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For the history of evolutionary biology, see History of evolutionary thought. Evolutionary thought, the idea that species change over time has roots in antiquity in the ideas of the Greeks, Romans, Chinese and Muslims

This timeline of the evolution of life outlines the major events in the development of life on the planet Earth. Life is a state that distinguishes Organisms from non-living objects such as non-life and dead organisms being manifested by growth through Metabolism EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 For a thorough explanatory context, see the history of Earth, and geologic time scale. The history of Earth covers approximately 46 billion years (4567000000 years from Earth ’s formation out of the Solar nebula to the present The geologic time scale is a chronologic schema (or idealized Model) relating Stratigraphy to time that is used by Geologists and other The dates given in this article are estimates based on scientific evidence.

In biology, evolution is the process by which populations of organisms acquire and pass on novel traits from generation to generation. Foundations of modern biology There are five unifying principles eVolution is the third Album by eLDee, it was due to be released in 2008 A trait is a distinct phenotypic character of an organism that may be inherited environmentally determined or somewhere in between Its occurrence over large stretches of time explains the origin of new species and ultimately the vast diversity of the biological world. Speciation is the Evolutionary process by which new biological Species arise Contemporary species are related to each other through common descent, products of evolution and speciation over billions of years. A group of organisms is said to have common descent if they have a common Ancestor. Speciation is the Evolutionary process by which new biological Species arise

Contents

Basic timeline

Life on Earth
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Formation
of Earth
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Atmospheric oxygen
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Modern-looking
humans
Axis scale: millions of years ago. In the Natural sciences, Abiogenesis, or origin of life, is the study of how Life on Earth emerged from Inanimate Organic Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex Multicellular organisms are Organisms consisting of more than one cell, and having Differentiated cells that perform specialized functions The embryophytes are the most familiar group of Plants They include Trees Flowers Ferns Mosses and various other green Mammals ( class Mammalia) are a class of Vertebrate Animals characterized by the presence of Sweat glands, including sweat glands The flowering plants or angiosperms ( Angiospermae or Magnoliophyta) are the most widespread group The Late Heavy Bombardment (commonly referred to as the lunar cataclysm, or LHB) is a period of time approximately 3800 to 4100 million years ago ( mya The Ediacara (ˌiːdɪˈækərə formerly Vendian) biota are ancient lifeforms of the Ediacaran Period which represent the earliest known complex The Cambrian explosion or Cambrian radiation was the seemingly rapid appearance of most major groups of complex Animals around, as evidenced by the
Dates prior to 1 billion years ago are speculative.

The basic timeline is a 4.6 billion year old Earth, with (very approximately):

Detailed timeline

Note that Ma means "million years ago".

