Habitat isolation

A prezygotic barrier;

geographic barrier prevents contact

Temporal isolation

Prezygotic barrier;

species reproduce at different times of

the day or year

Behavioral isolation

Prezygotic barrier;

since behavior is important in mate choice, differing patterns prevents mating between species

(Ex: different bird songs)

Mechanical isolation

Prezygotic barrier;

size or incompatible genitalia prevents mating

(physically incompatible)

Gametic isolation

Prezygotic barrier;

gametes fail to unite succesfully

(otherwise compatible, but sperm doesn't fuse with egg)