The animals that have populated the earth have changed and evolved since the universe began - the proof is in the dinosaur skeletons. But never before has one of those species completely dominated the planet in such a powerful and dominating way. Yes, we are that species. Population controls and shifts used to be determined by the forces of nature and the environment, and were a part of the natural progression of the planet. But now we must accept the fact that the responsibility for the number and variety of animals largely rests in our hands.