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Encyclopedia > Evidence of common descent
Part of the Biology series on
Evolution
Mechanisms and processes

Adaptation
Genetic drift
Gene flow
Mutation
Natural selection
Speciation For the song by Girls Aloud see Biology (song) Biology studies the variety of life (clockwise from top-left) E. coli, tree fern, gazelle, Goliath beetle Biology (from Greek: βίος, bio, life; and λόγος, logos, speech lit. ... This article is about evolution in biology. ... Image File history File links Tree_of_life. ... For other uses, see Adaptation (disambiguation). ... In population genetics, genetic drift is the statistical effect that results from the influence that chance has on the success of alleles (variants of a gene). ... In population genetics, gene flow (also known as gene migration) is the transfer of alleles of genes from one population to another. ... For linguistic mutation, see Apophony. ... For other uses, see Natural selection (disambiguation). ... Charles Darwins first sketch of an evolutionary tree from his First Notebook on Transmutation of Species (1837) Speciation is the evolutionary process by which new biological species arise. ...

Research and history

Evidence
Evolutionary history of life
History
Modern synthesis
Social effect / Objections The evolutionary history of life and the origin of life are fields of ongoing geological and biological research. ... Evolutionary thought has roots in antiquity as philosophical ideas conceived during the Ancient Greek and Roman eras, but until the 18th century, biological thought was dominated by essentialism, the idea that living forms are static and unchanging in time. ... The modern evolutionary synthesis refers to a set of ideas from several biological specialities that were brought together to form a unified theory of evolution accepted by the great majority of working biologists. ... The theory of transmutation had early origins in the speculations and hypotheses of Erasmus Darwin, and Jean-Baptiste Lamarck. ... There have been numerous objections to evolution since alternative evolutionary ideas came to be hotly debated around the start of the nineteenth century. ...

Evolutionary biology fields

Cladistics
Ecological genetics
Evolutionary development
Human evolution
Molecular evolution
Phylogenetics
Population genetics
It has been suggested that Clade be merged into this article or section. ... Ecological genetics is the study of genetics (itself a field of biology) from an ecological perspective. ... Evolutionary developmental biology (evolution of development or informally, evo-devo) is a field of biology that compares the developmental processes of different animals in an attempt to determine the ancestral relationship between organisms and how developmental processes evolved. ... For the history of humans on Earth, see History of the world. ... Molecular evolution is the process of the genetic material in populations of organisms changing over time. ... Phylogenetic groups, or taxa, can be monophyletic, paraphyletic, or polyphyletic. ... Population genetics is the study of the distribution of and change in allele frequencies under the influence of the four evolutionary forces: natural selection, genetic drift, mutation, and migration. ...

Biology Portal · v  d  e 
While on board HMS Beagle, Charles Darwin collected numerous specimens, many new to science, which supported his later theory of evolution by natural selection.

The wide range of evidence of common descent of living things strongly indicates the occurrence of evolution and provides a wealth of information on the natural processes by which the variety of life on Earth developed, supporting the modern evolutionary synthesis. Image File history File links Download high resolution version (1235x821, 71 KB) Summary HMS Beagle in the seaways of Tierra del Fuego, painting by Conrad Martens during the voyage of the Beagle (1831-1836), from The Illustrated Origin of Species by Charles Darwin, abridged and illustrated by Richard Leakey ISBN... Image File history File links Download high resolution version (1235x821, 71 KB) Summary HMS Beagle in the seaways of Tierra del Fuego, painting by Conrad Martens during the voyage of the Beagle (1831-1836), from The Illustrated Origin of Species by Charles Darwin, abridged and illustrated by Richard Leakey ISBN... HMS Beagle was a Cherokee class 10-gun brig of the Royal Navy, named after the beagle, a breed of dog. ... For other people of the same surname, and places and things named after Charles Darwin, see Darwin. ... For other uses, see Natural selection (disambiguation). ... This article is about evolution in biology. ... This article is about Earth as a planet. ... The modern evolutionary synthesis refers to a set of ideas from several biological specialities that were brought together to form a unified theory of evolution accepted by the great majority of working biologists. ...


Fossils are important for estimating when various lineages developed. As fossilization is an uncommon occurrence, usually requiring hard body parts and death near a site where sediments are being deposited, the fossil record only provides sparse and intermittent information about the evolution of life. Evidence of organisms prior to the development of hard body parts such as shells, bones and teeth is especially scarce, but exists in the form of ancient microfossils, as well as impressions of various soft-bodied organisms. For other uses, see Fossil (disambiguation). ... This article or section cites very few or no references or sources. ... This article is about evolution in biology. ... The scientific method or process is fundamental to the scientific investigation and acquisition of new knowledge based upon physical evidence. ... Domains and Kingdoms Nanobes Acytota Cytota Bacteria Neomura Archaea Eukaryota Bikonta Apusozoa Rhizaria Excavata Archaeplastida Rhodophyta Glaucophyta Plantae Heterokontophyta Haptophyta Cryptophyta Alveolata Unikonta Amoebozoa Opisthokonta Choanozoa Fungi Animalia An ericoid mycorrhizal fungus Life on Earth redirects here. ... For other uses of the term, see Fossil (disambiguation) Fossils are the mineralized remains of animals or plants or other artifacts such as footprints. ...


Comparison of the genetic sequence of organisms has revealed that organisms that are phylogenetically close have a higher degree of sequence similarity than organisms that are phylogenetically distant. Further evidence for common descent comes from genetic detritus such as pseudogenes, regions of DNA that are orthologous to a gene in a related organism, but are no longer active and appear to be undergoing a steady process of degeneration. Since metabolic processes do not leave fossils, research into the evolution of the basic cellular processes is also done largely by comparison of existing organisms. Many lineages diverged at different stages of development, so it is theoretically possible to determine when certain metabolic processes appeared by comparing the traits of the descendants of a common ancestor. Phylogenetic groups, or taxa, can be monophyletic, paraphyletic, or polyphyletic. ... A group of organisms is said to have common descent if they have a common ancestor. ... A pseudogene is a nucleotide sequences that is similar to a normal gene, but is not expressed as a functional protein. ... In biology, homology is any similarity between structures that is due to their shared ancestry. ... Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ...

Contents

Evidence from paleontology

An insect trapped in amber.

When organisms die, they often decompose rapidly or are consumed by scavengers, leaving no permanent evidences of their existence. However, occasionally, some organisms are preserved. The remains or traces of organisms from a past geologic age embedded in rocks by natural processes are called fossils. They are extremely important for understanding the evolutionary history of life on Earth, as they provide direct evidence of evolution and detailed information on the ancestry of organisms. Paleontology is the study of past life based on fossil records and their relations to different geologic time periods. Download high resolution version (980x1360, 144 KB) Resin This image shows resin with an insect (an ant?). Photographer André Karwath aka Aka Date 2005-04-23 License GNU FDL Camera data Camera Nikon D70 Lens Tamron SP AF 90mm/2. ... Download high resolution version (980x1360, 144 KB) Resin This image shows resin with an insect (an ant?). Photographer André Karwath aka Aka Date 2005-04-23 License GNU FDL Camera data Camera Nikon D70 Lens Tamron SP AF 90mm/2. ... For other uses, see Amber (disambiguation). ... For other uses, see Decomposition (disambiguation). ... For a person who scavenges, see Waste picker. ... A fossilized dinosaur footprint at Clayton Lake State Park, New Mexico. ... // For other uses, see time scale. ... This article is about the geological substance. ... For other uses, see Fossil (disambiguation). ... Life on Earth  â€¢  â€¢  | Axis scale: millions of years ago. ... Paleontology, palaeontology or palæontology (from Greek: paleo, ancient; ontos, being; and logos, knowledge) is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. ...


For fossilization to take place, the traces and remains of organisms must be quickly buried so that weathering and decomposition do not occur. Skeletal structures or other hard parts of the organisms are the most commonly occurring form of fossilized remains (Paul, 1998), (Behrensmeyer, 1980) and (Martin, 1999). There are also some trace "fossils" showing moulds, cast or imprints of some previous organisms. Weathering is the decomposition of rocks, soils and their minerals through direct contact with the Earths atmosphere. ... One half of a bronze mold for casting a socketed spear head dated to the period 1400-1000 BC. There are no known parallels for this mold. ...


As an animal dies, the organic materials gradually decay, such that the bones become porous. If the animal is subsequently buried in mud, mineral salts will infiltrate into the bones and gradually fill up the pores. The bones will harden into stones and be preserved as fossils. This process is known as petrification. If dead animals are covered by wind-blown sand, and if the sand is subsequently turned into mud by heavy rain or floods, the same process of mineral infiltration may occur. Apart from petrification, the dead bodies of organisms may be well preserved in ice, in hardened resin of coniferous trees (amber), in tar, or in anaerobic, acidic peat. Fossilization can sometimes be a trace, an impression of a form. Examples include leaves and footprints, the fossils of which are made in layers that then harden. This article is about the skeletal organs. ... This article is about a type of online computer game. ... For other uses, see Mineral (disambiguation). ... Petrified wood In geology, petrifaction or petrification is the process by which organic material is converted into stone or a similar substance. ... For other uses, see Sand (disambiguation). ... This article is about precipitation. ... Flooding in Amphoe Sena, Ayutthaya Province, Thailand. ... This article is about water ice. ... This article does not cite any references or sources. ... Orders & Families Cordaitales † Pinales   Pinaceae - Pine family   Araucariaceae - Araucaria family   Podocarpaceae - Yellow-wood family   Sciadopityaceae - Umbrella-pine family   Cupressaceae - Cypress family   Cephalotaxaceae - Plum-yew family   Taxaceae - Yew family Vojnovskyales † Voltziales † “Conifer” redirects here. ... For other uses, see Amber (disambiguation). ... For other uses, see Acid (disambiguation). ... Peat in Lewis, Scotland Peat is an accumulation of partially decayed vegetation matter. ...


Fossil records

Fossil trilobite. Trilobites were hard-shelled arthropods, related to living horseshoe crabs and spiders, that first appeared in significant numbers around 540 mya, dying out 250 mya.