Hadean eon

3800 Ma and earlier. The Hadean (ˈheɪdiən is the geologic eon before the Archean.

DateEvent
4567. 17 MaThe planet Earth forms from the accretion disc revolving around the young Sun. EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 An accretion disc (or accretion disk) is a structure (often a Circumstellar disk) formed by diffuse material in orbital motion around a central body The Sun (Sol is the Star at the center of the Solar System.
4533 MaThe planet Earth and the planet Theia collide, sending countless moonlets into orbit around the young Earth. Theia is the Hypothetical planet that according to the Giant impact hypothesis of the Moon 's formation collided with Earth over four billion These moonlets eventually coalesce to form the Moon. The gravitational pull of the new Moon stabilises the Earth's fluctuating axis of rotation and sets up the conditions for the formation of life. A rotation is a movement of an object in a circular motion A two- Dimensional object rotates around a center (or point) of rotation [1]
4100 MaThe surface of the Earth cools enough for the crust to solidify. In Geology, a crust is the outermost solid shell of a planet or moon The atmosphere and the oceans form. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five An ocean (from Greek, ''Okeanos'' (Oceanus) is a major body of saline water, and a principal component of the Hydrosphere. [2]PAH infall, and Iron-Sulfide synthesis along deep ocean platelet boundaries, may have led to the RNA world of competing metabolising organic compounds. The PAH world hypothesis is a biological Hypothesis that proposes that the use of Polycyclic aromatic hydrocarbons (PAH was a means for a pre- RNA The RNA world hypothesis proposes that a world filled with life based on Ribonucleic acid (RNA predated current life based on Deoxyribonucleic acid (DNA
Between 4500 and 2500 MaThe earliest life appears, possibly derived from self-reproducing RNA molecules. In the Natural sciences, Abiogenesis, or origin of life, is the study of how Life on Earth emerged from Inanimate Organic The RNA world hypothesis proposes that a world filled with life based on Ribonucleic acid (RNA predated current life based on Deoxyribonucleic acid (DNA Ribonucleic acid ( RNA) is a Nucleic acid that consists of a long chain of Nucleotide units The replication of these organisms requires resources like energy, space, and smaller building blocks, which soon become limited, resulting in competition. Natural selection favours those molecules which are more efficient at replication. Natural selection is the process by which favorable Heritable traits become more common in successive Generations of a Population of DNA molecules then take over as the main replicators. Deoxyribonucleic acid ( DNA) is a Nucleic acid that contains the genetic instructions used in the development and functioning of all known They soon develop inside enclosing membranes which provide a stable physical and chemical environment conducive to their replication: proto-cells. The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called
3900 MaLate Heavy Bombardment: peak rate of impact events upon the inner planets by meteors. The Late Heavy Bombardment (commonly referred to as the lunar cataclysm, or LHB) is a period of time approximately 3800 to 4100 million years ago ( mya See also Impact crater An impact event is the Collision of a large Meteoroid, Asteroid or Comet (generically This constant disturbance probably obliterated any life that had already evolved, as the oceans boiled away completely; conversely, life may have been transported to Earth by a meteor. In Ecology, a disturbance is a temporary change in average environmental conditions that causes a pronounced change in an ecosystem Panspermia ( Gk. πάς/πάν (pas/pan all and σπέρμα ( sperma, seed is the Hypothesis that "seeds" of Life exist already [3]
Somewhere between 3900 - 2500 MaCells resembling prokaryotes appear. The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called The prokaryotes (proʊˈkærioʊts singular prokaryote /proʊˈkæriət/ are a group of Organisms that lack a Cell nucleus (= karyon or any other These first organisms are chemoautotrophs: they use carbon dioxide as a carbon source and oxidize inorganic materials to extract energy. Chemotrophs are organisms that obtain Energy by the Oxidation of Electron donating Molecules in their environments Carbon dioxide ( Chemical formula:) is a Chemical compound composed of two Oxygen Atoms covalently bonded to a single Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 Redox (shorthand for reduction-oxidation reaction describes all Chemical reactions in which atoms have their Oxidation number ( Oxidation state Later, prokaryotes evolve glycolysis, a set of chemical reactions that free the energy of organic molecules such as glucose. See also Gluconeogenesis, which carries out a process wherein glucose is synthesized rather than catabolized Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology. Glycolysis generates ATP molecules as short-term energy currency, and ATP continue to be used in almost all organisms, unchanged, to this day. Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy

Archean eon

3800 Ma - 2500 Ma

DateEvent
3500 MaLifetime of the last universal ancestor; the split between the bacteria and the neomura occurs. The last universal ancestor ( LUA) also called the last universal common ancestor ( LUCA) the cenancestor or "number one" The Bacteria ( singular: bacterium) are a large group of unicellular Microorganisms Typically a few Micrometres in length bacteria have Neomura is a speculative Clade composed of the two domains of life of Archaea and Eukarya.

Bacteria develop primitive forms of photosynthesis which at first do not produce oxygen. Photosynthesis is a Metabolic pathway that converts Light Energy into Chemical energy. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the These organisms generate ATP by exploiting a proton gradient, a mechanism still used in virtually all organisms. Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy In Cellular biology, an electrochemical gradient is a spatial variation of both Electrical potential and chemical Concentration across a membrane

3000 Ma
Photosynthesizing cyanobacteria evolve; they use water as a reducing agent, thereby producing oxygen as waste product. Cyanobacteria, also known as blue-green algae, blue-green bacteria or Cyanophyta, is a phylum of Bacteria that obtain their energy A reducing agent (also called a reductant or reducer) is the element or a compound in a Redox (reduction-oxidation reaction (see Electrochemistry Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the The oxygen initially oxidizes dissolved iron in the oceans, creating iron ore. Iron ores are rocks and Minerals from which Metallic Iron can be economically extracted The oxygen concentration in the atmosphere subsequently rises, acting as a poison for many bacteria. An atmosphere (from Greek ατμός - atmos, " Vapor " + σφαίρα - sphaira, " Sphere " The moon is still very close to the earth and causes tides 1000 feet high. Characteristics A tide is a repeated cycle of sea level changes in the following stages Over several hours the water rises or advances up a beach in the flood The earth is continually wracked by hurricane force winds. These extreme mixing influences are thought to stimulate evolutionary processes. (See Oxygen Catastrophe)

