Portal:Evolutionary biology

Image 1A covalent adduct between the metabolite of benzo[a]pyrene, the major mutagen in tobacco smoke, and DNA (from Mutation)

Image 2Comparison of allopatric, peripatric, parapatric and sympatric speciation (from Speciation)

Image 3A 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 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 5Male Drosophila pseudoobscura (from Speciation)

Image 6Gaur (Indian bison) can interbreed with domestic cattle. (from Speciation)

Image 7Rhagoletis pomonella, the hawthorn fly, appears to be in the process of sympatric speciation. (from Speciation)

Image 8The 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 9The pax-6 gene controls development of eyes of different types across the animal kingdom. (from Evolutionary developmental biology)

Image 10Gene product distributions along the long axis of the early embryo of a fruit fly (from Evolutionary developmental biology)

Image 11Homologous 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 12Embryology 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 13Selection of disease-causing mutations, in a standard table of the genetic code of amino acids (from Mutation)

Image 14The 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 15A gene regulatory network (from Evolutionary developmental biology)

Image 16Expression of homeobox (Hox) genes in the fruit fly (from Evolutionary developmental biology)

Image 17Cichlids such as Haplochromis nyererei diversified by sympatric speciation in the Rift Valley lakes. (from Speciation)

Image 18Phyletic 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 19Types of small-scale mutations (from Mutation)

Image 20This figure shows a simplified version of loss-of-function, switch-of-function, gain-of-function, and conservation-of-function mutations. (from Mutation)

Image 21A. 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 22Five types of chromosomal mutations (from Mutation)

Image 23The 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 24Point mutations classified by impact on protein (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 26Speciation 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 27African pygmy kingfisher, showing coloration shared by all adults of that species to a high degree of fidelity. (from Speciation)

Image 28Prodryas persephone, a Late Eocene butterfly (from Mutation)

Image 29Reinforcement assists speciation by selecting against hybrids. (from Speciation)