Key Concepts in Evolution and Natural Selection

Variation

Differences in traits (like size, color, or behavior) within a population of the same species.

Reproduction

The process by which organisms produce offspring, passing on genetic information.

Directional Selection

A type of natural selection where one extreme trait is favored, shifting the population in that direction.

Extinction

When all members of a species die out and the species no longer exists.

Derived Characteristic

A trait that evolved in the most recent common ancestor and is shared by its descendants, used in cladistics.

Generation

A group of individuals born and living around the same time; the time between the birth of parents and their offspring.

Outgroup

A species or group that diverged before the group of interest in a cladogram; used for comparison.

Taxonomy

The science of classifying and naming organisms based on shared traits.

Population

A group of organisms of the same species living in the same area at the same time.

Carrying Capacity

The maximum number of individuals an environment can support without running out of resources.

Descent with Modification

The passing of traits from parents to offspring with changes over generations, leading to evolution.

Selective Pressure

An environmental factor (like predators, climate, or food availability) that affects an organism's survival and reproduction.

Binomial Nomenclature

A system that gives each organism a two-part scientific name (Genus species), developed by Linnaeus.

Sexual Selection

A form of natural selection where individuals with traits that increase mating success are more likely to reproduce.