Proterozoic eon

2500 Ma - 542 Ma

DateEvent
By 2100 MaEukaryotic cells appear. The Oxygen Catastrophe was a massive environmental change believed to have happened during the Siderian period at the beginning of the Paleoproterozoic The Proterozoic (ˌproʊtərəˈzoʊɪk is a geological eon representing a period before the first abundant complex life on Earth. Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex Eukaryotes contain membrane-bound organelles with diverse functions, probably derived from prokaryotes englufing each other via phagocytosis. In Cell biology, an organelle (pronunciation /ɔː(rgəˡnɛl/ is a specialized subunit within a cell that has a specific function and is usually separately enclosed The prokaryotes (proʊˈkærioʊts singular prokaryote /proʊˈkæriət/ are a group of Organisms that lack a Cell nucleus (= karyon or any other Phagocytosis is the cellular process of engulfing solid particles by the Cell membrane to form an internal Phagosome, or "food vacuole
By 1200 MaSexual reproduction evolves, increasing the rate of evolution. The Evolution of sexual reproduction is a major puzzle The first Fossilized evidence of sexually reproducing Organisms is from Eukaryotes of the Stenian [4]
1200 MaSimple multicellular organisms evolve, mostly consisting of cell colonies of limited complexity. Multicellular organisms are Organisms consisting of more than one cell, and having Differentiated cells that perform specialized functions The first Organisms that existed are believed to have been Unicellular.
850–630 MaA global glaciation may have reduced the diversity of life. The Snowball Earth Hypothesis as it was originally proposed]] Evidence The Snowball Earth hypothesis was originally devised to explain the apparent presence of Opinion is divided on whether it increased or decreased the rate of evolution.
580-542 MaThe Ediacaran biota represent the first large, complex multicellular organisms - although their affinities remain a subject of debate. The Ediacara (ˌiːdɪˈækərə formerly Vendian) biota are ancient lifeforms of the Ediacaran Period which represent the earliest known complex
580–500 MaMost modern groups begin to appear in the fossil record during the Cambrian explosion. The Cambrian explosion or Cambrian radiation was the seemingly rapid appearance of most major groups of complex Animals around, as evidenced by the
Around 540 MaThe accumulation of atmospheric oxygen allows the formation of an ozone layer. The photochemical mechanisms that give rise to the ozone layer were worked out by the British physicist Sidney Chapman in 1930 This blocks ultraviolet radiation, permitting the colonisation of the land. Ultraviolet ( UV) light is Electromagnetic radiation with a Wavelength shorter than that of Visible light, but longer than X-rays

Phanerozoic eon

542 Ma - present

The Phanerozoic eon, literally the "period of well-displayed life", marks the appearance in the fossil record of abundant, shell-forming and/or trace-making organisms. The Phanerozoic (occasionally Phanaerozoic) Eon is the current eon in the Geologic timescale, and the one during which abundant animal life has existed It is subdivided into three eras, the Paleozoic, Mesozoic and Cenozoic, which are divided by major mass extinctions. An extinction event (also known as mass extinction; extinction-level event, ELE is a sharp decrease in the number of Species in a relatively short period

Paleozoic era

542 Ma - 251. The Paleozoic or Palaeozoic Era (from the Greek palaio (παλαιο "old" and zoe (ζωη "life" meaning "ancient life" 0 Ma


DateEvent
530 MaThe first known footprints on land date to 530 Ma, indicating that early animal explorations may have predated the development of terrestrial plants. [5]
475 MaThe first primitive plants move onto land,[6] having evolved from green algae living along the edges of lakes. Plants are living Organisms belonging to the kingdom Plantae. [7] They are accompanied by fungi, which may have aided the colonisation of land through symbiosis. A fungus (ˈfʌŋgəs is a eukaryotic Organism that is a member of the kingdom Fungi (ˈfʌndʒaɪ This article is about the biological phenomenon for other uses see Symbiosis (disambiguation The term symbiosis (from the Greek
363 MaBy the start of the Carboniferous period, the Earth begins to be recognisable. The Carboniferous is a geologic period and system that extends from the end of the Devonian period about 359 Insects roamed the land and would soon take to the skies; sharks predated the oceans,[8] and vegetation covered the land, with seed-bearing plants and forests soon to flourish. Insects ( Class Insecta) are a major group of Arthropods and the most diverse group of Animals on the Earth with over a million described Sharks ( Superorder Selachimorpha) are a type of Fish with a full cartilaginous Skeleton and a highly streamlined body

Four-limbed tetrapods gradually gain adaptations which will help them occupy a terrestrial life-habit. Tetrapods ( Greek τετραποδη tetrapoda, Latin Quadruped, "four-footed" are Vertebrate Animals

251. 4MaThe Permian-Triassic extinction event eliminates over 95% of species. The Permian–Triassic (P–Tr extinction event, informally known as the Great Dying, was an Extinction event that occurred, and 70 percent of terrestrial This "clearing of the slate" may have led to an ensuing diversification.

