Search results
Results from the WOW.Com Content Network
Four main types of population pairs exist in nature. Sympatric populations (or species) contrast with parapatric populations, which contact one another in adjacent but not shared ranges and do not interbreed; peripatric species, which are separated only by areas in which neither organism occurs; and allopatric species, which occur in entirely distinct ranges that are neither adjacent nor ...
Much of the controversy concerning sympatric speciation may lie solely on an argument over what sympatric divergence actually is. The use of different definitions by researchers is a great impediment to empirical progress on the matter. The dichotomy between sympatric and allopatric speciation is no longer accepted by the scientific community.
Allopatric speciation (from Ancient Greek ἄλλος (állos) 'other' and πατρίς (patrís) 'fatherland') – also referred to as geographic speciation, vicariant speciation, or its earlier name the dumbbell model [1]: 86 – is a mode of speciation that occurs when biological populations become geographically isolated from each other to an extent that prevents or interferes with gene flow.
There are four geographic modes of speciation in nature, based on the extent to which speciating populations are isolated from one another: allopatric, peripatric, parapatric, and sympatric. Whether genetic drift is a minor or major contributor to speciation is the subject of much ongoing discussion.
A simplification of an allopatric speciation experiment where two lines of fruit flies are raised on maltose and starch media. Laboratory experiments of speciation have been conducted for all four modes of speciation: allopatric, peripatric, parapatric, and sympatric; and various other processes involving speciation: hybridization, reinforcement, founder effects, among others.
Marine iguana of the Galapagos Islands evolved via allopatric speciation, through limited gene flow and geographic isolation. While gene flow can greatly enhance the fitness of a population, it can also have negative consequences depending on the population and the environment in which they reside. The effects of gene flow are context-dependent.
Males in sympatric populations of the damselflies Calopteryx maculata and C. aequabilis are able to discriminate between females of different species better than those in allopatric populations; with females of C. aequabilis in sympatric populations exhibiting lighter wing colors compared to allopatric females—an illustration of reproductive ...
Reproductive isolation can be caused by allopatric speciation. A population of Drosophila was divided into sub populations selected to adapt to different food types. After some generations the two sub populations were mixed again. Subsequent matings occurred between individuals belonging to the same adapted group. [84]