Of the two pink monkeys in the world – one male, one female – the female dies, ensuring that there will never be a pure-bred pink monkey again.
A random succession of births results in all other hair colors going extinct within a village full of redheaded people.
The freckled dazzle-flower exchanges genetic material with a small population of un-freckled dazzle-flowers. After a few seasons, there are no un-freckled dazzle-flowers left.