Discussion Discussions about Pogo Zombie

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Categories: Featured Articles Zombies Fog Fog Encountered Zombies Vaulting Zombies Zombies with "Medium" toughness Plants vs. Zombies Plants vs. Zombies Zombies Add category Read more Jump up ^ Smith, Quentin (2010-09-20). "Plants Vs. Zombies Quest In WoW: Cataclysm". Rock Paper Shotgun. Retrieved 2010-09-20. Jump up ^ Westbrook, Logan (2010-09-22). "PopCap Delighted With WoW's Plants vs. Zombies Tribute". The Escapist. Retrieved 2010-09-22. Jump up ^ "Laura Shigihara - Lyrics". Laura Shigihara. Retrieved 2010-08-18. Jump up ^ "Plants vs Zombies Music Video". PlantsVsZombies channel (PopCap Games). Retrieved 2010-08-18. Jump up ^ "Plants vs. Zombies". Metacritic. 2009-05-05. Retrieved 2010-03-16. Jump up ^ "Plants vs. Zombies". GameRankings. Retrieved 2010-03-16. ^ Jump up to: a b Hatfield, Daemon (2009-05-05). "Plants vs. Zombies Review - PC Review at IGN". Pc.ign.com. Retrieved 2010-06-30. Jump up ^ Daemon Hatfield. "Plants vs. Zombies DS Review - Nintendo DS Review at IGN". Uk.ds.ign.com. Retrieved 2012-01-19. Jump up ^ Watters, Chris (2009-05-05). "Plants vs. Zombies Review for PC". GameSpot. Retrieved 2010-03-16. Jump up ^ "Review: Plants Vs Zombies". Edge Online. 2009-05-05. Retrieved 2010-03-16. Jump up ^ "Plants vs. Zombies is PopCap's fastest-selling game". Joystiq. 2009-05-20. Retrieved 2009-09-05. Jump up ^ "Analysis: The Universal (Brain-Eating) Appeal Of Plants Vs. Zombies". Gamasutra. 2009-05-20. Retrieved 2009-09-05. Jump up ^ Faylor, Chris (2010-02-25). "Plants vs. Zombies iPhone Sets New iTunes App Store Record, Breaks $1M in Nine Days". Shacknews. Retrieved 2010-02-25. Jump up ^ "13th Annual Interactive Achievement Awards Finalists" (PDF). Academy of Interactive Arts & Sciences. 2010-01-21. Retrieved 2010-01-24. Jump up ^ "Uncharted 2, Flower, Assassin's Creed II Lead Finalists for the Tenth Annual Game Developers Choice Awards". PR Newswire. 2010-01-19. Retrieved 2010-01-24. Jump up ^ "Gamezebo's Best of 2009". Gamezebo. 2009-12-28. Jump up ^ Atreides, Jarl (2011-06-07). "Lawn of the Dead". Wowhead. Retrieved 2011-06-07. Jump up ^ "New Mexico Lottery". Jump up ^ "Scary Stories, Part 2". Wizards of the Coast. 2011-09-26. Retrieved 2012-04-23. Jump up ^ "Plants vs. Zombies Adventures Announced for Facebook". Jump up ^ "Plants vs. Zombies Adventures will launch on Facebook on May 20". Jump up ^ Yannick, LeJacq (May 6, 2013). "'Plants vs. Zombies' sequel shambling toward release in July". NBC News. Retrieved May 20, 2013.