Question

When members of a population attain sexual maturity at different times preventing interbreeding, it is termed as --- isolation.
(a)Seasonal
(b)Mechanical
(c)Habitat
(d)Ethological

Answer 1

Hint: In certain species, at various times, members of a population reach sexual maturity, avoiding interbreeding. The various times suggest that during the fall, one will reach maturity, the other in the winter, and a few others in the summer or spring.

Complete answer:
The mechanisms of reproductive isolation are diverse. Seasonal isolation, mechanical isolation, ecosystem (ecological) isolation, ethological isolation, physiological isolation, etc. are isolation mechanisms that resist interspecific crosses.
All these are isolation premating meaning isolation that prevents even happening of mating.
When sexual maturity is reached by members of a population at different times to avoid interbreeding, it is called seasonal or temporal isolation.

For instance, in different seasons, the field crickets Gryllus pennsylvanicus and Gryllus veletis become sexually mature, one in spring and the other in autumn.

Additional Information: When there is a lack of sexual desire prohibiting interbreeding between the opposite sex, it is called ethological isolation.
If there is a difference in the size, shape, or position of the male and female genitalia that prevents interbreeding, it is called a mechanical barrier.
oIf two species prevent interbreeding from being ecologically or geographically isolated, it is called habitat isolation.

So, the correct answer is, ‘Seasonal’.

Note: Any biological characteristics of organisms that prevent interbreeding (and therefore the exchange of genetic material) between members of different species living in the same geographical area. These mechanisms include seasonal isolation, which does not interfere with the breeding seasons of different populations; and behavioral isolation, which ensures that mating takes place only between members of the same species through different courtship behavior in the populations. These are both examples of processes of premating. The processes of postmating include hybrid infertility and inviability.