Which mechanism best describes habitat isolation preventing gene flow between two populations living in different environments?

Which mechanism best describes habitat isolation preventing gene flow between two populations living in different environments?

• A. Habitat isolation (prezygotic)
• B. Genetic drift
• C. Founder effect
• D. Hybrid sterility

Answer: (A)

Habitat isolation is a prezygotic barrier that stops gene flow by keeping populations in different environments from meeting to mate. When two groups occupy distinct habitats, their chances of encountering each other are greatly reduced, so mating between them is unlikely and gene exchange is minimized. This ecological separation directly limits interbreeding before any fertilization can occur, which is why it best describes how habitat differences prevent gene flow. Genetic drift and the founder effect are random changes in allele frequencies within populations and don’t inherently prevent mating between already separated groups. Hybrid sterility is a postzygotic barrier that comes into play after mating has occurred, affecting the viability or fertility of hybrids rather than preventing the initial mating.

Habitat isolation is a prezygotic barrier that stops gene flow by keeping populations in different environments from meeting to mate. When two groups occupy distinct habitats, their chances of encountering each other are greatly reduced, so mating between them is unlikely and gene exchange is minimized. This ecological separation directly limits interbreeding before any fertilization can occur, which is why it best describes how habitat differences prevent gene flow.

Genetic drift and the founder effect are random changes in allele frequencies within populations and don’t inherently prevent mating between already separated groups. Hybrid sterility is a postzygotic barrier that comes into play after mating has occurred, affecting the viability or fertility of hybrids rather than preventing the initial mating.