**Geographical (allopatric) speciation** occurs when:
ATwo populations interbreed freely
BA population is split by a geographical barrier (river, mountain, ocean), preventing gene flow → divergence → new species
CSpeciation happens within a single freely-mixing population
DHybrids replace parental species
Answer & Solution
Correct answer: B. A population is split by a geographical barrier (river, mountain, ocean), preventing gene flow → divergence → new species
Allopatric speciation requires geographical isolation (mountain uplift, river formation, continental drift). Each isolated population accumulates distinct mutations and adapts to its niche — eventually they become reproductively incompatible. Classic example: Darwin's finches on different Galápagos islands.
Related questions
Which of the following best illustrates **convergent evolution** (analogous structures ari**Ribozymes** are:Weismann's experiment of cutting rat tails for 21 generations disproved the theory of:Which of the following is **not** a force that changes allele frequencies (causing evoluti**Adaptive radiation** refers to:Which of these is a **post-zygotic** reproductive isolating mechanism?In a population, 16% individuals show a recessive phenotype (aa). Under Hardy-Weinberg, thIn a Hardy-Weinberg population, if the frequency of the recessive allele $a$ is $q = 0.3$,