Question

Suppose that a few individuals of a lizard species are transported on a log that floats from the mainland, where the lizard is abundant, to a distant island, where prior to this event no lizards (of any species) existed. The environmental conditions on the island are similar to those on the mainland. A small population of this lizard becomes established on the island; within a few years, allele frequencies in the island population differ greatly from those in mainland populations. Which of the following is the most likely cause of the genetic differences between the island and mainland populations?

A. natural selection
B. genetic drift
C. mutation
D. gene flow

Answer 1

The correct answer is B. genetic drift.

Step-by-step explanation:

Genetic drift, also known as gene drift, is an evolutionary force that acts together with natural selection by changing the allelic frequencies of species over time. It is a stochastic effect that is a consequence of random sampling in reproduction and the loss of alleles by chance and not by natural selection. It is a random change in the frequency of alleles from one generation to another. Normally there is a loss of the less frequent alleles and a fixation (frequency close to 100%) of the most frequent, resulting in a decrease in the genetic diversity of the population.