Speciation and Extinction

Flashcards covering key vocabulary related to speciation and extinction, including models of speciation, types of extinction, and their causes.

Gradualism

A model of speciation suggesting that evolution proceeds in small, incremental changes.

Punctuated Equilibrium

A model of speciation suggesting that the pace of evolution varies, with short bursts of change in between long periods of little change.

Adaptive Radiation

A phenomenon where a population in a patchy environment gives rise to multiple specialized forms in a relatively short time, often during bursts of speciation.

Background Extinction

The relatively random loss of individual species due to fitness differences like competition, predation, disease, or environmental change, typically offset by speciation.

Mass Extinctions

Significant, non-random departures from background extinction rates, resulting in a substantial loss of taxonomic diversity due to catastrophic events that natural selection does not prepare for.

Impact Theory

A theory suggesting that meteorites or comets caused the extinction of dinosaurs by creating debris that dramatically changed the environment.

Sixth Mass Extinction

The current period of accelerating extinction rates, primarily driven by human activities such as habitat loss, pollution, nonnative species introduction, and overharvesting.