Reproductive Isolation

There are two main types of reproductive isolation.

Pre-mating reproductive isolation prevents fertilization from occurring.

• Habitat isolation occurs when the organisms do not encounter each other.
  
  
• Temporal isolation occurs when the organisms mate at different times of the day.
  
  
• Behavioral isolation occurs when the organisms refuse to mate because of different courtship rituals, etc.
  
  
• Mechanical isolation occurs when the male and female genitalia are physically incompatible.
  
  
• Gametic isolation occurs when the male gametes cannot survive in the mating environment long enough to fertilize the female.

Post-mating reproductive isolation prevents the formation of fertile offspring.

• Hybrid inviability occurs when the zygote fails to develop properly and dies.
  
  
• Hybrid sterility occurs when resulting offspring are unable to reproduce as adults.
  
  
• Hybrid breakdown occurs when the hybrids produce offspring that have limited reproductive capacity.