Question

There is an island in the middle of a large river that houses a large population of ants. Damming of the river causes the island to flood and only the highest points of the island are now above water. The ants cannot swim, so are now in multiple isolated populations. Which of the following best describes this event?A. isolation by dispersalB. isolation by vicarianceC. a form of sympatric speciationD. only a rare development of polyploidy could lead to speciation in this caseE. speciation will not occur in this case because of gene flow

Answer 1

Answer:

B. isolation by vicariance

Explanation:

This is because the ant population was  divided by an external factor  causing habitat fragmentation from   disjoined distribution of the insects( ants) into different isolated population. Since the ants  from their new habitats can not cross to other isolated habitats;  and the  the whole ant population is affected not a few member of the population;  and also because the habitat fragmentation was due to natural occurrence( flooding) and not by movements of the ants by themselves   Then t is isolation by vicariance.

Therefore option B is the answer.

However if these ants  can cross from one isolated habitat to another it will be isolated by dispersal.  so  B is the answer.

Answer 2

Answer:

B. isolation by vicariance

Explanation:

Vicariance is one of the biological processes that cause the isolation of a population of a species by a geographical barrier. These geographical barriers such as river, valley, causes physical physical isolation of organisms. Over time, these subpopulations of the ants that are separated by flood, undergo speciation to form new species.