Question

An island has a population of 100,000 moths that has 98% gray individuals and 2% black individuals. Generation after generation, this ratio and population size remains basically the same. After a shift in weather and wind patterns, 10,000 black moths from the mainland population are blown onto the island and begin mating with the moths that were already on the island, leading to a change in allele frequency of the island population. This is an example of____________.

Answer 1

The introduction of black moths from the mainland to an island population, resulting in altered allele frequencies, exemplifies gene flow, which occurs due to migration and mixing of populations.

Step-by-step explanation:

The situation described where an island population of moths is altered by the introduction of a large number of black moths from the mainland is an example of gene flow. Gene flow occurs when individuals or their gametes migrate from one population to another and alter the genetic composition of the receiving population. In this case, the black moths from the mainland mix with the island population, introducing new alleles thereby changing the allele frequency of the island's moth population.

It's important to recognize that this scenario does not align with the concept of genetic drift, which is a random change in allele frequencies often having a more significant effect in small populations. Since the introduction of new individuals to the island is due to migration and mating, not chance, genetic drift is not the main evolutionary mechanism at play here. While the original island population had a ratio of 98% gray to 2% black, this ratio will change following the mixing with the mainland black moths.