You may have seen the new milk ads on TV or at the movies. The animated ads are quite funny, to me at least, and feature prehistoric man being eliminated by dinosaurs. Never mind the questions this brings up. The first ad I saw had a man opening what looks like a pop can and subsequently having the fizz spray him in the eyes. As he staggers about trying to see, other men are running away from something. We then see a dinosaur appear and step on the man. That is when the text appears, "it's always been survival of the fittest." We then see the dinosaur in the distance using a rock to scrape the man off of the bottom of his foot. The only other one I've seen is a still-shot of a dinosaur looking at a tree and all you can see sticking out from behind the tree is a man's big belly. Under this image is the same text as above.
A wise man* once told me that "survival of the fittest" is crap. You can be in the greatest shape imaginable but if something happens to your environment, you're screwed. Consider fish. Consider fish. Hint of the century, consider fish. You could be the fittest fish in the pond/lake. Perhaps, over a few years, there's less and less rainfall each year. Eventually the pond/lake dries up and there is not a drop of water remaining. Survival of the fittest?