Mechanisms for Evolution

A type of genetic drift in which small groups of organisms separate from a larger population and form new small colonies.

• Gene Flow

• Founder Effect

• Natural Selection

• Artificial Selection

The exchange of genes between two populations through immigration or emigration.

• Genetic Drift

• Founder Effect

• Gene Flow

• Genetic Recombination

This term refers to the total genetic information found in a population; the complete collection of all the alleles found in a population

• Gene library

• Genome

• Gene pool

• Allele pool

This is one of the mechanisms of evolution; it is a continuous process in which organisms with traits that make them better-adapted to their environment are more likely to survive and reproduce than organisms without such adaptations

• Directional selection

• Microevolution

• Gene flow / genetic drift

• Natural selection

This is a pattern of natural selection where one extreme form of a trait is more advantageous than the average or the opposite extreme; as a result, this trait in the population tends to evolve towards that one extreme

• Directional selection

• Disruptive selection

• Stabilizing selection

• Forward selection

This is the pattern of natural selection where BOTH of the extreme versions of a trait are more advantageous than the average, so a population evolves in both directions away from the average

• Directional Selection

• Disruptive Selection

• Stabilizing Selection

• Radical Selection

This occurs when a large population is drastically reduced by an event such as a natural disaster; the population's new gene pool only contains alleles from the survivors

• Founder effect

• Bottleneck effect

• Meteor effect

• Natural selection

This is the process that ultimately creates new variations and changes in DNA; leads to the creation of new alleles

• Mutation

• Microevolution

• Natural selection

• Gene flow / genetic drift

This is a pattern of natural selection in which the average (or intermediate) form of a trait is the most advantageous, and so a population evolves away from the extremes and toward the average

• Disruptive selection

• Directional selection

• Stabilizing selection

• Middle selection

The rock pocket mouse is a species of mouse that lives among the rocky outcroppings in the deserts of the Southwestern US. Researchers have observed that it is advantageous for these mice to have either a very dark or a very light fur color; this is because the very light color allows them to hide among light-colored rocks, and the very dark color allows them to hide among darker, volcanic rocks. The intermediate-colored mice cannot hide as well on either type of rock, and so are at a disadvantage. What type/pattern of natural selection would you expect to occur here?

• Stabilizing selection

• Disruptive selection

• Directional selection

• None of these are correct