It is possible to find out how a particular group of organisms evolved by arranging its fossil records in a chronological sequence. Such a sequence can be determined because fossils are mainly found in sedimentary rock. Sedimentary rock is formed by layers of silt or mud on top of each other; thus, the resulting rock contains a series of horizontal layers, or strata. Each layer contains fossils which are typical for a specific time period during which they were made. The lowest strata contain the oldest rock and the earliest fossils, while the highest strata contain the youngest rock and more recent fossils. Download high resolution version (878x1041, 124 KB) Wikipedia does not have an article with this exact name. ... Download high resolution version (878x1041, 124 KB) Wikipedia does not have an article with this exact name. ... For the robot vacuum cleaner, see Electrolux Trilobite. ... Binomial name Linnaeus, 1758 The horseshoe crab, horsefoot, king crab, or sauce-pan (Limulus polyphemus, formerly known as Limulus cyclops, Xiphosura americana, Polyphemus occidentalis) is a chelicerate arthropod. ... For other uses, see Spider (disambiguation). ... For other uses of mya, see mya (disambiguation). ... For other uses, see Extinction (disambiguation). ... Two types of sedimentary rock: limey shale overlaid by limestone. ... For other uses, see Silt (disambiguation). ... For other uses, see strata (novel) and strata title. ... A geologic period is a subdivision of geologic time that divides an era into smaller timeframes. ...


A succession of animals and plants can also be seen from fossil records. By studying the number and complexity of different fossils at different stratigraphic levels, it has been shown that older fossil-bearing rocks contain fewer types of fossilized organisms, and they all have a simpler structure, whereas younger rocks contain a greater variety of fossils, often with increasingly complex structures. Succession is the act or process of pooing or of following in order or sequence. ... Stratigraphy, a branch of geology, studies rock layers and layering (stratification). ...


In the past, geologists could only roughly estimate the ages of various strata and the fossils found. They did so, for instance, by estimating the time for the formation of sedimentary rock layer by layer. Today, by measuring the proportions of radioactive and stable elements in a given rock, the ages of fossils can be more precisely dated by scientists. This technique is known as radiometric dating. Radioactive decay is the process in which an unstable atomic nucleus loses energy by emitting radiation in the form of particles or electromagnetic waves. ... The periodic table of the chemical elements A chemical element, or element, is a type of atom that is defined by its atomic number; that is, by the number of protons in its nucleus. ... Radiometric dating (often called radioactive dating) is a technique used to date materials, based on a comparison between the observed abundance of particular naturally occurring radioactive isotopes and their known decay rates. ...


Throughout the fossil record, many species that appear at an early stratigraphic level disappear at a later level. This is interpreted in evolutionary terms as indicating the times at which species originated and became extinct. Geographical regions and climatic conditions have varied throughout the Earth's history. Since organisms are adapted to particular environments, the constantly changing conditions favoured species which adapted to new environments through the mechanism of natural selection. Geological time put in a diagram called a geological clock, showing the relative lengths of the eons of the Earths history. ... For other uses, see Natural selection (disambiguation). ...


According to fossil records, some modern species of plants and animals are found to be almost identical to the species that lived in ancient geological ages. They are existing species of ancient lineages that have remained morphologically (and probably also physiologically) somewhat unchanged for a very long time. Consequently, they are called "living fossils" by laypeople. Examples of "living fossils" include the tuatara, the nautilus, the horseshoe crab, the coelacanth, the ginkgo, the Wollemi pine, and the metasequoia. The term morphology in biology refers to the outward appearance (shape, structure, colour, pattern) of an organism or taxon and its component parts. ... This article or section does not cite any references or sources. ... This article or section does not adequately cite its references or sources. ... For the experimental music band, see Tuatara (band). ... Genera Allonautilus Nautilus Nautilus (from Greek ναυτίλος, sailor) is the common name of any marine creatures of the cephalopod family Nautilidae, the sole family of the suborder Nautilina. ... Binomial name Linnaeus, 1758 The horseshoe crab, horsefoot, king crab, or sauce-pan (Limulus polyphemus, formerly known as Limulus cyclops, Xiphosura americana, Polyphemus occidentalis) is a chelicerate arthropod. ... Families See text. ... Species G. biloba L. The Ginkgo (Ginkgo biloba; 銀杏 in Chinese), frequently misspelled as Gingko, and also known as the Maidenhair Tree, is a unique tree with no close living relatives. ... Binomial name Wollemia nobilis The Wollemi Pine (Wollemia nobilis) is a remarkable coniferous tree that was discovered in 1994 in a remote series of narrow, steep-sided sandstone gorges in a mild temperate-zone rainforest wilderness area of the Wollemi National Park in New South Wales, 150 kilometers north-west... Binomial name Metasequoia glyptostroboides Hu & Cheng Metasequoia glyptostroboides (Dawn Redwood) is a fast growing tree in the conifer family Cupressaceae (Taxaceae or Taxodiaceae by others)native to the Sichuan-Hubei region of China. ...


Extent of the Fossil Record

Despite the relative rarity of suitable conditions for fossilization, approximately 250,000 fossil species are known[4]. The number of individual fossils this represents varies greatly from species to species, but many millions of fossils have been recovered: for instance, more than three million fossils from the last Ice Age have been recovered from the La Brea Tar Pits in Los Angeles[5]. Many more fossils are still in the ground, in various geological formations known to contain a high fossil density, allowing estimates of the total fossil content of the formation to be made. An example of this occurs in South Africa's Beaufort Formation (part of the Karoo Supergroup, which covers most of South Africa), which is rich in vertebrate fossils, including therapsids (reptile/mammal transitional forms)[6]. It has been estimated[7] that this formation contains 800 billion vertebrate fossils. Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ... La Brea Tar Pits in Los Angeles Countys Miracle Mile District. ... The Karoo Supergroup is the largest geological feature in Southern Africa, covering almost two thirds of the present land surface, including central Cape Province, almost all of Orange Free State, western Natal, much of south-east Transvaal, Zambia, Zimbabwe and Malawi. ... Groups Biarmosuchia Dinocephalia Anomodontia Theriodontia    Cynodontia       (...mammals) Therapsids, previously known as the mammal-like reptiles, are a group of synapsids. ... A transitional fossil or transitional form is the fossilized remains of a life form that illustrates an evolutionary transition. ...


Evolution of the horse

Evolution of the horse showing reconstruction of the fossil species obtained from successive rock strata. The foot diagrams are all front views of the left forefoot. The third metacarpal is shaded throughout. The teeth are shown in longitudinal section.

Due to an almost-complete fossil record found in North American sedimentary deposits from the early Eocene to the present, the horse provides one of the best examples of evolutionary history (phylogeny). Reconstruction, left forefoot skeleton (third digit emphasized yellow) and longitudinal section of molars of selected prehistoric horses The evolution of the horse involves the gradual development of the modern horse from the fox-sized, forest-dwelling Hyracotherium. ... Image File history File links Download high resolution version (1146x1392, 351 KB) Evolution of horse File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Download high resolution version (1146x1392, 351 KB) Evolution of horse File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Reconstruction, left forefoot skeleton (third digit emphasized yellow) and longitudinal section of molars of selected prehistoric horses The evolution of the horse involves the gradual development of the modern horse from the fox-sized, forest-dwelling Hyracotherium. ... The metacarpus is the intermediate part of the hand skeleton that is located between the fingers distally and the carpus which forms the connection to the forearm. ... North American redirects here. ... hfajhfiudshfas == == == --24. ... Binomial name Equus caballus Linnaeus, 1758 The horse (Equus caballus, sometimes seen as a subspecies of the Wild Horse, Equus ferus caballus) is a large odd-toed ungulate mammal, one of ten modern species of the genus Equus. ... In biology, phylogenetics (Greek: phylon = tribe, race and genetikos = relative to birth, from genesis = birth) is the study of evolutionary relatedness among various groups of organisms (e. ...


This evolutionary sequence starts with a small animal called the Hyracotherium which lived in North America about 54 million years ago, then spread across to Europe and Asia. Fossil remains of Hyracotherium show it to have differed from the modern horse in three important respects: it was a small animal (the size of a fox), lightly built and adapted for running; the limbs were short and slender, and the feet elongated so that the digits were almost vertical, with four digits in the forelimbs and three digits in the hindlimbs; and the incisors were small, the molars having low crowns with rounded cusps covered in enamel. This little horse lived 50 million years ago the person who discovered it called Mole Beast or Hyracotherium later they found another one but called it Dawn Horse the name was given to another Hyracotherium but it also goes by Eohippus. ... For other uses, see Europe (disambiguation). ... For other uses, see Asia (disambiguation). ... This article is about the animal. ... A forelimb is an anterior limb on an animals body. ... A hind limb is a posterior limb on an animal. ... Incisors (from Latin incidere, to cut) are the first kind of tooth in heterodont mammals. ... Molars are the rearmost and most complicated kind of tooth in most mammals. ... Cusp may refer to any of the following: In common parlance, a cusp is an important moment usually regarded as a decision point upon which consequent events are determined. ... Tooth enamel is the hardest and most highly mineralized substance of the body , and with dentin, cementum, and dental pulp is one of the four major parts of the tooth. ...


The probable course of development of horses from Hyracotherium to Equus (the modern horse) involved at least 12 genera and several hundred species. The major trends seen in the development of the horse to changing environmental conditions may be summarized as follows: For other uses, see Genus (disambiguation). ... For other uses, see Species (disambiguation). ...

  • Increase in size (from 0.4 m to 1.5 m);
  • Lengthening of limbs and feet;
  • Reduction of lateral digits;
  • Increase in length and thickness of the third digit;
  • Increase in width of incisors;
  • Replacement of premolars by molars; and
  • Increases in tooth length, crown height of molars.

Fossilized plants found in different strata show that the marshy, wooded country in which Hyracotherium lived became gradually drier. Survival now depended on the head being in an elevated position for gaining a good view of the surrounding countryside, and on a high turn of speed for escape from predators, hence the increase in size and the replacement of the splayed-out foot by the hoofed foot. The drier, harder ground would make the original splayed-out foot unnecessary for support. The changes in the teeth can be explained by assuming that the diet changed from soft vegetation to grass. A dominant genus from each geological period has been selected to show the progressive development of the horse. Incisors (from Latin incidere, to cut) are the first kind of tooth in heterodont mammals. ... The premolar teeth or bicuspids are transitional teeth located between the canine and molar teeth. ... Molars are the rearmost and most complicated kind of tooth in most mammals. ... This article is about marsh, a type of wetland. ... Predator and Prey redirect here. ... Vegetation is a general term for the plant life of a region; it refers to the ground cover provided by plants, and is, by far, the most abundant biotic element of the biosphere. ... For other uses, see Grass (disambiguation). ...


