Question

different insect species may not pollinate a plant because of the shape or color of its flower this is best described as...

Part A Different insect species may not pollinate a plant O O O behavioral isolation disruptive isolation geographic isolation reproductive isolation o O structural isolation Submit Request Answer

Answer 1

Isolation- Isolation is a process due to which two species which were used to normally produce hybrid species prevented from doing so or interbreeding.

There are many types of isolation.

Option-A -Behavioural isolation:- It is a type of isolation in which members of a population vary in their behaviour with time and gradually they are unable to mate and become separate species. Example- Species with complex courtship behaviours usually show stereotyped “call and response” signals among male and female before the actual mating takes place. Suppose a particular type of bird showing a specific dancing pattern always attracts the birds of same dancing pattern for mating not the other birds showing different type of dancing pattern though belonging to same species.

This is not the correct option.

Option-B -Disruptive isolation:-This type of isolation takes place in large population when there is lots of pressure on the individuals to find advantages on niches, usually when they compete with each other for food to survive or partners to pass their genes. This usually takes place at the time of some changes like habitat change or change in resources availability.

Example of this is during industrial revolution in England when the pollution level increased due to industries, in that area the white peppered moths gradually became black or brown moths for their survival. But the same species which were found in less polluted areas were white in color. This is also not the best option.

Option-C-Geographical isolation:- it is a type of isolation among the population of animals, plants and other organisms which are separated from exchanging genetic materials with other organisms from same species due to physical barriers or in other words due to geographical barriers.

Example is a mountain range prevents, two types of goats from mating causing gene pool to have less variation in it.

So this is also not the correct option.

Option-D-Reproductive isolation:- The barriers which inhibit reproduction among species causes reproductive isolation. Reproductive isolation takes place due to ecological isolation, temporal isolation and behavioural isolation. ecological isolation- When closely related species occupy different ecosystems in their geographical region, it causes isolation among themselves for example red legged frogs breed in large ponds, yellow legged frogs breed in moving streams as a result mating cannot occur among themselves though they belong to the same species and it will lead to reproductive isolation. In temporal isolation two related species though living in the same geographical range but their period of sexual activity is different, for example closely related fruit flies in Hawaii species that is Drosophila penismilis breeds in early morning but closely related D. pseudobscura breeds in afternoon so the difference in their breeding time isolates them from interbreeding.

Option-E-Structural isolation:- In this type of isolation different structures keeps the species isolated from one another. Example in flowering plants the shape of the flower should match with the pollinator, plants which do not have correct shape for the pollinator will not receive the pollen transfer.

So this is the best option for the question which says different insect species may not pollinate a plant because of the shape or color of its flower – the correct answer for this is due to structural isolation.

Answer- option-E (Structural isolation)