[Campbell Biology P.26] Which of the following scenarios is most directly responsible for t... | Practice Question

Which of the following scenarios is most directly responsible for the establishment of reproductive isolation between two populations?

  • A: Accumulation of genetic differences due to independent evolution in geographically separated populations.
  • B: Formation of physical barriers preventing gene flow between populations.
  • C: Development of intrinsic pre-zygotic or post-zygotic barriers that prevent successful interbreeding or produce sterile offspring.
  • D: Competition for limited resources within a shared habitat.

Explanation

Reproductive isolation refers specifically to the existence of biological factors barriers that impede members of two species from producing viable, fertile offspring. These barriers can be pre-zygotic e.g., habitat isolation, behavioral isolation, mechanical isolation, gametic isolation or post-zygotic e.g., reduced hybrid viability, reduced hybrid fertility, hybrid breakdown . While genetic divergence, geographic isolation, and competition can all contribute to or precede reproductive isolation, the direct cause is the development of these intrinsic biological mechanisms that prevent successful gene flow.