Natural Selection and Evolution

Flashcards covering key concepts and vocabulary related to natural selection and evolution.

Natural Selection

The process where organisms with favorable traits survive and reproduce, passing those traits to the next generation.

Variation

Differences among individuals in a population.

Competition

Struggle for resources among individuals in a population.

Adaptation

Changes in traits that enhance survival and reproduction in a specific environment.

Descent with modification

The process by which descendants of ancestral species evolve adaptations to diverse environments.

Fossils

Remains or traces of organisms from the past that provide evidence of change over time.

Homologous structures

Structures that are similar in different species due to common ancestry but may serve different functions.

Analogous structures

Structures in different species that perform similar functions but do not share a common ancestry.

Vestigial structures

Body parts that have lost their original function through evolution (e.g., appendix in humans).

DNA evidence

The most reliable method for determining relatedness among species.

Stabilizing selection

A type of selection where the average phenotype is favored and extremes are selected against.

Directional selection

A type of selection that favors one extreme phenotype over others.

Disruptive selection

A type of selection that favors both extreme phenotypes and selects against the average phenotype.

Divergent evolution

Evolution where related species develop different traits due to different environments.

Convergent evolution

Evolution where unrelated species develop similar traits due to similar environmental pressures.

Speciation

The process by which new species arise due to reproductive isolation.

Geographic isolation

Isolation that occurs when populations are separated by physical barriers.

Behavioral isolation

Isolation resulting from differences in mating behaviors.

Reproductive isolation

A condition in which two populations cannot mate successfully.

Allele frequency

The relative frequency of an allele at a genetic locus in a population.

Genetic drift

Random changes in allele frequencies that occur in small populations.

Hardy-Weinberg Equilibrium

A principle that describes a population that is not evolving, maintained under specific conditions.

Evolutionary conditions for Hardy-Weinberg

No mutation, no migration, large population, random mating, no natural selection.