Limitations

The fossil record is an important source for scientists when tracing the evolutionary history of organisms. However, because of limitations inherent in the record, there are not fine scales of intermediate forms between related groups of species. This lack of continuous fossils in the record is a major limitation in tracing the descent of biological groups. Furthermore, there are also much larger gaps between major evolutionary lineages. These gaps are often referred to as "missing links". A transitional fossil or transitional form is the fossilized remains of a life form that illustrates an evolutionary transition. ...


There is a gap of about 100 million years between the early Cambrian period and the later Ordovician period. The early Cambrian period was the period from which numerous fossils of sponges, cnidarians (e.g., jellyfish), echinoderms (e.g., eocrinoids), molluscs (e.g., snails) and arthropods (e.g., trilobites) are found. In the later Ordovician period, the first animal that really possessed the typical features of vertebrates, the Australian fish, Arandaspis appeared. Thus few, if any, fossils of an intermediate type between invertebrates and vertebrates have been found, although likely candidates include the Burgess Shale animal, Pikaia gracilens, and its Maotianshan shales relatives, Myllokunmingia, Yunnanozoon, Haikouella lanceolata, and Haikouichthys. For other uses, see Cambrian (disambiguation). ... Artist impression of the Ordovician Sea. ... For other uses, see Sponge (disambiguation). ... Subphylum/Classes[1] Anthozoa — corals and sea anemones Medusozoa:[2] Cubozoa — sea wasps or box jellyfish Hydrozoa — hydroids, hydra-like animals Polypodiozoa Scyphozoa — jellyfish Staurozoa — stalked jellyfish unranked: Myxozoa - parasites Cnidaria[3] (IPA: [4]) is a phylum containing some 11,000 species of apparently simple animals found exclusively in aquatic... Bold text For other uses, see Jellyfish (disambiguation). ... Classes Subphylum Homalozoa Gill & Caster, 1960 Class Homostelea Class Homoiostelea Class Stylophora Gill & Caster, 1960 Class Ctenocystoidea Robison & Sprinkle, 1969 Subphylum Crinozoa Class Eocrinoidea Jaekel, 1899 Class Paracrinoidea Regnéll, 1945 Class Cystoidea von Buch, 1846 Class Blastoidea Class Crinoidea Subphylum Asterozoa Class Ophiuroidea Class Asteroidea Subphylum Echinozoa Helicoplacoidea †  ?Arkarua... Classes Caudofoveata Aplacophora Polyplacophora Monoplacophora Bivalvia Scaphopoda Gastropoda Cephalopoda † Rostroconchia † Helcionelloida † ?Bellerophontida The molluscs (British spelling) or mollusks (American spelling) are members of the very large and diverse phylum Mollusca. ... For other uses, see Snail (disambiguation). ... Subphyla and Classes Subphylum Trilobitomorpha Trilobita - trilobites (extinct) Subphylum Chelicerata Arachnida - spiders,scorpions, etc. ... For the robot vacuum cleaner, see Electrolux Trilobite. ... Typical classes Petromyzontidae (lampreys) Placodermi - extinct Chondrichthyes (cartilaginous fish) Acanthodii - extinct Actinopterygii (ray-finned fish) Actinistia (coelacanths) Dipnoi (lungfish) Amphibia (amphibians) Reptilia (reptiles) Aves (birds) Mammalia (mammals) Vertebrata is a subphylum of chordates, specifically, those with backbones or spinal columns. ... For other uses, see Fish (disambiguation). ... Arandaspis prionotolepis is an extinct species of jawless fish that lived in the Ordovician period, about 500 million years ago. ... Invertebrate is an English word that describes any animal without a spinal column. ... Hallucigenia sparsa, one of the organisms unique to the Burgess Shale. ... Pikaia gracilens is an extinct animal known from the Middle Cambrian fossil found near Mount Pika in the Burgess Shale of British Columbia. ... The Maotianshan shale is a lower Cambrian (Atdabanian) rock formation, of ca 522 Mya, now lying exposed in the Yunnan Province of China in the villages of Ercaicun and Chengjiang near the city of Kunming. ... The Myllokummingia is a primitive, probably agnathid (jawless) fish from the Lower Cambrian Maotianshan shales of China thought to be a vertebrate (see external links). ... The Yunnanozooan is a suspected chordate or hemichordate from the Lower Cambrian beds of Xiangchiang in Yunnan province, China. ... Binomial name Chen, Huang & Lii, Haikouella is a probable chordate from the Lower Cambrian Maotianshan shales of Chengjiang County in Yunnan Province, China. ... Binomial name Haikouichthys ercaicunensis was a primitive fish-like animal from the Early Cambrian Maotianshan shales of China. ...


Some of the reasons for the incompleteness of fossil records are:

  • In general, the probability that an organism becomes fossilized after death is very low;
  • Some species or groups are less likely to become fossils because they are soft-bodied;
  • Some species or groups are less likely to become fossils because they live (and die) in conditions that are not favourable for fossilization to occur in;
  • Many fossils have been destroyed through erosion and tectonic movements;
  • Some fossil remains are complete, but most are fragmentary;
  • Some evolutionary change occurs in populations at the limits of a species' ecological range, and as these populations are likely to be small, the probability of fossilization is lower (see punctuated equilibrium);
  • Similarly, when environmental conditions change, the population of a species is likely to be greatly reduced, such that any evolutionary change induced by these new conditions is less likely to be fossilized;
  • Most fossils convey information about external form, but little about how the organism functioned;
  • Using present-day biodiversity as a guide, this suggests that the fossils unearthed represent only a small fraction of the large number of species of organisms that lived in the past.

Punctuated equilibrium (or punctuated equilibria) is a theory in evolutionary biology which states that most sexually reproducing species will show little to no evolutionary change throughout their history. ... Rainforests are among the most biodiverse ecosystems on earth Biodiversity is the variation of taxonomic life forms within a given ecosystem, biome or for the entire Earth. ...

Evidence from comparative anatomy

Comparative study of the anatomy of groups of animals or plants reveals that certain structural features are basically similar. For example, the basic structure of all flowers consists of sepals, petals, stigma, style and ovary; yet the size, colour, number of parts and specific structure are different for each individual species. Comparative anatomy is the study of similarities and differences in the anatomy of organisms. ... For other uses, see Flower (disambiguation). ... Flower of the Primrose Willowherb (Ludwigia octovalvis) showing petals and sepals A sepal is one member or part of the calyx of a flower. ... It has been suggested that Corolla be merged into this article or section. ... A gynoecium(gyne: woman) is the female reproductive part of a flower, the male part of a flower is called androecium. ... Look up size in Wiktionary, the free dictionary. ... Color is an important part of the visual arts. ... For other uses, see Number (disambiguation). ...


Homologous structures and divergent (adaptive) evolution

If widely separated groups of organisms are originated from a common ancestry, they are expected to have certain basic features in common. The degree of resemblance between two organisms should indicate how closely related they are in evolution: Look up similarity in Wiktionary, the free dictionary. ...

  • Groups with little in common are assumed to have diverged from a common ancestor much earlier in geological history than groups which have a lot in common;
  • In deciding how closely related two animals are, a comparative anatomist looks for structures that are fundamentally similar, even though they may serve different functions in the adult. Such structures are described as homologous and suggest a common origin.
  • In cases where the similar structures serve different functions in adults, it may be necessary to trace their origin and embryonic development. A similar developmental origin suggests they are the same structure, and thus likely to be derived from a common ancestor.

When a group of organisms share a homologous structure which is specialized to perform a variety of functions in order to adapt different environmental conditions and modes of life are called adaptive radiation. The gradual spreading of organisms with adaptive radiation is known as divergent evolution. Missing link is a term for a transitional form from the fossil record that connects an earlier species to a later one, or which connects two different species to an earlier ancestor. ... This article does not cite any references or sources. ... For the adult insect stage, see Imago. ... In biology, homology is any similarity between structures that is due to their shared ancestry. ... Embryogenesis is the process by which the embryo is formed and develops. ... Four of the 13 finch species found on the Galápagos Archipelago, and thought to have evolved by an adaptive radiation that diversified their beak shapes to adapt them to different food sources. ... Divergent evolution occurs when two or more biological characteristics have a common evolutionary origin but have diverged over evolutionary time. ...


Pentadactyl limb

Figure 5a: The principle of homology illustrated by the adaptive radiation of the forelimb of mammals. All conform to the basic pentadactyl pattern but are modified for different usages. The third metacarpal is shaded throughout; the shoulder is crossed-hatched.

The pattern of limb bones called pentadactyl limb is an example of homologous structures (Fig. 5a). It is found in all classes of tetrapods (i.e. from amphibians to mammals). It can even be traced back to the fins of certain fossil fishes from which the first amphibians are thought to have evolved. The limb has a single proximal bone (humerus), two distal bones (radius and ulna), a series of carpals (wrist bones), followed by five series of metacarpals (palm bones) and phalanges (digits). Throughout the tetrapods, the fundamental structures of pentadactyl limbs are the same, indicating that they originated from a common ancestor. But in the course of evolution, these fundamental structures have been modified. They have become superficially different and unrelated structures to serve different functions in adaptation to different environments and modes of life. This phenomenon is clearly shown in the forelimbs of mammals. For example: Image File history File links Download high resolution version (2222x1578, 768 KB) Created by Jerry Crimson Mann 06:25, 2 August 2005 (UTC). ... Image File history File links Download high resolution version (2222x1578, 768 KB) Created by Jerry Crimson Mann 06:25, 2 August 2005 (UTC). ... In biology, homology is any similarity between structures that is due to their shared ancestry. ... In biology, dactyly is the arrangement of digits (fingers and toes) on the hands, feet, or sometimes wings of an animal. ... Groups See text. ... For other uses, see Amphibian (disambiguation). ... Subclasses & Infraclasses Subclass †Allotheria* Subclass Prototheria Subclass Theria Infraclass †Trituberculata Infraclass Metatheria Infraclass Eutheria Mammals (class Mammalia) are warm-blooded, vertebrate animals characterized by the presence of sweat glands, including milk producing sweat glands, and by the presence of: hair, three middle ear bones used in hearing, and a neocortex... A fin is a surface used to produce lift and thrust or to steer while traveling in water, air, or other fluid media. ... The humerus is a long bone in the arm or fore-legs (animals) that runs from the shoulder to the elbow. ... The radius is the bone of the forearm that extends from the outside of your limb to your phlangx (lateral) of the elbow to the thumb side of the wrist. ... The ulna (Elbow Bone) [Figs. ... In human anatomy, the carpal bones are the bones of the human wrist. ... For the municipality in Germany, see Wrist, Germany. ... For other uses, see Hand (disambiguation). ... The Kataeb Party, better known in English-speaking countries as the Phalange, is a Lebanese political party that was first established as a Maronite nationalist youth movement in 1936 by Pierre Gemayel. ...

