Question
Question: The mode of speciation mediated by geographical isolation is referred to as ...
The mode of speciation mediated by geographical isolation is referred to as
A.adaptive radiation
B.allopatric speciation
C.parapatric speciation
D.sympatric speciation
Solution
The evolutionary process by which populations evolve into distinct species is known as speciation. Geographic isolation is a type of reproductive isolation in which two populations of a species are separated by a geographic barrier, resulting in speciation.
Complete answer:
Allopatric, peripatric, parapatric, and sympatric are the four geographic modes of speciation in nature, based on the extent to which speciating populations are isolated from one another. Animal husbandry, agriculture, and laboratory experiments can all be used to artificially induce speciation.
Adaptive radiation: Adaptive radiation is a process in evolutionary biology in which organisms rapidly diversify from an ancestral species into a plethora of new forms, especially when a change in the environment makes new resources available, changes biotic interactions, or creates new environmental niches.
Allopatric speciation: Allopatric speciation, also known as geographic speciation, vicariant speciation, or the dumbbell model, is a type of speciation in which biological populations become geographically isolated from one another to the point where gene flow is prevented or hampered.
Parapatric speciation: When new species evolve in contiguous but spatially separated habitats, this is known as parapatric speciation. The populations that are diverging during parapatric speciation, unlike allopatric speciation, maintain a zone of contact and do not completely stop exchanging genes.
Sympatric speciation: Sympatric speciation occurs when a new species evolves from a surviving ancestral species while both remain in the same geographic region. Sympatric and sympatry are terms used in evolutionary biology and biogeography to describe organisms whose ranges overlap and they occur together at least in some places.
Thus, the answer is option B: allopatric speciation.
Note: Polyploidy, such as doubling of chromosome number, can cause rapid sympatric speciation, resulting in progeny that is reproductively isolated from the parent population. New species can also be created through hybridization, followed by reproductive isolation if the hybrid is favored by natural selection.