In: Biology
Reproductive isolation is a major way two new species can arise from two populations of organisms that started out as one species. Using complete sentences, give and explain FOUR ways that two populations could become reproductively isolated. Give two prezygotic barriers and two postzygotic barriers.
Different species are unable to interbreed and produce healthy, fertile offspring due to barriers called mechanisms of reproductive isolation which is of two types - prezygotic and postzygotic
Prezygotic reproductive barriers- is a mechanism that prevents fertilization from occurring. It can be of-
Habitat isolation- two species prefer different habitats to reproduce hence they rarely meet each other due to the difference in their habitats. For example, two species of crickets prefer different habitats to grow, one of them lives in sandy soil and the other preferred loamy soil. As a result, both the species stay in their habitats and rarely move to each other`s habitat making them reproductively isolated.
Behavioural isolation- two species can`t interbreed when they think that the other one is not their choice or is ugly. For example, a slight difference in the songs sung by males of two grasshopper species causes females of each species attracted only to the song of their own species.
Post zygotic barriers- is a mechanism that reduces the viability or reproductive capacity of hybrid offspring. Hybrid zygote abnormality, hybrid infertility, and low hybrid viability are postzygotic mechanisms. For example, mules result from the mating of a horse with a donkey. They are born and develop into normal healthy adult animals, but they cannot produce fertile and viable hybrids.