Chapter 22, Problem 9U

Summary Introduction

Introduction:

The reproductive isolation is the evolutionary mechanism or behavior that prevents organism of different biological species from breeding and leads to the prevention of exchange of genetic material. There are two types of reproductive barriers: Prezygotic barrier prevents the fertilization between species and postzygotic barrier prevents the maturation of hybrid zygote formed by the mating of two different species.

Prezygotic barrier involves habitat, mechanical, gametic, behavioral, and temporal isolation. Postzygotic barriers involve reduced viability of the hybrid formed, reduced fertility of the hybrid and the breakdown of the hybrid that result in the sterile generations.