  • In the monkey, the forelimbs are much elongated to form a grasping hand for climbing and swinging among trees.
  • In the pig, the first digit is lost, and the second and fifth digits are reduced. The remaining two digits are longer and stouter than the rest and bear a hoof for supporting the body.
  • In the horse, the forelimbs are adapted for support and running by great elongation of the third digit bearing a hoof.
  • The mole has a pair of short, spade-like forelimbs for burrowing.
  • The anteater uses its enlarged third digit for tearing down ant hills and termite nests.
  • In the whale, the forelimbs become flippers for steering and maintaining equilibrium during swimming.
  • In the bat, the forelimbs have turned into wings for flying by great elongation of four digits, while the hook-like first digit remains free for hanging from trees.

Approximate worldwide distribution of monkeys. ... For other uses, see Pig (disambiguation). ... For other uses, see Mole. ... A burrow is a hole or tunnel dug into the ground by an animal to create a space suitable for habitation, temporary refuge, or as a byproduct of locomotion. ... For other uses, see Anteater (disambiguation). ... For other uses, see Ant (disambiguation). ... Families Mastotermitidae Kalotermitidae Termopsidae Hodotermitidae Rhinotermitidae Serritermitidae Termitidae Termites, sometimes known as white ants, are a group of social insects usually classified at the taxonomic rank of order Isoptera. ... This article is about the animal. ... A flipper is a digitless, typically flat limb evolved for movement through water. ... “Chiroptera” redirects here. ... For other uses, see Wing (disambiguation). ... Look up Hook in Wiktionary, the free dictionary. ... The coniferous Coast Redwood, the tallest tree species on earth. ...

Insect mouthparts

Figure 5b: Adaptive radiation of insect mouthparts: a, antennae; c, compound eye; lb, labrium; lr, labrum; md, mandibles; mx, maxillae.

The basic structures are the same, including a labrum (upper lip), a pair of mandibles, a hypopharynx (floor of mouth), a pair of maxillae, and a labium. These structures are enlarged and modified; others are reduced and lost. The modifications enable the insects to exploit a variety of food materials (Fig. 5b): Image File history File links Download high resolution version (898x857, 240 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links Download high resolution version (898x857, 240 KB) File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Four of the 13 finch species found on the Galápagos Archipelago, and thought to have evolved by an adaptive radiation that diversified their beak shapes to adapt them to different food sources. ... Insects display a wide variety of antennal shapes. ... Compound eye of a dragonfly A compound eye is a visual organ found in arthropods such as insects and crustaceans. ... A labrum (Latin for lip) is the large vessel of a warm bath in the Roman thermae. ... The mandible (from Latin mandibŭla, jawbone) or inferior maxillary bone is, together with the maxilla, the largest and strongest bone of the face. ... In human anatomy, the hypopharynx is the bottom part of the pharynx, and is the part of the throat that connects to the esophagus. ... The maxillae are the largest bones of the face, except for the mandible, and form, by their union, the whole of the upper jaw. ...


(A) Primitive state — biting and chewing: e.g. grasshopper. Strong mandibles and maxillae for manipulating food. For other uses, see Grasshopper (disambiguation). ...


(B) Ticking and biting: e.g. honey bee. Labium long to lap up nectar; mandibles chew pollen and mould wax. The honeybee is a colonial insect that is often maintained, fed, and transported by farmers. ... In Greek mythology, nectar and ambrosia are the food of the gods. ... SEM image of pollen grains from a variety of common plants: sunflower (Helianthus annuus), morning glory (Ipomoea purpurea), prairie hollyhock (Sidalcea malviflora), oriental lily (Lilium auratum), evening primrose (Oenothera fruticosa), and castor bean (Ricinus communis). ... candle wax This page is about the substance. ...


(C) Sucking: e.g. butterfly. Labrum reduced; mandibles lost; maxillae long forming sucking tube. Superfamilies and families Superfamily Hedyloidea: Hedylidae Superfamily Hesperioidea: Hesperiidae Superfamily Papilionoidea: Papilionidae Pieridae Nymphalidae Lycaenidae Riodinidae A butterfly is an insect of the order Lepidoptera. ...


(D) Piercing and sucking, e.g. female mosquito. Labrum and maxillae form tube; mandibles form piercing stylets; labrum grooved to hold other parts. For other uses, see Mosquito (disambiguation). ...


Other arthropod appendages

Insect mouthparts and antennae are considered homologues of insect legs. Parallel developments are seen in some arachnids: The anterior pair of legs may be modified as analogues of antennae, particularly in whip scorpions, which walk on six legs. These developments provide support for the theory that complex modifications often arise by duplication of components, with the duplicates modified in different directions. Orders Acarina Amblypygi Araneae Opiliones Palpigradi Pseudoscorpionida Ricinulei Schizomida Scorpiones Solifugae Uropygi The arachnids, Arachnida, are a class of invertebrate animals in the subphylum Chelicerata. ... Families Geralinuridae Thelyphonidae A uropygid, commonly known as a Whip Scorpion, is an invertebrate animal belonging to the former order Uropygi in the class Arachnida, in the subphylum Chelicerata of the phylum Arthropoda. ...


Analogous structures and convergent evolution

See also: Evolution of the eye
Figure 6: Inverted retina of vertebrate (left) and non-inverted retina of octopus (right)

Under similar environmental conditions, fundamentally different structures in different groups of organisms may undergo modifications to serve similar functions. This phenomenon is called convergent evolution. Similar structures, physiological processes or mode of life in organisms apparently bearing no close phylogenetic links but showing adaptations to perform the same functions are described as analogous, for example: Diagram of major stages in the eyes evolution. ... Image File history File links Created by Jerry Crimson Mann 07:07, 2 August 2005 (UTC). ... Image File history File links Created by Jerry Crimson Mann 07:07, 2 August 2005 (UTC). ... In evolutionary biology, convergent evolution is the process whereby organisms not closely related, independently evolve similar traits as a result of having to adapt to similar environments or ecological niches. ... Analogy is both the cognitive process of transferring information from a particular subject (the analogue or source) to another particular subject (the target), and a linguistic expression corresponding to such a process. ...

  • Wings of bats, birds and insects;
  • the jointed legs of insects and vertebrates;
  • tail fin of fish, whale and lobster;
  • eyes of the vertebrates and cephalopod molluscs (squid and octopus). Fig. 6 illustrates difference between an inverted and non-inverted retina, the sensory cells lying beneath the nerve fibres. This results in the sensory cells being absent where the optic nerve is attached to the eye, thus creating a blind spot. The octopus eye has a non-inverted retina in which the sensory cells lie above the nerve fibres. There is therefore no blind spot in this kind of eye. Apart from this difference the two eyes are remarkably similar, an example of convergent evolution.

“Chiroptera” redirects here. ... For other uses, see Bird (disambiguation). ... Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera... Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera... This article does not cite any references or sources. ... A fin is a surface used to produce lift and thrust or to steer while traveling in water, air, or other fluid media. ... For other uses, see Fish (disambiguation). ... This article is about the animal. ... Subfamilies and Genera Neophoberinae Acanthacaris Thymopinae Nephropsis Nephropides Thymops Thymopsis Nephropinae Homarus Nephrops Homarinus Metanephrops Eunephrops Thymopides Clawed lobsters comprise a family (Nephropidae, sometimes also Homaridae) of large marine crustaceans. ... For other uses, see Eye (disambiguation). ... This article does not cite any references or sources. ... Orders Subclass Nautiloidea †Plectronocerida †Ellesmerocerida †Actinocerida †Pseudorthocerida †Endocerida †Tarphycerida †Oncocerida †Discosorida Nautilida †Orthocerida †Ascocerida †Bactritida Subclass †Ammonoidea †Goniatitida †Ceratitida †Ammonitida Subclass Coleoidea †Belemnoidea †Aulacocerida †Belemnitida †Hematitida †Phragmoteuthida Neocoleoidea (most living cephalopods) ?†Boletzkyida Sepiida Sepiolida Spirulida Teuthida Octopoda Vampyromorphida The cephalopods (Greek plural (kephalópoda); head-foot) are the mollusc class... For other uses, see Squid (disambiguation). ... For other uses, see Octopus (disambiguation). ... Human eye cross-sectional view. ... An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, which conducts electrical impulses away from the neurons cell body or soma. ... This article is about the anatomical structure. ... For other uses, see Blind spot. ...

