Speciation and Macroevolution

These flashcards cover key concepts related to speciation, reproductive isolation, and evolutionary theory, serving as study aids for reviewing the content presented in the lecture.

Speciation

The origin of new species; a focal point of evolutionary theory.

Biological Species Concept

Defines a species based on the ability to interbreed and produce viable, fertile offspring.

Reproductive Isolation

Barriers that prevent different species from producing viable, fertile offspring.

Prezygotic Barriers

Prevent fertilization from occurring, including habitat, temporal, behavioral, mechanical, and gametic isolation.

Postzygotic Barriers

Prevent hybrid zygotes from developing into viable, fertile adults; includes reduced hybrid viability, fertility, and hybrid breakdown.

Allopatric Speciation

Speciation that occurs when a population is geographically isolated, interrupting gene flow.

Sympatric Speciation

Speciation that occurs in overlapping populations without physical barriers, often due to habitat differentiation or sexual selection.

Polyploidy

Condition of having extra sets of chromosomes, often leading to speciation, especially in plants.

Morphological Species Concept

Defines a species by structural features; applies to both sexual and asexual species.

Ecological Species Concept

Defines a species in terms of its ecological niche and role within its environment.

Hybrid Zones

Regions where members of different species mate and produce hybrids; can result in reinforcement, weakening, or continued formation of hybrids.

Punctuated Equilibrium

Model suggesting that species experience long periods of stasis interrupted by short bursts of rapid change.