What is "balanced polymorphism?

In simple terms, what is the difference between transient polymorphism and balanced polymorphism?

• Simple terms, please. I don't fully understand the dictionary definitions.

• Answer:

  Let's break the terms down. A polymorphism (poly - many, morph - shape or form) is seen when a population of animals or plants has some members that look different in some way. Most jaguars are yellow with black spots but a few are black with blacker spots. Most tigers are orange but a few are white. These are polymorphisms. Now transient of balanced refers to how long the polymorphism exists in the population. Transient is temporary while balanced is stable and ongoing. So a population of zebras may have an albino zebra that reproduces creating a polymorphism of striped and white zebras. If this is maintained for many generations, with a constant portion of the population white, then it has become a balanced polymorphism. But if lions are more readily hunting and killing the white ones (because they lack camouflage) and so the white ones disappear after a few generations, it would be a transient polymorphism.