Who Discovered The Theory Of Evolution?

Theories are not discovered.  Theories are explanations of how or why things happen.  Sometimes the theories are good and sometimes they are not.  Bad or useless theories generally get discarded.  The theory of evolution is mostly creditid to Charles Darwin.  Many people have expanded and refined the theory over the years.  Alfred Wallace presnted almost the same theory at the same time.  I think Julian Huxley added most to it when he published Evolution, the Modern Synthesis which added genetics to the understanding of how life evolves on earth.