Freshman Year Biology - Unit 13: Evolution

Evolution

Biological change in populations over time.

Microevolution

Small-scale evolution affecting a single population.

Macroevolution

Large-scale evolution affecting species across populations.

Natural Selection

Process where organisms with favorable traits survive.

Fitness

Ability to survive and reproduce in an environment.

Descent with Modification

Species change over time from common ancestors.

Gene Pool

All alleles of all genes in a population.

Genetic Drift

Change in gene frequency due to chance events.

Founder Effect

Genetic drift occurring when a new population is established.

Bottleneck Effect

Genetic drift due to a significant reduction in population size.

Artificial Selection

Humans select organisms for desirable traits.

Directional Selection

Favors one extreme phenotype over others.

Stabilizing Selection

Eliminates extreme phenotypes, reducing variation.

Disruptive Selection

Favors extreme phenotypes, selects against average.

Behavioral Isolation

Populations cannot mate due to behavioral differences.

Temporal Isolation

Species reproduce at different times.

Geographic Isolation

Physical separation of populations by barriers.

Mechanical Isolation

Physical differences prevent fertilization between species.

Punctuated Equilibrium

Evolution marked by rapid speciation and long stasis.

Convergent Evolution

Unrelated species evolve similar traits.

Divergent Evolution

Closely related species evolve different traits.

Coevolution

Species evolve in response to each other.

Adaptive Radiation

Single species evolves into diverse forms.

Mass Extinctions

Widespread and rapid decrease in biodiversity.

Background Extinctions

Continuous low-rate species elimination due to environmental changes.

Anatomical Evidence

Structures that indicate evolutionary relationships.

Homologous Structures

Similar structures in different species from common ancestry.

Analogous Structures

Similar functions in different species, not from common ancestry.

Vestigial Structures

Non-functional structures that were useful in ancestors.

Embryological Development

Similarities in early development across species.

Molecular Clues

DNA and protein similarities indicating evolutionary relationships.