Why do animals evolve?
Evolution has produced all the creatures found on Earth. The evidence for this comes from fossils, and from comparing the structure and chemistry of living creatures. But what makes evolution happen? Scientists believe that the answer is something called 'natural selection'. All animals and plants produce more young than can possibly survive. Some die, while others go on to produce young of their own. In general, the one that are best suited to their environment survive, while the weakest die out. Because the best adapted survive and are most likely to pass on their genes to the next generation, the species gradually becomes more suited to its environment.