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Allopatric Speciation

The process of speciation that occurs when populations are geographically isolated, leading to divergence in traits and the formation of new species.

Behavioral Isolation

A type of prezygotic barrier where two populations have differences in mating behaviors, preventing interbreeding.

Biological Species Concept

Defines species as groups of populations that can interbreed and produce fertile offspring but do not breed with other such groups.

Ecological Species Concept

Defines species in terms of their ecological niche, focusing on how they interact with the environment and resources.

Gametic Isolation

A prezygotic barrier where sperm of one species may not fertilize the eggs of another species.

Habitat Isolation

A prezygotic barrier where species occupy different habitats, leading to minimal chances of mating.

Hybrid

The offspring resulting from the interbreeding of two different species.

Hybrid Breakdown

A postzygotic barrier where hybrid offspring are viable and fertile, but their descendants are weak or sterile.

Hybrid Zone

A region where two closely related species meet and interbreed, often resulting in hybrids.

Macroevolution

Large-scale evolutionary changes that occur over long periods, leading to the emergence of new species and higher taxonomic levels.

Mechanical Isolation

A prezygotic barrier resulting from incompatible reproductive structures.

Morphological Species Concept

A definition of species based on structural features and appearance.

Phylogenetic Species Concept

Defines a species based on its evolutionary history and common ancestry, emphasizing genetic similarity and divergence.

Prezygotic Barrier

Any factor that prevents fertilization from occurring between species, such as behavioral or temporal differences.

Postzygotic Barrier

Any mechanism that reduces the viability or reproductive capacity of hybrid offspring after fertilization.

Punctuated Equilibria

A theory suggesting that species remain relatively unchanged for long periods and then undergo rapid changes in short bursts.

Reduced Hybrid Fertility

A postzygotic barrier where hybrid offspring are sterile.

Reduced Hybrid Viability

A postzygotic barrier where hybrid offspring do not develop properly or have lower survival rates.

Reproductive Isolation

Mechanisms that prevent two species from interbreeding and producing viable, fertile offspring.

Speciation

The process through which new species arise due to genetic divergence between populations.

Species

A group of organisms that can interbreed and produce fertile offspring under natural conditions.

Sympatric Speciation

The process of speciation that occurs without geographic isolation, often through mechanisms such as polyploidy or behavioral differences.

Temporal Isolation

A prezygotic barrier where species breed at different times.