The mutation theory of organic evolution was propounded by?

Gregor Mendel, through his work on pea plants, discovered the fundamental laws of inheritance. 

 Hugo de Vries (1901) put forward a theory of evolution, called mutation theory. 

Jean Baptiste Lamarck believed that traits changed or acquired over an individual's lifetime could be passed down to its offspring.

The Theory of Evolution by natural selection was first formulated in Charles Darwin's book "On the Origin of Species" published in 1859.