We can fortell little of the future save that the thing that has not been is the thing that shall be. - J.B.S. Haldane

The change from one stable equilibrium to the other may take place as the result of the isolation of a small unrepresentative group of the population, a temporary change in the environment which alters the relative viability of different types, or in several other ways...

An inordinate fondness for beetles.

At Oxford, the young Haldane was frequently asked whether he was related to the "famous John Scott Haldane", his father, and he would answer "That depends on whether you consider identity to be a relationship."