Mutational theory of evolution was given by

The correct answer is: Hugo de Vries

Mutation Theory of Evolution
Mutation theory was given by Hugo de Vries in 1901.
According to this theory
(i) Mutations or discontinuous variations are the raw materials of evolution
(ii) Mutations appears all of a sudden. They become operational immediately
(iii) Unlike Darwin’s continuous variations or fluctuations, mutations do not revolve around the mean or normal character of the species
(iv) The same type of mutations can appear in a number of individuals of a species
(v) All mutations are inheritable
(vi) Useful mutations are selected by nature. Lethal mutations are eliminated. However, useless and less harmful ones can persist in the progeny
(vii) Accumulation of the variations produce new species. Sometimes a new species is produced from a single mutations
(ix) Evolution is a jerky and discontinuous process