differences between darwin's and de-vries theory?
Charles Robert Darwin gave the theory of Natural Selection, according to which favourable variations are naturally selected and keep on accumulating in organisms. After many generations, it gives rise to a new species. Hugo de Vries gave the Mutation Theory, according to which variations arise spontaneously as mutations and it is these mutations that control evolutionary change and are more important than natural selection. Differences between these theories are as follows:
|Darwin's theory||de Vries' thoery|
|Variations are continuous||Variations are discontinuous and arise as mutation|
|Natural selection is the most important||Mutation is the most important|
|Evolution is a slow process||Evolution is a sudden process that occurs as saltation|
|Variations are directional||Variations are random|
|For example, The population of short necked giraffes was gradually selected in the direction of long neck variation and slowly modern giraffes with long necks came into existence.||For example, Some individuals of the population of short necked giraffes mutated randomly, but those with a long neck had an advantage in feeding thus were selected by nature and lead to modern giraffes|