Forms of Isolation and Isolation Mechanisms

Rhodes 4th Quater

gametic incompatibility

Sperm transfer takes place, but the egg is not fertilized.

zygotic mortality

The egg is fertilized, but the zygote does not develop.

hybrid inviability

Hybrid embryos form, but of reduced viability and do not survive to full maturity.

hybrid sterility 

The hybrid is viable and survives, but the resulting adult is sterile.

hybrid breakdown

First or early-generation hybrids are viable and fertile, but further hybrid generations may be inviable or sterile.  Proves to be unsustainable.

ecological isolation

live in different habitats resulting in them never encountering each other

geographical isolation

geographical barriers prevent them from reaching each other.

behavioral isolation

behavioral differences that lead to them not recognizing each other.

temporal isolation

isolated due to timing issues; reproductively viable at different times of day, seasons, etc.

mechanical/chemical Isolation

prevented from mating because their physical or chemical anatomy and physiology