Portal:Evolutionary biology

The Evolutionary Biology Portal

Introduction

Evolutionary biology is a subfield of biology that analyzes the four mechanisms of evolution: natural selection, mutation, genetic drift, and gene flow. Natural selection was independently discovered as the engine of evolution by Charles Darwin and Alfred Russel Wallace, based on patterns in the geographic distribution of species. Gregor Mendel discovered the laws of heredity. R. A. Fisher unified Darwin and Mendel in the modern synthesis.

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. 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. Evolution accounts for the unity and diversity of life on Earth; Theodosius Dobzhansky famously said that nothing in biology makes sense without it. (Full article...)

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Natural selection is the differential survival and reproduction of individuals due to differences in the relative fitness endowed on them by their own particular complement of observable characteristics. It is a key law or mechanism of evolution which changes the heritable traits characteristic of a population or species over generations. Charles Darwin popularised the term "natural selection", contrasting it with artificial selection, which is intentional, whereas natural selection is not.

For Darwin, natural selection was a law or principle which resulted from three different kinds of process: inheritance, including the transmission of heritable material from parent to offspring and its development (ontogeny) in the offspring; variation, which partly resulted from an organism's own agency (see phenotype; Baldwin effect); and the struggle for existence, which included both competition between organisms and cooperation or 'mutual aid' (particularly in 'social' plants and social animals). (Full article...)

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

Image 1Reinforcement assists speciation by selecting against hybrids. (from Speciation)
Image 2The 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 3Rhagoletis pomonella, the hawthorn fly, appears to be in the process of sympatric speciation. (from Speciation)
Image 4Among 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 5Gaur (Indian bison) can interbreed with domestic cattle. (from Speciation)
Image 6Expression of homeobox (Hox) genes in the fruit fly (from Evolutionary developmental biology)
Image 7Three major single-chromosome mutations: deletion (1), duplication (2) and inversion (3). (from Mutation)
Image 8Cichlids such as Haplochromis nyererei diversified by sympatric speciation in the Rift Valley lakes. (from Speciation)
Image 9Speciation 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 10A gene regulatory network (from Evolutionary developmental biology)
Image 11Comparison of allopatric, peripatric, parapatric and sympatric speciation (from Speciation)
Image 12The 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 13Selection of disease-causing mutations, in a standard table of the genetic code of amino acids (from Mutation)
Image 14Homologous 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 15A mutation has caused this moss rose plant to produce flowers of different colours. This is a somatic mutation that may also be passed on in the germline. (from Mutation)
Image 16Gene product distributions along the long axis of the early embryo of a fruit fly (from Evolutionary developmental biology)
Image 17The 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 18Five types of chromosomal mutations (from Mutation)
Image 19Phyletic 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 20A red tulip exhibiting a partially yellow petal due to a somatic mutation in a cell that formed that petal (from Mutation)
Image 21Point mutations classified by impact on protein (from Mutation)
Image 22Embryology 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 23African pygmy kingfisher, showing coloration shared by all adults of that species to a high degree of fidelity. (from Speciation)
Image 24Prodryas persephone, a Late Eocene butterfly (from Mutation)
Image 25Gap 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)
Image 26Types of small-scale mutations (from Mutation)
Image 27A covalent adduct between the metabolite of benzo[a]pyrene, the major mutagen in tobacco smoke, and DNA (from Mutation)
Image 28The pax-6 gene controls development of eyes of different types across the animal kingdom. (from Evolutionary developmental biology)
Image 29Male Drosophila pseudoobscura (from Speciation)
Image 30A. Lancelet (a chordate), B. Larval tunicate, C. Adult tunicate. Kowalevsky saw that the notochord (1) and gill slits (5) are shared by tunicates and vertebrates. (from Evolutionary developmental biology)
Image 31Turing'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 32This figure shows a simplified version of loss-of-function, switch-of-function, gain-of-function, and conservation-of-function mutations. (from Mutation)

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Credit: Commons:User:Thomas Ihle

Tarbosaurus at the Naturkundemuseum Münster in Münster, Germany.

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Did you know... - show different entries

... that Herbert Spencer, secretary of the Derby Philosophical Society, first suggested the term "survival of the fittest" after reading Charles Darwin's idea of evolution?
... 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 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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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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