Question

geographical and reproductive isolation of organisms gradually leads speciation

Answer 1

Yes, the reason is the difference in their adaptation in the environment they are living in. As different geographical locations have different climate.
Moreover, reproductive isolation leads to different kinds of close relatives to interbreed.

Answer 2

Answer:

Explanation:

Speciation may be defined as an evolutionary process, which involves the formation of one or more species from an existing species. In order to understand speciation, let us consider the example of beetles. Let us consider that a population of beetles has split into two separate populations, which cannot reproduce with each other.

These two separate populations of beetles are spread on a wide mountain range since their food is widely distributed. Hence, the population of beetles in that area is very large. Beetles are small insects, which cannot travel to far off places. They gather food from nearby places. As a result, sub-populations of beetles are spread over that area. These sub-populations can lead to the formation of an entirely new species.

Geographical isolation: Since this population of beetles is spread over a large area, reproduction cannot occur between individuals of sub-populations. Reproduction will only occur within a sub-population, which will lead to the production of a new species. Now, if a river starts flowing between the two populations, then the two sub-populations would be further isolated and the chances of gene flow or reproduction further decreases.

Genetic drift and natural selection: Genetic drift and natural selection can give rise to different changes in sub-populations. For example, a particular sub-population of beetles evolves to blue or green colour due to natural selection or genetic drift. This will result in changes in subsequent generations. Thus, the two populations of beetles become completely different from each other.

These sub-populations will eventually be incapable of reproducing with each other. For example, the green female beetles of an area will prefer to reproduce with the green males only because green beetles have the survival advantage. Therefore, this results in the formation of a new species of green beetles, which are reproductively isolated.