Search results
Results from the WOW.Com Content Network
All forms of natural speciation have taken place over the course of evolution; however, debate persists as to the relative importance of each mechanism in driving biodiversity. [ 26 ] One example of natural speciation is the diversity of the three-spined stickleback , a marine fish that, after the last glacial period , has undergone speciation ...
A prerequisite for natural selection to result in adaptive evolution, novel traits and speciation is the presence of heritable genetic variation that results in fitness differences. Genetic variation is the result of mutations, genetic recombinations and alterations in the karyotype (the number, shape, size and internal arrangement of the ...
Evolution is the change in the heritable characteristics of biological populations over successive generations. [1] [2] It occurs when evolutionary processes such as natural selection and genetic drift act on genetic variation, resulting in certain characteristics becoming more or less common within a population over successive generations. [3]
Evolutionary biology is the subfield of biology that studies the evolutionary processes such as natural selection, common descent, and speciation that produced the diversity of life on Earth.
This process of speciation influenced by natural selection is reinforcement, and can happen under any mode of speciation [3]: 355 (e.g. geographic modes of speciation or ecological speciation [21]). It necessitates two forces of evolution that act on mate choice: natural selection and gene flow. [22]
Mayr's definition has gained wide acceptance among biologists, but does not apply to organisms such as bacteria, which reproduce asexually. Speciation is the lineage-splitting event that results in two separate species forming from a single common ancestral population. [15] A widely accepted method of speciation is called allopatric speciation.
The discipline of biology that studies the evolution of biological organisms and the processes by which it operates, including natural selection, adaptation, common descent, and speciation. A core element of the modern synthesis , evolutionary biology integrates concepts from genetics , systematics , ecology , paleontology , developmental ...
Allopatric speciation, in which two populations of the same species are geographically isolated from one another by an extrinsic barrier and evolve intrinsic (genetic) reproductive isolation. Peripatric speciation, in which a small group of a population is separated from the main body and experiences genetic drift.