Vestigial structures

Main article: Vestigiality

A further aspect of comparative anatomy is the presence of vestigial organs. Organs that are smaller and simpler in structure than corresponding parts in the ancestral species are called vestigial organs. They are usually degenerated or underdeveloped. The existence of vestigial organs can be explained in terms of changes in the environment or modes of life of the species. Those organs are thought to be functional in the ancestral species but have now become unnecessary and non-functional. Examples are the vestigial hind limbs of whales, the haltere (vestigial hind wings) of flies and mosquitos, vestigial wings of flightless birds such as ostriches, and the vestigial leaves of some xerophytes (e.g. cactus) and parasitic plants (e.g. dodder). It must be noted, however, that vestigial structures have lost the original function but may have another one. For example the halteres in dipterists help balance the insect while in flight and the wings of ostriches are used in mating rituals. The human vermiform appendix is a vestigial structure; it no longer retains its original function. ... Halteres, (singular halter or haltere) from the Greek word for dumbbells, are small knobbed structures homologous to wings and flapped to maintain stability when flying. ... For other uses, see Wing (disambiguation). ... For other uses, see Fly (disambiguation) and Flies (disambiguation). ... Binomial name Linnaeus, 1758 The present-day distribution of Ostriches. ... Look up foliage in Wiktionary, the free dictionary. ... A xerophyte describes a plant that has structural (xeromorphic) and physiological adaptations which enable them to survive, or even thrive, in areas with very little free moisture. ... Subfamilies Cactoideae Maihuenioideae Opuntioideae Pereskioideae See also taxonomy of the Cactaceae A cactus (plural cacti, cactuses or cactus) is any member of the succulent plant family Cactaceae, native to the Americas. ... About 4,100 species in approximately 19 families of flowering plants are either partly or completely parasitic on other plants [1]. Parasitic plants have a modified root, the haustorium, that penetrates the host plant and connects to the xylem or phloem or both. ... Species About 100 species, including: Cuscuta americana Cuscuta applanata Cuscuta approximata Cuscuta attenuata Cuscuta boldinghii Cuscuta brachycalyx Cuscuta californica Cuscuta campestris Cuscuta cassytoides Cuscuta ceanothi Cuscuta cephalanthi Cuscuta compacta Cuscuta coryli Cuscuta corylii Cuscuta cuspidata Cuscuta decipiens Cuscuta dentatasquamata Cuscuta denticulata Cuscuta epilinum Cuscuta epithymum Cuscuta erosa Cuscuta europaea Cuscuta... Halteres, (singular halter or haltere) from the Greek word for dumbbells, are small knobbed structures homologous to wings and flapped to maintain stability when flying. ... For other uses, see Fly (disambiguation) and Flies (disambiguation). ... Dates romantically sharing a chili cheese dog, in a dream sequence Courtship (sometimes called dating or going steady) is the process of selecting and attracting a mate for marriage. ...


Evidence from geographical distribution

Biologists have discovered many puzzling facts about the presence of certain species on various continents and islands (biogeography). Animated, colour-coded map showing the various continents. ... Biogeography is the science which deals with patterns of species distribution and the processes that result in such patterns. ...


Continental distribution

All organisms are adapted to their environment to a greater or lesser extent. If the abiotic and biotic factors within a habitat are capable of supporting a particular species in one geographic area, then one might assume that the same species would be found in a similar habitat in a similar geographic area, e.g. in Africa and South America. This is not the case. Plant and animal species are discontinuously distributed throughout the world: Habitat (which is Latin for it inhabits) is the place where a particular species live and grow. ... A world map showing the continent of Africa Africa is the worlds second-largest and second most-populous continent, after Asia. ... South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ...

Even greater differences can be found if Australia is taken into consideration though it occupies the same latitude as South America and Africa. Marsupials like the kangaroo can be found in Australia, but are totally absent from Africa and are only represented by the opossum in South America and the Virginia Opossum in North America: The Old World consists of those parts of Earth known to Europeans, Asians, and Africans before the voyages of Christopher Columbus; it includes Europe, Asia, and Africa (collectively known as Africa-Eurasia), plus surrounding islands. ... Genera and Species Loxodonta Loxodonta cyclotis Loxodonta africana Elephas Elephas maximus Elephas antiquus † Elephas beyeri † Elephas celebensis † Elephas cypriotes † Elephas ekorensis † Elephas falconeri † Elephas iolensis † Elephas planifrons † Elephas platycephalus † Elephas recki † Stegodon † Mammuthus † Elephantidae (the elephants) is a family of pachyderm, and the only remaining family in the order Proboscidea... For other uses, see Lion (disambiguation). ... Binomial name Linnaeus, 1758 Range map The giraffe (Giraffa camelopardalis) is an African even-toed ungulate mammal, the tallest of all land-living animal species. ... For other uses, see Cougar (disambiguation) or Puma (disambiguation). ... For other uses, see Jaguar (disambiguation). ... For other uses, see Llama (disambiguation). ... This article is about the geographical term. ... This article is about mammals. ... Species Macropus rufus Macropus giganteus Macropus fuliginosus Macropus antilopinus A kangaroo is a marsupial from the family Macropodidae (macropods, meaning large foot). In common use the term is used to describe the largest species from this family, the Red Kangaroo, the Antilopine Kangaroo, and the Eastern and Western Grey Kangaroo... Genera Several; see text Opossum fur is quite soft. ... South America South America is a continent crossed by the equator, with most of its area in the Southern Hemisphere. ... Binomial name (Kerr, 1792) The Virginia Opossum (Didelphis virginiana) is the only marsupial found in North America north of the Rio Grande River. ... North American redirects here. ...

  • The echidna and platypus, the only living representatives of primitive egg-laying mammals (monotremes), can be found only in Australia and are totally absent in the rest of the world.
  • On the other hand, Australia has very few placental mammals except those that have been introduced by human beings.

For other senses of this word, see echidna (disambiguation). ... For other uses, see Platypus (disambiguation). ... Families †Kollikodontidae Ornithorhynchidae Tachyglossidae †Steropodontidae Monotremes (monos, single + trema, hole; refers to the cloaca) are mammals that lay eggs instead of giving birth to live young like marsupials (Metatheria) and placental mammals (Eutheria). ... Orders[1] Bobolestes Eomaia Maelestes Montanalestes Murtoilestes Prokennalestes Placentalia Superorder Xenarthra: Cingulata (Armadillos) Pilosa (Sloths, True Anteaters) Superorder Afrotheria: Afrosoricida (Tenrecs, etc. ... IT is a new species. ...

Explanation

Figure 7: Diagrams to the land bridge between continents in past geological time (A) and the barriers formed (B) due to the submergence of land bridges.

The main groups of modern mammal arose in Northern Hemisphere and subsequently migrated to three major directions: Image File history File links Download high resolution version (1082x379, 100 KB) Created by Jerry Crimson Mann 10:07, 2 August 2005 (UTC). ... Image File history File links Download high resolution version (1082x379, 100 KB) Created by Jerry Crimson Mann 10:07, 2 August 2005 (UTC). ... This article or section does not cite its references or sources. ... Northern hemisphere highlighted in yellow. ...

  • to South America via the land bridge in the Bering Strait and Isthmus of Panama; A large number of families of South American marsupials became extinct as a result of competition with these North American counterparts.
  • to Africa via the Strait of Gibraltar; and
  • to Australia via South East Asia to which it was at one time connected by land

The shallowness of the Bering Strait would have made the passage of animals between two northern continents a relatively easy matter, and it explains the present-day similarity of the two faunas. But once they had got down into the southern continents, they presumably became isolated from each other by various types of barriers. This article or section does not cite its references or sources. ... Satellite photo of the Bering Strait Photo across the Bering Strait Nautical chart of the Bering Strait The Bering Strait (Russian: ) is a sea strait between Cape Dezhnev, Russia, the easternmost point (169°43 W) of the Asian continent and Cape Prince of Wales, Alaska, the westernmost point (168°05... The Isthmus of Panama. ... The Strait of Gibraltar as seen from space (on the left: Spain) A view across the Strait of Gibraltar taken from the hills over Tarifa, Spain The Strait of Gibraltar (Arabic: مضيق جبل طارق, Spanish: Estrecho de Gibraltar) is the strait that connects the Atlantic Ocean to the Mediterranean Sea and separates Spain... Fauna is a collective term for animal life. ...

  • The submerging of the Isthmus of Panama: isolates the South American fauna
  • the Mediterranean Sea and the North African desert: partially isolate the African fauna; and
  • the submerging of the original connection between Australia and South East Asia: isolates the Australian fauna

Once isolated, the animals in each continent have shown adaptive radiation (Fig. 7) to evolve along their own lines. Mediterranean redirects here. ...


Evidence for migration and isolation

Map of the world showing distribution of present members of camel. Solid black lines indicate possible migration routes.

The fossil record for the camel indicated that evolution of camels started in North America, from which they migrated across the Bering Strait into Asia and hence to Africa, and through the Isthmus of Panama into South America. Once isolated, they evolved along their own lines, giving the modern camel in Asia and Africa and llama in South America. Image File history File links Created by Jerry Crimson Mann 10:57, 2 August 2005 (UTC). ... Image File history File links Created by Jerry Crimson Mann 10:57, 2 August 2005 (UTC). ... For other uses, see Camel (disambiguation). ...


Continental drift

The same kinds of fossils are found from areas known to be adjacent to one another in the past but which, through the process of continental drift, are now in widely divergent geographic locations. For example, fossils of the same types of ancient amphibians, arthropods and ferns are found in South America, Africa, India, Australia and Antarctica, which can be dated to the Paleozoic Era, at which time these regions were united as a single landmass called Gondwana. [8] Sometimes the descendants of these organisms can be identified and show unmistakable similarity to each other, even though they now inhabit very different regions and climates. Plates in the crust of the earth, according to the plate tectonics theory Continental drift refers to the movement of the Earths continents relative to each other. ... The Paleozoic Era (from the Greek palaio, old and zoion, animals, meaning ancient life) is the earliest of three geologic eras of the Phanerozoic eon. ... For other uses of Gondwana and Gondwanaland, see Gondwana (disambiguation). ...


Oceanic island distribution

Most small isolated islands only have native species that could have arrived by air or water; like birds, insects and turtles. The few large mammals present today were brought by human settlers in boats. Plant life on remote and recent volcanic islands like Hawaii could have arrived as airborne spores or as seeds in the droppings of birds. After the explosion of Krakatoa a century ago and the emergence of a steaming, lifeless remnant island called Anak Krakatoa (child of Krakatoa), plants arrived within months and within a year there were moths and spiders that had arrived by air. The island is now ecologially hard to distinguish from those around it that have been there for millions of years. For the 1969 film about the Krakatoa eruption, see Krakatoa, East of Java. ...


