Speciation and Extinction

Flashcards covering key concepts from the lecture on Speciation and Extinction.

Species

A group capable of interbreeding and producing viable, fertile offspring.

Speciation

The formation of new species, resulting in diversity of life forms.

Allopatric Speciation

Speciation occurring when populations are geographically isolated by physical barriers.

Sympatric Speciation

Speciation that occurs when new species evolve from a single ancestral species while inhabiting the same geographic region.

Prezygotic barriers

Factors that prevent mating or fertilization between species.

Postzygotic barriers

Factors that prevent hybrid zygotes from developing into viable, fertile adults.

Habitat isolation

When species live in different areas or occupy different habitats within the same area.

Temporal isolation

When species breed at different times of the day, year, or season.

Behavioral isolation

When unique behavioral patterns and rituals separate species.

Mechanical isolation

When reproductive anatomy of one species does not fit with the anatomy of another species.

Gametic isolation

When proteins on the surface of gametes prevent the egg and sperm from fusing.

Reduced hybrid viability

When the genes of different parent species interact in ways that impair the hybrid’s development or survival.

Reduced hybrid fertility

When a hybrid develops into a healthy adult but is sterile.

Hybrid breakdown

When the hybrid of the first generation is fertile, but their offspring are sterile.

Microevolution

Change in allele frequencies within a single species or population.

Macroevolution

Large evolutionary patterns that occur over significant time spans.

Punctuated equilibrium

Evolution occurring rapidly after a long period of stasis.

Gradualism

Evolution occurring slowly over extended periods of time.

Divergent evolution

When groups with the same common ancestor evolve and accumulate differences.

Convergent evolution

When two different species develop similar traits despite having different ancestors.

Extinction

The termination of a species.