There is plenty of "proof" of evolution. There are very few branches of biology in which it is possible to work without taking evolution into account.
The reason I put "proof" into quotes is that, in science, nothing is ever really "proven". The best we can do is to gather more evidence; either the evidence supports the theory or it doesn't.
In the case of evolution, the evidence supporting the theory is overwhelming. That isn't to say that the theory cannot undergo revision as more evidence is accumulated; such revision is an integral part of science. When evidence just plain does not support a theory, the theory is rejected in favor of a better one--that is why we look to Charles Darwin as an early pioneer in biology, and not Jean-Baptiste Lamarck. Darwin's theory best fit the data; Lamarck's did not.