Allopatric speciation
Allopatric speciation (also allopatric speciation or speciation through spatial separation ) (Greek άλλος allos "foreign" and Πάτρα patra "home") is considered to be one of the main causes of speciation . It can occur when the range of a species is split into two or more parts by external processes such as mountain formation , continental drift , climate change or the exclusion of competition .
The subpopulations are then not subject to exactly the same selection factors and the associated selection pressures are also different. Due to the geographical isolation in the separate parts of the distribution area , they develop increasingly independently of one another. If the genetic differences become so great that the individuals of the two regional stocks can no longer produce fertile offspring, the original species has allopatricically split into two or more new species.
In biology, allopatry is the non-overlap (complete spatial separation) of the distribution areas of species , subspecies or populations . In the case of allopatric distribution, geographic isolation (separation) prevents encounters and crossings in the wild. If the distribution areas are immediately adjacent but do not overlap, one speaks of parapatric distribution. Allopatry also describes the freedom from overlap of habitats of different species or groups.
The contrast to allopatry is represented by sympatry , in which closely related species, subspecies or populations occur in the same geographical area and thus there is the possibility of meeting and crossing.
A special case of allopatric speciation that is important in practice is when speciation is due to the isolation of a very small subpopulation, e.g. On an island, declining from a much larger mother population. When such a founder population is founded, the founder effect leads to gene drift , which often results in a rapid shift in characteristics. The emergence of new species is likely to be much easier under such conditions.
See also
Individual evidence
- ^ Neil A. Campbell, Jane B. Reece: Campbell Biology. Upper secondary school. 2011. p. 316. ISBN 978-3-86894-900-1