Question

What are the four evolutionary forces that would disrupt the population?

Answer 1

Evolution:

1. Evolution is the gradual change in the inherited traits of biological populations over many generations.
2. These traits are the expressions of genes that are transferred from parent to offspring during reproduction.
3. Because of mutation, genetic recombination, and other causes of genetic variation, different traits frequently occur within a population.
4. Evolution occurs when this variety is subjected to evolutionary processes like natural selection (including sexual selection) and genetic drift, which cause specific traits to become more or less prevalent within a population.
5. Mutation, gene flow, genetic drift, and natural selection are four such evolutionary forces.

Mutation:

1. In a gene pool, mutation produces new genetic variation.
2. It's how all new alleles get their start.
3. The mutations that matter for evolution in sexually reproducing organisms are those that occur in gametes.
4. Only these mutations can be handed down to the next generation.
5. The likelihood of a mutation in a gamete for any given gene is extremely low.
6. As a result, mutations alone have little impact on allele frequencies.

Gene flow:

1. Individuals move into or out of a population, causing gene flow.
2. The rate of migration can have a big impact on allele frequencies if it's fast.
3. Both the population they leave and the population they enter may have different allele frequencies.

Genetic Drift:

1. In a small population, genetic drift is a random change in allele frequencies.
2. Allele frequencies in the children may differ by chance from allele frequencies in the parents when a small number of parents generate a small number of kids.
3. In a small population, it's also possible that the next generation will have different allele frequencies than projected.
4. Allele frequencies may drift over time in this fashion.
5. In a small population, genetic drift is a random change in allele frequencies.

Natural Selection:

1. Natural selection affects an organism's phenotype or its traits that interact with the environment, but any phenotype having a genetic foundation (heritable) that facilitates reproduction may spread more widely in a population.
2. This process can eventually lead to speciation when populations specialize for specific ecological niches over time (microevolution) (the emergence of new species, macroevolution).
3. Modern biology is built around the concept of natural selection.
4. He compared natural selection to artificial selection, which is the systematic favouring of animal and plant reproduction for features deemed desirable by human breeders.
5. While random genetic drift can cause genotypes to progressively shift, natural selection continues to be the main mechanism for adaptive evolution.