Life Sciences Term 3

Mechanisms of reproductive isolation

Besides geographical barriers, other ways of isolating species is through various reproductive strategies.

• Breeding at different times of the year
• e.g. two species of mayflies emerge during different weeks in springtime.

• Species-specific courtship behaviour
• e.g. two similar species of birds have different mating rituals.

• Adaptation to different pollinators
• e.g. two species of orchid have different length nectar tubes and are pollinated by different species of moths.

• Infertile offspring
• e.g. A donkey and horse are mated and produce a viable mule, however, the mule is sterile.

• Prevention of fertilization due to lack of fit between sexual organs. The species will have specialized genitalia for mating and when it is not the correct size, mating will not be possible.
  
• e.g. two different breeds of dogs