Explain how the establishment of wildlife corridors can increase the genetic diversity of isolated populations.

IB DP Biology Higher Level (2023 syllabus) — A4.2 Conservation of biodiversity · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Model answer (4 marks)

Wildlife corridors physically connect isolated habitat patches, allowing individuals to move between them.
Movement of individuals enables gene flow or inter‑breeding between previously isolated populations.
Gene flow introduces new alleles into each population, increasing the number and variety of alleles in the gene pool.
Increased genetic diversity reduces the risk of inbreeding depression and improves the population’s adaptive potential and resilience to environmental change.

Examiner tips

Use the word "gene flow" explicitly; examiners look for the mechanism. Show the causal chain: corridor → movement → gene flow → new alleles → higher diversity. Mention the benefit to the population (inbreeding depression, resilience).

Common mistakes

Confusing corridors with just habitat restoration; they must be physically connected. Failing to link gene flow to the introduction of new alleles. Omitting the final benefit of increased diversity (e.g., reduced inbreeding).

Mark scheme (4 marks)

Wildlife corridors physically connect isolated habitat patches, allowing individuals to move between them.
Movement of individuals enables gene flow / interbreeding between previously isolated populations.
Gene flow introduces new alleles into each population, increasing the number / variety of alleles in the gene pool.
Increased genetic diversity reduces the risk of inbreeding depression and improves the population's adaptive potential / resilience to environmental change.

Key terms in this question

wildlife corridor · genetic diversity