Which ecological process allows movement of genes among populations across habitat patches?

• A. Gene flow
• B. Genetic drift
• C. Mutation
• D. Bottleneck

Answer: (A)

Gene flow is the movement of genetic material between populations when individuals or their gametes migrate and breed across habitat patches. This process transfers alleles from one population into another, making neighboring patches more genetically similar and preventing them from diverging too much. For example, a mammal moving through a corridor and breeding in a neighboring patch carries its genes into that local gene pool, spreading alleles. The other processes describe changes within a population rather than transfer between populations: genetic drift is random fluctuation of allele frequencies, often in small groups; mutation introduces new alleles within a population and doesn’t automatically move them to other populations; a bottleneck is a sharp reduction in population size that can reduce genetic variation and shift allele frequencies, not movement between patches.