Reproductive isolation barriers: prevent hybridization

HTBMGRRH (How The Beans Might Get Really Really Hot)

Habitat: Temporal: Behavioral: Mechanical: Gametic: Reduced Viability: Reduced Fertility: Hybrid Breakdown

Habitat Isolation

Populations live in different habitats and do not meet

Temporal Isolation

Mating or flowering occurs at different seasons or times of day

Behavioral Isolation

Little or no sexual attraction between males and females

Mechanical Isolation

Structural differences in genitalia or flowers prevent copulation or pollen transfer

Gametic isolation

Female and male gametes fail to attract each other or are inviable

Reduced Hybrid Viability

Hybrid zygotes fail to develop or fail to reach sexual maturity

Reduced Hybrid Fertility

Hybrids fail to produce functional gametes

Hybrid Breakdown

Offspring or hybrids have reduced viability or fertility