Darwin's finches on the Galápagos Islands illustrate
- Acheck_circle
Adaptive radiation: a single ancestral species diversified into ~14 species filling different niches (different beak shapes for different food)
- B
Genetic drift alone: random fluctuations in small isolated populations, without selection on diet, produced the full range of beak shapes seen across the islands
- C
Hybridization: several distinct mainland species repeatedly interbred on the islands, producing a continuous gradient of beak shapes rather than discrete species
- D
Convergent evolution: unrelated finch-like lineages independently colonized each island and evolved similar beak shapes for similar foods (no shared finch ancestor)
Explanation
Different islands and food sources selected for different beak morphologies; allopatric speciation followed by adaptive radiation.