Charles Darwin (1809-1882) was an English naturalist who developed the theory of biological evolution.  Biological evolution states that species develop and change over time through a series small variances that increase the species likelihood of survival and reproduction.  These small variances are passed down from one generation to the next with the variances that give the most competitive advantage expressing itself over time in the species.  Darwin’s theory of evolution is called Darwinism or Darwinian theory.  He published his theory in a 1859 book called Origin of Species.  The evolution of a species is referred to as Phylogenetics.