Question

One of the important consequences of geographical isolation is:
(A) Random creation of new species.
(B) No change in the isolated fauna.
(C) Preventing speciation.
(D) Speciation through reproductive isolation.

Answer 1

Hint: Geographical isolation meant the separation of a population's members physically. When populations' native environment is divided, populations may actually become physically isolated. For instance, when fresh land or water boundaries appear.
Step by step solution:
Geographic separation causes two populations of the same species to become genetically isolated from one another. Despite sharing the same habitat and being subject to comparable environmental selection forces, two populations of the same species can diverge genetically. Geographic isolation has been shown to support divergent evolution that gives rise to distinctive phenotypes. The interfertility of morphologically dissimilar populations is frequently discovered, and the existence of reproductive isolation within nominal morphological species reveals the existence of cryptic species. Geographic isolation happens when two communities are divided by physical features like rivers, mountains, or aquatic bodies. For instance, the Kaibab squirrel, a subspecies of Abert's squirrel, emerged as a result of a tiny population becoming isolated on the Grand Canyon's north rim. A crucial component of allopatric speciation is geographic isolation. Geographical barriers can stop gene flow for long enough to allow populations to evolve separately and eventually give rise to new species. Geographic speciation sometimes referred to as allopatric speciation, is the process of biological populations of the same species becoming isolated because of geographic changes like the formation of mountains or social changes like emigration.
A lineage-splitting process known as speciation is employed to create two or more distinct species. Geographic isolation brought on by natural disasters and climatic changes, as well as a decrease in gene flow, all contribute to the process. Speciation through reproductive isolation is one of the main effects of geographic isolation.
Hence, option (D) is correct.
Note: Islands are the perfect example of allopatric speciation, in which members of an original species develop enough genetic differences due to geographic isolation to prohibit them from reproducing with one another when they are reunited.