Question

Identify the processes that can cause evolution in a population. Which of these results in an increase in the number of alleles at a locus and which result in a decrease in the number of alleles at a locus? Which cause populations to become different from each other and which cause populations to become more similar?

Answer 1

One mechanism that drives evolution is natural selection, which is a process that increases the frequency of advantageous alleles in a population. Natural selection results in organisms that are more likely to survive and reproduce.

Random changes in allele frequency result in the change in relative allele frequency, called genetic drift. This can either increase or decrease by chance over time. Once it begins, genetic drift will continue until the involved allele is either lost by a population or is the only allele present at a particular gene locus within a population. Genetic drift can result in the loss of rare alleles and can decrease the size of the gene pool. Genetic drift can also cause a new population to be genetically distinct from its original population, which has led to the hypothesis that genetic drift plays a role in the evolution of new species.

Eventually, genetic drift can cause a subpopulation to become genetically distinct from its original population.

Evolution by means of natural selection is the process by which traits that enhance survival and reproduction become more common in successive generations of a population.