As has been touched on here before, others have given quite some thought to the regulatory processes of good ol' Mother Nature.

"Now University of Washington paleontologist Peter Ward has proposed an alternate theory that suggests Earth is set up to kill off life when it spreads too widely. Humans wouldn't be the first victims of this periodic biocide. The dinosaurs may have been killed off by an asteroid, he says, but during the planet's other mass extinctions, millions of species were done in by good old Mom.

"I hypothesize that life and its processes, together often referred to as 'Mother Nature,' was, is, and will be anything but a good mother to her many evolved and evolving species," Ward contends in his new book, "The Medea Hypothesis."