Mesozoic era

DateEvent
From 251. The Mesozoic Era is one of three geologic eras of the Phanerozoic eon. 4 MaThe Mesozoic Marine Revolution begins: increasingly well-adapted and diverse predators pressurise sessile marine groups; the "balance of power" in the oceans shifts dramatically as some groups of prey adapt more rapidly and effectively than others. The Mesozoic marine revolution ( MMR) was a fundamental restructuring of marine ecosystems during the Mesozoic period caused by increased predation pressure
220 Ma
Eoraptor, an early dinosaur.
Eoraptor, an early dinosaur.

Gymnosperm forests dominate the land; herbivores grow to huge sizes in order to accommodate the large guts necessary to digest the nutrient-poor plants. Gymnosperm (Gymnospermae are a group of Spermatophyte seed-bearing Plants with Ovules on the edge or blade of an open Sporophyll, which are

200 MaThe first accepted evidence for viruses (at least, the group Geminiviridae) exists. A virus (from the Latin virus meaning Toxin or Poison) is a sub-microscopic infectious agent that is unable Geminiviruses are Plant viruses which have Ambisense single-stranded Circular DNA genomes and are members of class II of the Baltimore classification [9] Viruses are still poorly understood and may have arisen before "life" itself, or may be a more recent phenomenon.
130 MaThe rise of the Angiosperms: These flowering plants boast structures that attract insects and other animals to spread pollen. The flowering plants or angiosperms ( Angiospermae or Magnoliophyta) are the most widespread group A flower, also known as a bloom or Blossom, is the reproductive structure found in Flowering plants (plants of the division Magnoliophyta, also Pollen is a fine to coarse powder consisting of microgametophytes ( pollen grains) which produce the male Gametes (sperm cells of This innovation causes a major burst of animal evolution through co-evolution. In a broad sense biological co-evolution is "the change of a biological object triggered by the change of a related object"

Cenozoic era

65. The Cenozoic (also Caenozoic or Cainozoic) Era (ˌsiːnəˈzoʊɪk/ /ˌsɛn- (meaning "new life" ( Greek ( kainos) "new" 5 Ma - present

DateEvent
65. 5 Ma
An asteroid impact probably wiped out half of all animals species 65½ million years ago. Other life forms became extinct as well.

The Cretaceous–Tertiary extinction event eradicates about half of all animal species, including all non-avian dinosaurs. The Cretaceous–Tertiary extinction event, which occurred approximately ( Ma) was a large-scale mass extinction of animal and plant species in a geologically

35 MaGrasses evolve from among the angiosperms; grassland dominates many terrestrial ecosystems. Poaceae or Gramineae is a family in the Class Liliopsida of the flowering plants. The flowering plants or angiosperms ( Angiospermae or Magnoliophyta) are the most widespread group
14,000 years agoThe term Anthropocene has been used to describe the period of time during which humans have had a major impact on the planet and its diversity of life. The term Anthropocene is used by some scientists to describe the most recent period in the Earth 's history Human beings, humans or man (Origin 1590–1600 L homō man OL hemō the earthly one (see Humus Its beginning is marked by the megafaunal extinction in the Americas which signify the onset of the Holocene extinction event. The Holocene extinction event is the widespread ongoing Mass extinction of Species during the modern Holocene epoch. Fierce debate rages about the influence of man in the initiation of this extinction.
Present dayWith a human population approaching 6. The world population is the total number of living Humans on Earth at a given time 67 billion,[10] the impact of humanity is felt in all corners of the globe. Overfishing, anthropogenic climate change, industrialisation, intensive agriculture, clearance of rain forests and other activities contribute to a dramatically rising extinction rate. Overfishing occurs when Fishing activities reduce fish stocks below an acceptable level Anthropogenic effects processes objects or materials are those that are derived from Human activities as opposed to those occurring in Natural environments without is a process of social and economic change whereby a human group is transformed from a Pre-industrial society into an industrial one [11] If current rates continue, humanity will have seen the eradication of one-half of Earth's biodiversity over the next hundred years. [12]

