Evolutionary Biology and Speciation

A set of vocabulary flashcards based on lecture notes on population genetics, reproductive isolation mechanisms, and speciation.

Founder Effect

A reduction of genetic diversity in a population that occurs when a new population is formed, resulting in allele frequencies that can be radically different from the mainland population.

Reproductive Isolation

A state in which two populations or species no longer reproduce with each other.

Habitat Isolation

A prezygotic isolation mechanism caused by a physical barrier that prevents two populations from interbreeding.

Prezygotic Barrier

A barrier that prevents fertilization from occurring, helping to avoid wasted reproductive effort.

Temporal Isolation

A reproductive isolation mechanism in which populations are prevented from interbreeding because they reproduce at different times.

Mechanical Isolation

A form of reproductive isolation caused by physical or structural incompatibilities, such as incompatible genitalia or shell spiraling in opposite directions.

Hybrid Breakdown

A postzygotic barrier where first-generation hybrids may be viable, but reproductive failure or breakdown occurs within two to three generations.

Allopatric Speciation

Speciation that occurs when populations are geographically separated by a physical barrier.

Sympatric Speciation

Speciation that occurs without a physical barrier separating individuals in a population.

Adaptive Radiation

An evolutionary pattern driven by niche specialization, where organisms adapt to specific and different parts of the environment.

Assortative Mating

A pattern of sexual selection where individuals choose mates with phenotypes similar to their own (like mates with like).