Biology Week 7

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Reproductive Isolation: the ability to interbreed. Diverging characters can affect this.

Prezygotic Barriers: A mechanism that blocks reproduction from taking place. Includes barriers that prevent fertilization when organisms attempt to reproduce.

Postzygotic Barriers: Occurs after the zygote (fertilized egg) formation. Includes organisms that don't survive the embryonic stage and those born sterile.

Temporal isolation: Difference in breeding schedules. Can act as a form of reproductive isolation.

Habitat Isolation: Populations of a species move/moved to a new habitat and takes up residence that no longer overlaps with populations of the same species.

Behavioral Isolation: Occurs when the presence/absence of specific behavior prevents reproduction from taking place.

Gametic Barrier: Differences in gamete cells (eggs and sperm) preventing fertilization from taking place.

Hybrid inviability: When fertilization takes place and a zygote forms, postzygotic barriers can prevent reproduction. Hybrid individuals in many cases cant form normally in the womb and dont survive the embryonic stage.

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Species: A group of individual organisms that interbreed and produce fertile, viable offspring. Members of the same species share both external and internal characteristics.

Hybrids: A cross between two species.

Speciation: The formation of two species from one original species.

Allopatric speciation: Involves geographic separation of populations from a parent species and subsequent evolution.

Sympatric Speciation: Involves speciation occuring within a parent species remaining in one location.