What must occur for the gene pool within a population change?

Answer 1

Natural Selection/Genetic Drift

Answer 2

1. Genetic Drift: This represents random changes in small gene pools due to sampling errors in propagation of alleles. The bottleneck effect and founder effect are prime examples of genetic drift. In either case the number of individuals in a population is drastically reduced distorting the original allelic frequencies.

2. Gene Flow: The movement of alleles into and out of a gene pool. Migration of an organism into different areas can cause the allelic frequencies of that population to increase. Most populations are not isolated, which is contrary to the Hardy-Weinberg Theorem.

3. Mutations: These changes in the genome of an organism are an important source of natural selection.

4. Nonrandom mating: Inbreeding is a popular form of nonrandom mating. Individuals will mate more frequently with close individuals than more distant ones. Assortive mating, is another form of nonrandom mating. Here the individuals will mate with partners that closely resemble themselves in certain characteristics.

5. Natural Selection: Populations vary in the types of individuals and their reproductive success. Those individuals who leave more offspring behind than others, pass on more of their alleles and have a better success rate in dominating the population.

Answer 3

For the gene pool within a population to change, factors such as genetic mutations, gene flow (migration of individuals in or out), genetic drift (random changes in gene frequencies), natural selection, and non-random mating must be at play. These processes can alter the frequency of alleles in the population over time, causing changes in the gene pool.

Answer 4

A gene pool must have lots of variation in the genotypes and phenotypes before the formation of species.