Evidence from comparative physiology and biochemistry

See also: Archaeogenetics, Common descent, Last universal ancestor, Most recent common ancestor, Nothing in Biology Makes Sense Except in the Light of Evolution, Speciation, Timeline of evolution, Timeline of human evolution, and Universal Code (Biology)

Archaeogenetics, a term coined by Colin Renfrew, refers to the application of the techniques of molecular population genetics to the study of the human past. ... A group of organisms is said to have common descent if they have a common ancestor. ... Last universal ancestor (LUA), the hypothetical latest living organism from which all currently living organisms descend. ... The most recent common ancestor (MRCA) of any set of organisms is the most recent individual from which all organisms in the group are directly descended. ... Nothing in Biology Makes Sense Except in the Light of Evolution is a 1973 essay by the evolutionary biologist and Russian Orthodox Christian Theodosius Dobzhansky, criticising Young Earth creationism and espousing evolutionary creationism. ... Charles Darwins first sketch of an evolutionary tree from his First Notebook on Transmutation of Species (1837) Speciation is the evolutionary process by which new biological species arise. ... Life on Earth  â€¢  â€¢  | Axis scale: millions of years ago. ... This article does not cite any references or sources. ... In biology, universal code is short for the idea of the universal genetic code. In all known living creatures, instructions for making proteins are encoded in DNA. Three bases of DNA (the codon) select an amino acid. ...

Universal biochemical organisation

All known extant organisms are based on the same fundamental biochemical organisation: genetic information encoded as nucleic acid (DNA, or RNA for viruses), transcribed into RNA, then translated into proteins (that is, polymers of amino acids) by highly conserved ribosomes. Perhaps most tellingly, the Genetic Code (the "translation table" between DNA and amino acids) is the same for almost every organism, meaning that a piece of DNA in a bacterium codes for the same amino acid as in a human cell. ATP is used as energy currency by all extant life. The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... For other uses, see RNA (disambiguation). ... For other uses, see RNA (disambiguation). ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... In chemistry, an amino acid is any molecule that contains both amino and carboxylic acid functional groups. ... Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ... For a non-technical introduction to the topic, see Introduction to Genetics. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Drawing of the structure of cork as it appeared under the microscope to Robert Hooke from Micrographia which is the origin of the word cell being used to describe the smallest unit of a living organism Cells in culture, stained for keratin (red) and DNA (green) The cell is the... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ...


Molecular variance patterns

A classic example of biochemical evidence for evolution is the variance of the protein Cytochrome c in living cells. The variance of cytochrome c of different organisms is measured in the number of differing amino acids, each differing amino acid being a result of a base pair substitution, a mutation. If each differing amino acid is assumed to be the result of one base pair substitution, it can be calculated how long ago the two species diverged by multiplying the number of base pair substitutions by the estimated time it takes for a substituted base pair of the cytochrome c gene to be successfully passed on. For example, if the average time it takes for a base pair of the cytochrome c gene to mutate is N years, the number of amino acids making up the cytochrome c protein in monkeys differ by one from that of humans, this leads to the conclusion that the two species diverged N years ago. A representation of the 3D structure of myoglobin showing coloured alpha helices. ... Cytochrome c with heme c. ... Base pairs, of a DNA molecule. ... For linguistic mutation, see Apophony. ...


Comparison of the DNA sequences allows organisms to be grouped by sequence similarity, and the resulting phylogenetic trees are typically congruent with traditional taxonomy, and are often used to strengthen or correct taxonomic classifications. Sequence comparison is considered a measure robust enough to be used to correct erroneous assumptions in the phylogenetic tree in instances where other evidence is scarce. For example, neutral human DNA sequences are approximately 1.2% divergent (based on substitutions) from those of their nearest genetic relative, the chimpanzee, 1.6% from gorillas, and 6.6% from baboons.[1] Genetic sequence evidence thus allows inference and quantification of genetic relatedness between humans and other apes.[2][3] The sequence of the 16S ribosomal RNA gene, a vital gene encoding a part of the ribosome, was used to find the broad phylogenetic relationships between all extant life. The analysis, originally done by Carl Woese, resulted in the three-domain system, arguing for two major splits in the early evolution of life. The first split led to modern Bacteria and the subsequent split led to modern Archaea and Eukaryote. Phylogenetic groups, or taxa, can be monophyletic, paraphyletic, or polyphyletic. ... For the science of classifying living things, see alpha taxonomy. ... Type species Simia troglodytes Blumenbach, 1775 distribution of Species Pan troglodytes Pan paniscus Chimpanzee, often shortened to chimp, is the common name for the two extant species of apes in the genus Pan. ... Type species Troglodytes gorilla Savage, 1847 distribution of Gorilla Species Gorilla gorilla Gorilla beringei The gorilla, the largest of the living primates, is a ground-dwelling omnivore that inhabits the forests of Africa. ... For other uses, see Baboon (disambiguation). ... This article is about the biological superfamily. ... Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ... Carl Richard Woese (born July 15, 1928, Syracuse, New York) is an American microbiologist famous for defining the Archaea (a new domain or kingdom of life) in 1977 by phylogenetic taxonomy of 16S ribosomal RNA, a technique pioneered by Woese and which is now standard practice. ... The three-domain system is a biological classification introduced by Carl Woese in 1990 that emphasizes his separation of prokaryotes into two groups, originally called Eubacteria and Archaebacteria. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... Phyla Crenarchaeota Euryarchaeota Korarchaeota Nanoarchaeota ARMAN The Archaea (pronounced ) are a group of prokaryotic and single-celled microorganisms. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ...


The proteomic evidence also supports the universal ancestry of life. Vital proteins, such as the ribosome, DNA polymerase, and RNA polymerase, are found in everything from the most primitive bacteria to the most complex mammals. The core part of the protein is conserved across all lineages of life, serving similar functions. Higher organisms have evolved additional protein subunits, largely affecting the regulation and protein-protein interaction of the core. Other overarching similarities between all lineages of extant organisms, such as DNA, RNA, amino acids, and the lipid bilayer, give support to the theory of common descent. The chirality of DNA, RNA, and amino acids is conserved across all known life. As there is no functional advantage to right- or left-handed molecular chirality, the simplest hypothesis is that the choice was made randomly by early organisms and passed on to all extant life through common descent. Further evidence for reconstructing ancestral lineages comes from junk DNA such as pseudogenes, "dead" genes which steadily accumulate mutations.[4] The term proteome was coined by Mark Wilkins in 1995 (1) and is used to describe the entire complement of proteins in a given biological organism or system at a given time, i. ... A representation of the 3D structure of myoglobin showing coloured alpha helices. ... Figure 1: Ribosome structure indicating small subunit (A) and large subunit (B). ... 3D structure of the DNA-binding helix-hairpin-helix motifs in human DNA polymerase beta A DNA polymerase is an enzyme that assists in DNA replication. ... This article does not cite any references or sources. ... In structural biology, a protein subunit or subunit protein is a double protein molecule that assembles (or coassembles) with other protein molecules to form a multimeric or oligomeric protein. ... Protein-protein interactions refer to the association of protein molecules and the study of these associations from the perspective of biochemistry, signal transduction and networks. ... The structure of part of a DNA double helix Deoxyribonucleic acid, or DNA, is a nucleic acid molecule that contains the genetic instructions used in the development and functioning of all known living organisms. ... For other uses, see RNA (disambiguation). ... This fluid lipid bilayer cross section is made up entirely of phosphatidylcholine. ... The term chiral (pronounced ) is used to describe an object which is non-superimposable on its mirror image. ... In molecular biology, junk DNA is a collective label for the portions of the DNA sequence of a chromosome or a genome for which no function has yet been identified. ... A pseudogene is a nucleotide sequences that is similar to a normal gene, but is not expressed as a functional protein. ...


There is also a large body of molecular evidence for a number of different mechanisms for large evolutionary changes, among them: genome and gene duplication, which facilitates rapid evolution by providing substantial quantities of genetic material under weak or no selective constraints; horizontal gene transfer, the process of transferring genetic material to another cell that is not an organism's offspring, allowing for species to acquire beneficial genes from each other; and recombination, capable of reassorting large numbers of different alleles and of establishing reproductive isolation. The Endosymbiotic theory explains the origin of mitochondria and plastids (e.g. chloroplasts), which are organelles of eukaryotic cells, as the incorporation of an ancient prokaryotic cell into ancient eukaryotic cell. Rather than evolving eukaryotic organelles slowly, this theory offers a mechanism for a sudden evolutionary leap by incorporating the genetic material and biochemical composition of a separate species. Evidence supporting this mechanism has recently been found in the protist Hatena: as a predator it engufes a green algae cell, which subsequently behaves as an endosymbiont, nourishing Hatena, which in turn loses its feeding apparatus and behaves as an autotroph.[5][6] In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... Schematic of a region of a chromosome before and after a duplication event Gene duplication occurs when an error in homologous recombination, a retrotransposition event, or duplication of an entire chromosome leads to the duplication of a region of DNA containing a gene [1]. The significance of this process for... Horizontal gene transfer (HGT), also Lateral gene transfer (LGT), is any process in which an organism transfers genetic material to another cell that is not its offspring. ... Genetic recombination is the process by which a strand of the genetic material (usually DNA; but can also be RNA) is broken and then joined to the end of a different DNA molecule. ... For the hard rock band, see Allele (band). ... An important concept in evolutionary biology, reproductive isolation is a category of mechanisms that prevent two or more populations from exchanging genes. ... The endosymbiotic theory concerns the origins of mitochondria and plastids (e. ... Electron micrograph of a mitochondrion showing its mitochondrial matrix and membranes In cell biology, a mitochondrion (plural mitochondria) is a membrane-enclosed organelle that is found in most eukaryotic cells. ... Plastids are a class of membrane-bound organelles found in plant and algal cells. ... Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. ... Schematic of typical animal cell, showing subcellular components. ... Prokaryotic bacteria cell structure Prokaryotes (IPA: //) are a group of organisms that lack a cell nucleus (= karyon), or any other membrane-bound organelles. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... Kingdoms Animalia - Animals Fungi Plantae - Plants Chromalveolata Protista Alternative phylogeny Unikonta Opisthokonta Metazoa Choanozoa Eumycota Amoebozoa Bikonta Apusozoa Cabozoa Rhizaria Excavata Corticata Archaeplastida Chromalveolata Animals, plants, fungi, and protists are eukaryotes (IPA: ), organisms whose cells are organized into complex structures by internal membranes and a cytoskeleton. ... Schematic of typical animal cell, showing subcellular components. ... Typical phyla Chromalveolata Chromista Heterokontophyta Haptophyta Cryptophyta (cryptomonads) Alveolata Dinoflagellata Apicomplexa Ciliophora (ciliates) Cabozoa Excavata Euglenozoa Percolozoa Metamonada Rhizaria Radiolaria Foraminifera Cercozoa Archaeplastida (in part) Rhodophyta (red algae) Glaucophyta (basal archaeplastids) Amoebozoa Choanozoa Many others; classification varies Protists (IPA: (RP); (GenAm)), Greek protiston -a meaning the (most) first of all... Hatena (or mysterious) is a new creature discovered in Japan. ... Divisions Chlorophyta Charophyta Green algae are microscopic protists; found in all aquatic environments, including marine, freshwater and brackish water. ... An endosymbiont is any organism that lives within the body or cells of another organism, i. ... Green (from chlorophyll) fronds of a maidenhair fern: a photoautotroph Flowchart to determine if a species is autotroph, heterotroph, or a subtype An autotroph (from the Greek autos = self and trophe = nutrition) is an organism that produces complex organic compounds from simple inorganic molecules and an external source of energy...


