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The mechanisms of reproductive isolation are a collection of evolutionary mechanisms, behaviors and physiological processes critical for speciation.They prevent members of different species from producing offspring, or ensure that any offspring are sterile.
Ethological isolation is based on behavioral traits of pollinators that prefer different morphological characteristics of a flower either genetically or through learned behavior. These characteristics could be the overall shape and structure, color, type of nectar, or smell of the flower.
Allochronic speciation (also known as allochronic isolation, or temporal isolation) is a form of speciation (specifically ecological speciation) arising from reproductive isolation that occurs due to a change in breeding time that reduces or eliminates gene flow between two populations of a species.
The isolation of two populations of a species due to a change in breeding periods. This isolation acts as a precursor to allochronic speciation, a type of speciation which results when two populations of a species become isolated due to differences in reproductive timing. An example is the periodical 13- and 17-year Magicicada species. [3]
It is thus is a refinement of sympatric speciation, with a behavioral, rather than geographical barrier to the flow of genes among diverging groups within a population. Behavioral separation as a mechanism for promoting sympatric speciation in a heterogeneous (or patchwork landscape) was highlighted in John Maynard Smith 's seminal paper on ...
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.
[3]: 354 [4] [5] Differences in behavior or biology that inhibit formation of hybrid zygotes are termed prezygotic isolation. Reinforcement can be shown to be occurring (or to have occurred in the past) by measuring the strength of prezygotic isolation in a sympatric population in comparison to an allopatric population of the same species.
In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. [1] An initially interbreeding population that splits into two or more distinct species sharing a common range exemplifies sympatric speciation .