Henry was studying two populations of the same species of lizards. one population lived on an island and the other lived on the mainland. both populations were affected by a hurricane that hit the island and the mainland with equal force. a year later, henry was testing the gene frequency and saw a decrease in genetic variation in the island species, but not in the mainland species. which best describes a conclusion he might have reached?

gene flow greatly affects small populations, but large populations can recover.
genetic drift greatly affects small populations, but large populations can recover.
gene flow greatly affects large populations, but small populations can recover.
genetic drift greatly affects large populations, but small populations can recover.

The correct answer would be Genetic drift greatly affects small populations, but large populations can recover.

Genetic variation is one of the mechanisms of evolution due to which the allellic frequency of a population changes as a result of random sampling of the organisms.

It may result in the loss of the genetic variation or alleles in a population.

Its results are maximum when the population size is small as they are more susceptible to the random changes.

In addition, its effects are increased when the population size is adversely reduced due to a natural disaster.

1) gene flow

- it is described as the transfer of genes from one population to another population so that frequency of gene is increased.

-a zebra migrates to join a different herd of zebras.

2) natural selection

- a mechanism of evolutionary change in which individuals with advantageous traits survive and reproduce whereas the others ( those that can not adapt) eliminate from the population.

-competition for sunlight leads to taller trees.

3) mutation

- permanent change in the nucleotide sequence of dna ( genetic material) that could have harmful or useful consequences.

-the dna of a snake changes to make its venom stronger.

4) genetic drift - it is a random phenomenon ( that occurs by chance such as fire) that results in change in the gene frequency in a small population.    

-a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

explanation:

a. to encourage apoptosis