APES unit 3

Biological Evolution

Organisms change from generation to generation through changes in their genetic material.

Gene pool

The total collection of genes in a population.

Gradualism

Evolution occurs through small incremental changes over a long period of time.

Punctuated Equilibrium

Long periods of stability interrupted by brief periods of rapid change.

Microevolution

Evolutionary changes within a species/small group of organisms usually over a short period of time.

Macroevolution

Large-scale changes that result after the formation of a new species over a long period of time.

Background Extinction

Normal, low-level rate of extinction that occurs naturally throughout Earth’s history.

Mass Extinction

Widespread, rapid decrease in biodiversity.

Founder Effect

A small group of organisms establishes a new population with a different gene pool from the original population.

Bottleneck

Sharp reduction in the size of a population sometimes caused by a natural disaster that drastically reduces genetic diversity.

Artificial Selection

Human-directed breeding to promote desirable traits.

Natural Selection

Organisms with favorable traits are more likely to survive and reproduce.

Genetic Drift

Random changes in the frequency of alleles, often in small populations, happens quickly.

Allopatric Speciation

Speciation that occurs when a population is geographically isolated.

Sympatric Speciation

Occurs in the same geographical area, but usually results from a change in behavior or ecological difference.

Biodiversity

The variety of life in a particular habitat or ecosystem.

Fitness

The ability of an organism to survive and reproduce in its environment.

Directional Selection

Favors one extreme in a trait.

Stabilizing Selection

Favors the average individuals in a trait.

Disruptive Selection

Favors both extremes in a trait.

Simpson’s Diversity Index

Measure of diversity that accounts for both species richness and evenness.

Endangered Species Act

Law aimed at preventing species from going extinct.

Alleles

Different versions of a gene.

Invasive Species

Non-native species that spread rapidly in a new environment, usually damaging it.

Biological Corridors

Areas that connect different ecosystems, allowing species to migrate and maintain genetic diversity.

Island Biogeography

The concept that islands closer to a mainland or larger islands will have higher biodiversity.

Endemic species

A species that is native to a specific geographic area and found nowhere else.

HIPPO

An acronym for causes of extinction: Habitat destruction, Invasive species, Pollution, (human) Population, Overharvesting.

Coevolution

Species influence each other’s evolution through close ecological interactions.

Divergent Evolution

Two or more species share a common ancestor but evolve and become less similar over time.

Convergent Evolution

Unrelated species evolve to develop similar traits independently due to similar environmental pressures or ecological niches.