Since metabolic processes do not leave fossils, research into the evolution of the basic cellular processes is done largely by comparison of existing organisms. Many lineages diverged when new metabolic processes appeared, and it is theoretically possible to determine when certain metabolic processes appeared by comparing the traits of the descendants of a common ancestor or by detecting their physical manifestations. As an example, the appearance of oxygen in the earth's atmosphere is linked to the evolution of photosynthesis. Structure of the coenzyme adenosine triphosphate, a central intermediate in energy metabolism. ... This article is about the chemical element and its most stable form, or dioxygen. ... Air redirects here. ... assimilation. ...


Out of Africa hypothesis of human evolution

Main article: Recent single-origin hypothesis

Mathematical models of evolution, pioneered by the likes of Sewall Wright, Ronald Fisher and J. B. S. Haldane and extended via diffusion theory by Motoo Kimura, allow predictions about the genetic structure of evolving populations. Direct examination of the genetic structure of modern populations via DNA sequencing has recently allowed verification of many of these predictions. For example, the Out of Africa theory of human origins, which states that modern humans developed in Africa and a small sub-population migrated out (undergoing a population bottleneck), implies that modern populations should show the signatures of this migration pattern. Specifically, post-bottleneck populations (Europeans and Asians) should show lower overall genetic diversity and a more uniform distribution of allele frequencies compared to the African population. Both of these predictions are borne out by actual data from a number of studies.[citation needed] Map of early human migrations according to mitochondrial population genetics In paleoanthropology, the recent single-origin hypothesis (RSOH, or Out-of-Africa model, or Replacement Hypothesis) is one of two accounts of the origin of anatomically modern humans, Homo sapiens. ... Sewall Green Wright ForMemRS (December 21, 1889 – March 3, 1988) was an American geneticist known for his influential work on evolutionary theory. ... Sir Ronald Aylmer Fisher, FRS (17 February 1890 – 29 July 1962) was an English statistician, evolutionary biologist, and geneticist. ... John Burdon Sanderson Haldane (November 5, 1892 – December 1, 1964), who normally used J.B.S. as a first name, was a British geneticist and evolutionary biologist. ... The heat equation or diffusion equation is an important partial differential equation which describes the variation of temperature in a given region over time. ... Motoo Kimura (木村資生, born on November 13, 1924 in Okazaki, Aichi Prefecture - November 13, 1994) was a highly influential Japanese mathematical biologist, working in the field of theoretical population genetics. ... Map of early human migrations according to mitochondrial population genetics In paleoanthropology, the recent single-origin hypothesis (RSOH, or Out-of-Africa model, or Replacement Hypothesis) is one of two accounts of the origin of anatomically modern humans, Homo sapiens. ... A population bottleneck (or genetic bottleneck) is an evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented from reproducing, and the population is reduced by 50% or more, often by several orders of magnitude. ...


Evidence from antibiotic and pesticide resistance

The development and spread of antibiotic resistant bacteria, like the spread of pesticide resistant forms of plants and insects is evidence for evolution of species, and of change within species. Thus the appearance of vancomycin resistant Staphylococcus aureus, and the danger it poses to hospital patients is a direct result of evolution through natural selection. The rise of Shigella strains resistant to the synthetic antibiotic class of sulfonamides also demonstrates the generation of new information as an evolutionary process[7]. Similarly, the appearance of DDT resistance in various forms of Anopheles mosquitoes, and the appearance of myxomatosis resistance in breeding rabbit populations in Australia, are all evidence of the existence of evolution in situations of evolutionary selection pressure in species in which generations occur rapidly. Antibiotic resistance is the ability of a microorganism to withstand the effects of an antibiotic. ... Phyla Actinobacteria Aquificae Chlamydiae Bacteroidetes/Chlorobi Chloroflexi Chrysiogenetes Cyanobacteria Deferribacteres Deinococcus-Thermus Dictyoglomi Fibrobacteres/Acidobacteria Firmicutes Fusobacteria Gemmatimonadetes Lentisphaerae Nitrospirae Planctomycetes Proteobacteria Spirochaetes Thermodesulfobacteria Thermomicrobia Thermotogae Verrucomicrobia Bacteria (singular: bacterium) are unicellular microorganisms. ... A cropduster spreading pesticide. ... Crystal structure of a short peptide L-Lys-D-Ala-D-Ala (bacterial cell wall precursor, in green) bound to vancomycin (blue) through hydrogen bonds. ... Binomial name Staphylococcus aureus Staphylococcus aureus (also known as golden staph) is a bacterium, frequently living on the skin or in the nose of a healthy person, that can cause illnesses ranging from minor skin infections (such as pimples, boils, and cellulitis) and abscesses, to life-threatening diseases such as... Species S. boydii S. dysenteriae S. flexneri S. sonnei This article is about the bacteria. ... Sulfonamides, also known as sulfa drugs, are synthetic antimicrobial agents derived from sulfonic acid. ... For other uses: see DDT (disambiguation). ... Some Species Anopheles atroparvus Anopheles barberi Anopheles beklemishevi Anopheles coustani Anopheles crypticus Anopheles culicifacies Anopheles earlei Anopheles farauti Anopheles fluviatilis Anopheles forattinii Anopheles funestus Anopheles gambiae Anopheles grabhamii Anopheles hailarensis Anopheles halophylus Anopheles hyrcanus Anopheles introlatus Anopheles kosiensis Anopheles latens Anopheles maculipennis Anopheles minimus Anopheles moucheti Anopheles nili Anopheles ovengensis... A European Rabbit afflicted by Myxomatosis in Shropshire, England. ... Evolutionary pressure or selection pressure can be formalized as an external pressure applied to a process, thereby pushing that process in a distinct direction. ...


Evidence from studies of complex iteration

"It has taken more than five decades, but the electronic computer is now powerful enough to simulate evolution" [9] assisting bioinformatics in its attempt to solve biological problems. Map of the human X chromosome (from the NCBI website). ...


Computer science allows the iteration of self changing complex systems to be studied, allowing a mathematical understanding of the nature of the processes behind evolution; providing evidence for the hidden causes of known evolutionary events. The evolution of specific cellular mechanisms like spliceosomes that can turn the cell's genome into a vast workshop of billions of interchangeable parts that can create tools that create tools that create tools that create us can be studied for the first time in an exact way. Computer science, or computing science, is the study of the theoretical foundations of information and computation and their implementation and application in computer systems. ... The word iteration is sometimes used in everyday English with a meaning virtually identical to repetition. ... There are many definitions of complexity, therefore many natural, artificial and abstract objects or networks can be considered to be complex systems, and their study (complexity science) is highly interdisciplinary. ... A spliceosome is a complex of RNA and many protein subunits called snRNPs, that removes the non-coding introns from unprocessed mRNA. Spliceosomes are unique to eukaryotic mRNA as the mRNA of prokaryotes lack introns. ...


For example, Christoph Adami et al. make this point in Evolution of biological complexity:

To make a case for or against a trend in the evolution of complexity in biological evolution, complexity needs to be both rigorously defined and measurable. A recent information-theoretic (but intuitively evident) definition identifies genomic complexity with the amount of information a sequence stores about its environment. We investigate the evolution of genomic complexity in populations of digital organisms and monitor in detail the evolutionary transitions that increase complexity. We show that, because natural selection forces genomes to behave as a natural "Maxwell Demon," within a fixed environment, genomic complexity is forced to increase. [10]

For example, David J. Earl and Michael W. Deem make this point in Evolvability is a selectable trait: Maxwells demon is an 1867 thought experiment by the Scottish physicist James Clerk Maxwell, meant to raise questions about the possibility of violating the second law of thermodynamics. ...

Not only has life evolved, but life has evolved to evolve. That is, correlations within protein structure have evolved, and mechanisms to manipulate these correlations have evolved in tandem. The rates at which the various events within the hierarchy of evolutionary moves occur are not random or arbitrary but are selected by Darwinian evolution. Sensibly, rapid or extreme environmental change leads to selection for greater evolvability. This selection is not forbidden by causality and is strongest on the largest-scale moves within the mutational hierarchy. Many observations within evolutionary biology, heretofore considered evolutionary happenstance or accidents, are explained by selection for evolvability. For example, the vertebrate immune system shows that the variable environment of antigens has provided selective pressure for the use of adaptable codons and low-fidelity polymerases during somatic hypermutation. A similar driving force for biased codon usage as a result of productively high mutation rates is observed in the hemagglutinin protein of influenza A. [11]

"Computer simulations of the evolution of linear sequences have demonstrated the importance of recombination of blocks of sequence rather than point mutagenesis alone. Repeated cycles of point mutagenesis, recombination, and selection should allow in vitro molecular evolution of complex sequences, such as proteins." [12] Evolutionary molecular engineering, also called directed evolution or in vitro molecular evolution involves the iterated cycle of mutation, multiplication with recombination, and selection of the fittest of individual molecules (proteins, DNA, and RNA). Natural evolution can be relived showing us possible paths from catalytic cycles based on proteins to based on RNA to based on DNA. [13] [14] [15] [16] This article needs to be cleaned up to conform to a higher standard of quality. ... Genera Influenzavirus A Influenzavirus B Influenzavirus C Isavirus Thogotovirus Influenzavirus A is a genus of the Orthomyxoviridae family of viruses. ...