See also

Further reading

References

  1. ^ Planetary Science Institute page on the Giant Impact Hypothesis. Plants have evolved through increasing levels of complexity, from the earliest Algal mats through Bryophytes Lycopods Ferns An extinction event (also known as mass extinction; extinction-level event, ELE is a sharp decrease in the number of Species in a relatively short period The geologic time scale is a chronologic schema (or idealized Model) relating Stratigraphy to time that is used by Geologists and other The history of Earth covers approximately 46 billion years (4567000000 years from Earth ’s formation out of the Solar nebula to the present Natural history is the Scientific research of Plants or Animals leaning more towards the Observational than Experimental methods Sociocultural evolution(ism is an umbrella term for theories of cultural evolution and Social evolution, describing how Cultures and societies The timeline of human evolution outlines the major events in the development of Human Species, and the Evolution of humans' Ancestors It includes This article attempts to place key plant innovations in a geological context The Ancestor's Tale (subtitled A Pilgrimage to the Dawn of Life) is a 2004 Popular science Book by Richard Dawkins Clinton Richard Dawkins, FRS, FRSL (born 26 March 1941 is a British ethologist, evolutionary biologist, and Popular science Hartmann and Davis belonged to the PSI. This page also contains several paintings of the impact by Hartmann himself.
  2. ^ "However, once the Earth cooled sufficiently, sometime in the first 700 million years of its existence, clouds began to form in the atmosphere, and the Earth entered a new phase of development. " How the Oceans Formed (URL accessed on January 9, 2005)
  3. ^ " Between about 3. Events 475 - Byzantine Emperor Zeno is forced to flee his capital at Constantinople. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. 8 billion and 4. 5 billion years ago, no place in the solar system was safe from the huge arsenal of asteroids and comets left over from the formation of the planets. Sleep and Zahnle calculate that Earth was probably hit repeatedly by objects up to 500 kilometers across" Geophysicist Sleep: Martian underground may have harbored early life (URL accessed on January 9, 2005)
  4. ^ "'Experiments with sex have been very hard to conduct,' Goddard said. Events 475 - Byzantine Emperor Zeno is forced to flee his capital at Constantinople. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. 'In an experiment, one needs to hold all else constant, apart from the aspect of interest. This means that no higher organisms can be used, since they have to have sex to reproduce and therefore provide no asexual control. '
    Goddard and colleagues instead turned to a single-celled organism, yeast, to test the idea that sex allows populations to adapt to new conditions more rapidly than asexual populations. " Sex Speeds Up Evolution, Study Finds (URL accessed on January 9, 2005)
  5. ^ "The oldest fossils of footprints ever found on land hint that animals may have beaten plants out of the primordial seas. Events 475 - Byzantine Emperor Zeno is forced to flee his capital at Constantinople. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. Lobster-sized, centipede-like or slug like animals such as Protichnites and Climactichnites made the prints wading out of the ocean and scuttling over sand dunes about 530 million years ago. Protichnites is a genus of Trace fossil consisting of the imprints made by the walking activity of Arthropods It is likely that more than one type of arthropod Climactichnites is an enigmatic late Cambrian fossil formed on sandy tidal flats around. Previous fossils indicated that animals didn't take this step until 40 million years later. " Oldest fossil footprints on land
  6. ^ "The oldest fossils reveal evolution of non-vascular plants by the middle to late Ordovician Period (~450-440 m. y. a. ) on the basis of fossil spores" Transition of plants to land
  7. ^ "The land plants evolved from the algae, more specifically green algae, as suggested by certain common biochemical traits" The first land plants
  8. ^ "The ancestry of sharks dates back more than 200 million years before the earliest known dinosaur. Introduction to shark evolution, geologic time and age determination
  9. ^ "Viruses of nearly all the major classes of organisms—animals, plants, fungi and bacteria/archaea—probably evolved with their hosts in the seas, given that most of the evolution of life on this planet has occurred there. This means that viruses also probably emerged from the waters with their different hosts, during the successive waves of colonisation of the terrestrial environment. " Origins of Viruses (URL accessed on January 9, 2005)
  10. ^ An United States Census Bureau estimate of the number of people alive on Earth at any given moment. Events 475 - Byzantine Emperor Zeno is forced to flee his capital at Constantinople. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. The United States Census Bureau (officially Bureau of the Census as defined in Title) is the government agency that is responsible for the United States Census United States census bureau
  11. ^ The American Museum of Natural History National Survey Reveals Biodiversity Crisis (URL accessed on February 23, 2006)
  12. ^ E. O. Wilson, Harvard University, The Future of Life (2002)

External links

Events 1455 - Traditional date for the publication of the Gutenberg Bible, the first Western Book printed from Movable Year 2006 ( MMVI) was a Common year starting on Sunday of the Gregorian calendar. Edward Osborne Wilson (born June 10, 1929) is an American biologist researcher ( Sociobiology, Biodiversity) theorist (
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