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...)

Read more...

Show new selections below (purge)

edit watch

Selected article - show another

In evolutionary biology, punctuated equilibrium (also called punctuated equilibria) is a theory that proposes that once a new species appears in the fossil record, the population will become stable, showing little evolutionary change for most of its geological history. This state of little or no morphological change is called stasis. When significant evolutionary change occurs, the theory proposes that it is generally restricted to rare and geologically rapid events of branching speciation called cladogenesis. Cladogenesis is the process by which a species splits into two distinct species, rather than one species gradually transforming into another.

Punctuated equilibrium is commonly contrasted with phyletic gradualism, the idea that evolution generally occurs uniformly by the steady and gradual transformation of whole lineages (anagenesis). (Full article...)

List of selected articles

edit watch

General images - load new batch

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

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

edit watch

Selected picture - show another

Credit:

The Golden Toad was last seen on May 15, 1989. Decline in amphibian populations is ongoing worldwide.

More selected pictures

Read more...

edit watch

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 the evolution of sex is a major puzzle of evolutionary biology, due to the so-called two-fold cost of sex?
... 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?

More did you know facts

edit watch

Related portals

Related subjects

Topics in biology

edit watch

Tasks you can do

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...)
Nominate and vote: Science collaboration of the month, Article Improvement Drive

edit watch

WikiProjects

A complete list of scientific WikiProjects can be found here. See also Wikispecies, a Wikimedia project dedicated to classification of biological species.

edit watch

Associated Wikimedia

Evolutionary biology on Wikinews	Evolutionary biology on Wikiquote	Evolutionary biology on Wikibooks	Evolutionary biology on Wikisource	Evolutionary biology on Wiktionary	Evolutionary biology on Wikimedia Commons
News	Quotations	Manuals & Texts	Texts	Definitions	Images & Media