Portal:Evolutionary biology

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Introduction

Evolutionary biology is the subfield of biology that studies the evolutionary processes (natural selection, common descent, speciation) that produced the diversity of life on Earth. It is also defined as the study of the history of life forms on Earth. Evolution holds that all species are related and gradually change over generations. In a population, the genetic variations affect the phenotypes (physical characteristics) of an organism. These changes in the phenotypes will be an advantage to some organisms, which will then be passed on to their offspring. Some examples of evolution in species over many generations are the peppered moth and flightless birds. In the 1930s, the discipline of evolutionary biology emerged through what Julian Huxley called the modern synthesis of understanding, from previously unrelated fields of biological research, such as genetics and ecology, systematics, and paleontology.

The investigational range of current research has widened to encompass the genetic architecture of adaptation, molecular evolution, and the different forces that contribute to evolution, such as sexual selection, genetic drift, and biogeography. Moreover, the newer field of evolutionary developmental biology ("evo-devo") investigates how embryogenesis is controlled, thus yielding a wider synthesis that integrates developmental biology with the fields of study covered by the earlier evolutionary synthesis. (Full article...)

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Title page of the 1859 edition

On the Origin of Species (or, more completely, On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life) is a work of scientific literature by Charles Darwin that is considered to be the foundation of evolutionary biology. It was published on 24 November 1859. Darwin's book introduced the scientific theory that populations evolve over the course of generations through a process of natural selection although Lamarckism was also included as a mechanism of lesser importance. The book presented a body of evidence that the diversity of life arose by common descent through a branching pattern of evolution. Darwin included evidence that he had collected on the Beagle expedition in the 1830s and his subsequent findings from research, correspondence, and experimentation.

Various evolutionary ideas had already been proposed to explain new findings in biology. There was growing support for such ideas among dissident anatomists and the general public, but during the first half of the 19th century the English scientific establishment was closely tied to the Church of England, while science was part of natural theology. Ideas about the transmutation of species were controversial as they conflicted with the beliefs that species were unchanging parts of a designed hierarchy and that humans were unique, unrelated to other animals. The political and theological implications were intensely debated, but transmutation was not accepted by the scientific mainstream. (Full article...)

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The following are images from various evolutionary biology-related articles on Wikipedia.

