Biology Exam - Evolution

Adaptation

An inherited trait that increases an organism's chance of survival and reproduction in its environment.

Allopatric speciation

Speciation that occurs when populations are geographically isolated.

Analogous structures

Structures that have similar functions but different evolutionary origins.

Artificial selection

The selective breeding of domesticated plants and animals by humans.

Bottleneck effect

A sharp reduction in the size of a population due to a chance event, reducing genetic variation.

Convergent evolution

The independent evolution of similar traits in different lineages due to similar environmental pressures.

Divergent evolution

The accumulation of differences between groups which can lead to the formation of new species due to isolation.

Evolution

The change in the heritable characteristics of biological populations over successive generations.

Extinction

The complete disappearance of a species from Earth.

Fitness

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

Founder effect

The loss of genetic variation that occurs when a new population is established by a very small number of individuals.

Gene flow

The transfer of genetic variation from one population to another.

Gene pool

The total collection of genes in a population.

Genetic drift

Random changes in allele frequencies within a population, especially in small populations.

Homologous structures

Structures that have a common evolutionary origin but may have different functions.

Macroevolution

Large-scale evolutionary changes, such as the formation of new species and higher taxonomic groups.

Microevolution

Small-scale evolutionary changes within a population, such as changes in allele frequencies.

Molecular evidence

Evidence for evolution based on similarities and differences in DNA, RNA, and proteins.

Mutation

A change in the DNA sequence.

Natural selection

The process by which organisms with advantageous traits are more likely to survive and reproduce.

Reproductive isolation

Mechanisms that prevent interbreeding between different species.

Selective pressure

Environmental factors that influence survival and reproduction.

Sexual selection

A form of natural selection in which individuals with certain traits are more likely to obtain mates.

Speciation

The process by which new species arise.

Stabilizing selection

A type of natural selection that favors intermediate phenotypes.

Disruptive selection

A type of natural selection that favors extreme phenotypes.

Directional selection

A type of natural selection that favors one extreme phenotype.

Survival of the fittest

A phrase describing natural selection, where the 'fittest' are those best adapted to their environment.

Sympatric speciation

Speciation that occurs within the same geographic area.

Vestigial structures

Structures that have lost their original function but are retained in an organism.