Evidence from speciation

Hawthorn fly

One example of evolution at work is the case of the hawthorn fly, Rhagoletis pomonella, also known as the apple maggot fly, which appears to be undergoing sympatric speciation.[8] Different populations of hawthorn fly feed on different fruits. A distinct population emerged in North America in the 19th century some time after apples, a non-native species, were introduced. This apple-feeding population normally feeds only on apples and not on the historically preferred fruit of hawthorns. The current hawthorn feeding population does not normally feed on apples. Some evidence, such as the fact that six out of thirteen allozyme loci are different, that hawthorn flies mature later in the season and take longer to mature than apple flies; and that there is little evidence of interbreeding (researchers have documented a 4-6% hybridization rate) suggests that this is occurring. The emergence of the new hawthorn fly is an example of evolution in progress.[9] Binomial name Rhagoletis pomonella Walsh, 1867 The Apple Maggot (Rhagoletis pomonella), also known as railroad worm, is a pest of several fruits, mainly apples. ... Comparison of allopatric, peripatric, parapatric and sympatric speciation. ... For other uses, see Apple (disambiguation). ... Species See text Crataegus (Hawthorn) is a large genus of in the family Rosaceae, native to temperate regions of the Northern Hemisphere in Europe, Asia and North America. ... In biochemistry, isozymes (or isoenzymes) are isoforms (closely related variants) of enzymes. ...


See also

History is often used as a generic term for information about the past, such as in geologic history of the Earth. When used as the name of a field of study, history refers to the study and interpretation of the record of human societies. ... There have been numerous objections to evolution since alternative evolutionary ideas came to be hotly debated around the start of the nineteenth century. ...

References

  1. ^ Two sources: 'Genomic divergences between humans and other hominoids and the effective population size of the common ancestor of humans and chimpanzees'. and 'Quantitative Estimates of Sequence Divergence for Comparative Analyses of Mammalian Genomes' "[1] [2]"
  2. ^ The picture labeled "Human Chromosome 2 and its analogs in the apes" in the article Comparison of the Human and Great Ape Chromosomes as Evidence for Common Ancestry is literally a picture of a link in humans that links two separate chromosomes in the nonhuman apes creating a single chromosome in humans. It is considered a missing link, and the ape-human connection is of particular interest. Also, while the term originally referred to fossil evidence, this too is a trace from the past corresponding to some living beings which when alive were the physical embodiment of this link.
  3. ^ The New York Times report Still Evolving, Human Genes Tell New Story, based on A Map of Recent Positive Selection in the Human Genome, states the International HapMap Project is "providing the strongest evidence yet that humans are still evolving" and details some of that evidence.
  4. ^ Pseudogene evolution and natural selection for a compact genome. "[3]"
  5. ^ Okamoto N, Inouye I. (2005). "A secondary symbiosis in progress". Science 310 (5746): 287. 
  6. ^ Okamoto N; Inouye I. (October 2006). "Hatena arenicola gen. et sp. nov., a Katablepharid Undergoing Probable Plastid Acquisition.". Protist 157 (4): 401-419. 
  7. ^ Tanaka T, Hashimoto H. (1989). "Drug-resistance and its transferability of Shigella strains isolated in 1986 in Japan". Kansenshogaku Zasshi 63 (1): 15-26. 
  8. ^ Feder et al (2003). "Evidence for inversion polymorphism related to sympatric host race formation in the apple maggot fly, Rhagoletis pomonella.". Genetics 163 (3): 939-953. 
  9. ^ Berlocher, S.H. and G.L. Bush. 1982. An electrophoretic analysis of Rhagoletis (Diptera: Tephritidae) phylogeny. Systematic Zoology 31:136-155; Berlocher, S.H. and J.L. Feder. 2002. Sympatric speciation in phytophagous insects: moving beyond controversy? Annual Review of Entomology 47:773-815; Bush, G.L. 1969. Sympatric host race formation and speciation in frugivorous flies of the genus Rhagoletis (Diptera: Tephritidae). Evolution 23:237-251; Prokopy, R.J., S.R. Diehl and S.S. Cooley. 1988. Behavioral evidence for host races in Rhagoletis pomonella flies. Oecologia 76:138-147. Proc. Natl. Acad. Sci. USA - Vol. 94, pp. 11417-11421, October 1997 - Evolution article Selective maintenance of allozyme differences among sympatric host races of the apple maggot fly.
  • Darwin, Charles November 24, 1859. On the Origin of Species by means of Natural Selection or the Preservation of Favoured Races in the Struggle for Life. London: John Murray, Albemarle Street. 502 pages. Reprinted: Gramercy (May 22, 1995). ISBN 0-517-12320-7
  • Mayr, Ernst. What Evolution Is. Basic Books (October, 2002). ISBN 0-465-04426-3
  • Gigerenzer, Gerd, et al., The empire of chance: how probability changed science and everyday life (New York: Cambridge University Press, 1989).
  • Williams, G.C. (1966). Adaptation and Natural Selection: A Critique of some Current Evolutionary Thought. Princeton, N.J.: Princeton University Press.
  • Biological science, Oxford, 2002.
  • CJ Clegg, 1999, Genetics and Evolution, John Murray. ISBN 0-7195-7552-4
  • Y.K. Ho, 2004, Advanced-level Biology for Hong Kong, Manhattan Press. ISBN 962-990-635-X
  • Paul, Christopher R. C. (1998) The Adequacy of the Fossil Record, John Wiley & Sons, ISBN 0-471-96988-5
  • Behrensmeyer, Anna K. (1980) Fossils in the making: Vertebrate taphonomy and paleoecology, University of Chicago Press, ISBN 0-226-04169-7
  • Martin, Ronald E. et al. eds. (1999) Taphonomy: A Process Approach, Cambridge University Press, ISBN 0-521-59833-8

The New York Times is an internationally known daily newspaper published in New York City and distributed in the United States and many other nations worldwide. ... The goal of the International HapMap Project is to develop a haplotype map of the human genome, also referred to as the HapMap, which will describe the common patterns of human genetic variation. ... Oecologia is an international peer-reviewed English language journal that publishes original research into topics related to ecology. ... is the 328th day of the year (329th in leap years) in the Gregorian calendar. ... Year 1859 (MDCCCLIX) was a common year starting on Saturday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Thursday of the 12-day slower Julian calendar). ... The 1859 edition of On the Origin of Species First published in 1859, The Origin of Species (full title On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life) by British naturalist Charles Darwin is one of the pivotal... John Murray is a British publishing house, renowned for the roster of authors it has published in its history, including Jane Austen, Lord Byron and Charles Darwin. ... View of Clarendon House, now demolished. ...

External links

PBS redirects here. ... While on board HMS Beagle, Charles Darwin collected numerous specimens, many new to science, which supported his later theory of evolution by natural selection. ... For other uses, see Adaptation (disambiguation). ... Macroevolution refers to evolution that occurs at or above the level of species, in contrast with microevolution, which refers to smaller evolutionary changes (typically described as changes in allele frequencies) within a species or population. ... Microevolution is the occurrence of small-scale changes in allele frequencies in a population, over a few generations, also known as change at or below the species level. ... Charles Darwins first sketch of an evolutionary tree from his First Notebook on Transmutation of Species (1837) Speciation is the evolutionary process by which new biological species arise. ... Population genetics is the study of the distribution of and change in allele frequencies under the influence of the four evolutionary forces: natural selection, genetic drift, mutation, and migration. ... For other uses, see Natural selection (disambiguation). ... In population genetics, genetic drift is the statistical effect that results from the influence that chance has on the success of alleles (variants of a gene). ... In population genetics, gene flow (also known as gene migration) is the transfer of alleles of genes from one population to another. ... For linguistic mutation, see Apophony. ... Evolutionary developmental biology (evolution of development or informally, evo-devo) is a field of biology that compares the developmental processes of different animals in an attempt to determine the ancestral relationship between organisms and how developmental processes evolved. ... We dont have an article called Phenotypic plasticity Start this article Search for Phenotypic plasticity in. ... Norms of reaction for two genotypes. ... Many organisms consist of modules, both anatomically and in their metabolism. ... The evolution of sex is a major puzzle in modern evolutionary biology. ... Why do almost all living things weaken and die with age? There is not yet agreement in the academic community on a single answer. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Diagram of major stages in the eyes evolution. ... For the history of humans on Earth, see History of the world. ... Anagenesis is the progressive evolution of species involving a change in gene frequency in an entire population rather than a cladogenetic branching event. ... Catagenesis is an archaic term from evolutionary biology referring to evolutionary directions that were considered retrogressive. ... Cladogenesis is an evolutionary splitting event in which each branch and its smaller branches is a clade; an evolutionary mechanism and a process of adaptive evolution that leads to the development of a greater variety of animals or plants. ... Evolutionary thought has roots in antiquity as philosophical ideas conceived during the Ancient Greek and Roman eras, but until the 18th century, biological thought was dominated by essentialism, the idea that living forms are static and unchanging in time. ... For other people of the same surname, and places and things named after Charles Darwin, see Darwin. ... The 1859 edition of On the Origin of Species First published in 1859, The Origin of Species (full title On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life) by British naturalist Charles Darwin is one of the pivotal... The modern evolutionary synthesis refers to a set of ideas from several biological specialities that were brought together to form a unified theory of evolution accepted by the great majority of working biologists. ... The gene-centered view of evolution, gene selection theory or selfish gene theory holds that natural selection acts through differential survival of competing genes, increasing the frequency of those alleles whose phenotypic effects successfully promote their own propagation. ... The evolutionary history of life and the origin of life are fields of ongoing geological and biological research. ... This article is about life in general. ... Ecological genetics is the study of genetics (itself a field of biology) from an ecological perspective. ... For the history of humans on Earth, see History of the world. ... Molecular evolution is the process of the genetic material in populations of organisms changing over time. ... Phylogenetic groups, or taxa, can be monophyletic, paraphyletic, or polyphyletic. ... Biological systematics is the study of the diversity of life on the planet earth, both past and present, and the relationships among living things through time. ... This is a list of topics in evolutionary biology and evolution. ... Life on Earth  â€¢  â€¢  | Axis scale: millions of years ago. ...

 
 

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