Image 1Prodryas persephone, a Late Eocene butterfly (from Mutation)
Image 2Point mutations classified by impact on protein (from Mutation)
Image 3Phyletic gradualism, above, consists of relatively slow change over geological time. Punctuated equilibrium, bottom, consists of morphological stability and rare, relatively rapid bursts of evolutionary change. (from Speciation)
Image 4Embryology theories of Ernst Haeckel, who argued for recapitulation of evolutionary development in the embryo, and Karl Ernst von Baer's epigenesis (from Evolutionary developmental biology)
Image 5The lac operon. Top: repressed. Bottom: active.
1: RNA Polymerase, 2: Repressor, 3: Promoter, 4: Operator, 5: Lactose, 6–8: protein-encoding genes, controlled by the switch, that cause lactose to be digested (from Evolutionary developmental biology)
Image 6Comparison of allopatric, peripatric, parapatric and sympatric speciation (from Speciation)
Image 7Expression of homeobox (Hox) genes in the fruit fly (from Evolutionary developmental biology)
Image 8Male Drosophila pseudoobscura (from Speciation)
Image 9A. Lancelet (a chordate), B. Larval tunicate, C. Adult tunicate. Kowalevsky saw that the notochord (1) and gill slit (5) are shared by tunicates and vertebrates. (from Evolutionary developmental biology)
Image 10Cichlids such as Haplochromis nyererei diversified by sympatric speciation in the Rift Valley lakes. (from Speciation)
Image 11Turing's 1952 paper explained mathematically how patterns such as stripes and spots, as in the giant pufferfish, may arise, without molecular evidence. (from Evolutionary developmental biology)
Image 12A gene regulatory network (from Evolutionary developmental biology)
Image 13The distribution of fitness effects (DFE) of mutations in vesicular stomatitis virus. In this experiment, random mutations were introduced into the virus by site-directed mutagenesis, and the fitness of each mutant was compared with the ancestral type. A fitness of zero, less than one, one, more than one, respectively, indicates that mutations are lethal, deleterious, neutral, and advantageous. (from Mutation)
Image 14Among the centipedes, all members of the Geophilomorpha are constrained by a developmental bias to have an odd number of segments, whether as few as 27 or as many as 191. (from Evolutionary developmental biology)
Image 15Mutation with double bloom in the Langheck Nature Reserve near Nittel, Germany (from Mutation)
Image 16Rhagoletis pomonella, the hawthorn fly, appears to be in the process of sympatric speciation. (from Speciation)
Image 17Gene product distributions along the long axis of the early embryo of a fruit fly (from Evolutionary developmental biology)
Image 18Gaur (Indian bison) can interbreed with domestic cattle. (from Speciation)
Image 19A mutation has caused this moss rose plant to produce flowers of different colors. This is a somatic mutation that may also be passed on in the germline. (from Mutation)
Image 20A red tulip exhibiting a partially yellow petal due to a somatic mutation in a cell that formed that petal (from Mutation)
Image 21Selection of disease-causing mutations, in a standard table of the genetic code of amino acids (from Mutation)
Image 22Five types of chromosomal mutations (from Mutation)
Image 23This figure shows a simplified version of loss-of-function, switch-of-function, gain-of-function, and conservation-of-function mutations. (from Mutation)
Image 24Reinforcement assists speciation by selecting against hybrids. (from Speciation)
Image 25Homologous hox genes in such different animals as insects and vertebrates control embryonic development and hence the form of adult bodies. These genes have been highly conserved through hundreds of millions of years of evolution. (from Evolutionary developmental biology)
Image 26The pax-6 gene controls development of eyes of different types across the animal kingdom. (from Evolutionary developmental biology)
Image 27The structure of a eukaryotic protein-coding gene. A mutation in the protein coding region (red) can result in a change in the amino acid sequence. Mutations in other areas of the gene can have diverse effects. Changes within regulatory sequences (yellow and blue) can effect transcriptional and translational regulation of gene expression. (from Mutation)
Image 28African pygmy kingfisher, showing coloration shared by all adults of that species to a high degree of fidelity. (from Speciation)
Image 29Speciation via polyploidy: A diploid cell undergoes failed meiosis, producing diploid gametes, which self-fertilize to produce a tetraploid zygote. In plants, this can effectively be a new species, reproductively isolated from its parents, and able to reproduce. (from Speciation)
Image 30A covalent adduct between the metabolite of benzo[a]pyrene, the major mutagen in tobacco smoke, and DNA (from Mutation)
Image 31Types of small-scale mutations (from Mutation)
Image 32Gap genes in the fruit fly are switched on by genes such as bicoid, setting up stripes across the embryo which start to pattern the body's segments. (from Evolutionary developmental biology)

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Credit: Commons:User:David Monniaux

Tyrannosaurus rex skull at Palais de la Découverte in Paris.

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Did you know... - show different entries

... that Perfect Imperfection, a 2004 science fiction novel by Polish writer Jacek Dukaj, raises the issues of technological singularity, transhumanism and the anthropic principle, and presents a unique model of human evolution?
... that William King Gregory, a leading authority on vertebrate evolution and the preeminent expert on human dentition, was initially taken in by the Piltdown Man, a hoax which was purported to be an early human?
... that Variation and Evolution in Plants is one of the four canonical texts of the modern evolutionary synthesis and that all four texts were compiled following the authors' presentation of the Jesup Lectures at Columbia University?

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Improve: List of prehistoric mammals, List of extinct plants, Holocene extinction event
Stubs: Acritarch | Analogy (biology) | Evolutionary arms race | Genetic erosion | Hoyle's fallacy | Macromutation | Maladaptation | Evolutionary graph theory | Evolutionary landscape | Evolutionary taxonomy | Landrace | Law of Life (more...)
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A complete list of scientific WikiProjects can be found here. See also Wikispecies, a Wikimedia project dedicated to classification of biological species.

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