AP BIO Evolution

Genetic Drift

Random changes in allele frequencies in a population.

Founder Effect

When a small group starts a new population, leading to reduced genetic diversity.

Adaptive Radiation

A single species evolves into many different forms to fill various niches.

Evolution

The change in species over time due to genetic variation and selection.

Natural Selection

Organisms with beneficial traits survive and reproduce more.

Disruptive Selection

Extreme traits are favored over the average trait.

Directional Selection

One extreme trait is favored over others.

Stabilizing Selection

The average trait is favored, while extremes are selected against.

Convergent Evolution

Unrelated species develop similar traits due to similar environments.

Divergent Evolution

A common ancestor leads to species that become more different over time.

Homologous Structures

Similar structures in different species due to a common ancestor.

Analogous Structures

Different structures with similar functions, not due to a common ancestor.

Vestigial Structures

Body parts that have lost their original function.

Fossils

Preserved remains of ancient organisms.

Biogeography

The study of where species live and how they evolved.

Embryology

The study of embryos to understand evolutionary relationships.

Gene Flow

The movement of genes between populations.

Fitness

How well an organism survives and reproduces.

Allopatric Speciation

New species form due to geographic separation.

Sympatric Speciation

New species form without geographic separation.

Reproductive Isolation

When species can’t mate due to barriers like behavior or genetics.

Punctuated Equilibrium

Evolution happens in quick bursts, not gradually.

Gradualism

Evolution happens slowly over time.

Heterozygous Advantage

When being heterozygous for a gene gives a survival advantage.

Stickleback Evolution

Stickleback fish lost spines and armor in freshwater populations due to less predation.

Hardy-Weinberg Problems

Mathematical equations to calculate genotypic frequencies in populations.

Amniote Eggs

Came before hair in evolutionary history.

Keratinized Skin

Came before bipedalism in evolutionary development.

Jawless Animal

Hagfish or lamprey.

Animals with Lungs

Amphibians, reptiles, birds, and mammals.

Common Ancestor of Pigeon, Mouse, and Chimp

A reptile-like ancestor.

Outgroup Organism

The species that shares the least traits with the rest in a cladogram.