Theory:

Darwinpostulates.png
A recall on the postulates of Darwinism
Criticism against Darwinism:
Following are the major factors criticism against Darwinism:
  • All of the variations in organisms may not be a result of adaptation to new demands.
  • Environmental factors are not the only causes of variations. They may be caused even by other factors.
  • The variations which are not useful may also be inherited. Example:Vestigial organs.
  • Darwinism was unable to explain the various reasons for variation as well as the mode of variation transmission.
  • There was no differentiation made between somatic and germ cell variants.
  • Natural selection is an important component, but it is not the only one that contributes to evolution.
  • Small variations in small groups cannot result in speciation.
  • In biological evolution, speciation is a macrophenomenon.
  • Darwinism was unable to account for the most important factors that can lead to speciation.
  • No consideration was given to the genetic basis of inheritance.
Differences between Lamarckism and Darwinism:
S.No
Lamarckism
Darwinism
1.According to this theory there is an internal vital force in all organisms.This theory does not believe in the presence of internal vital force.
2.This theory considers that new needs or desires produce new structures leading to the change in the habits of the organisms.New structures leading to the change in the habits of the organisms is not a part of Darwin's selection theory.
3.
According to this theory if an organism uses a particular organ constantly, the organ would be better developed and the disuse of this organ results in its degeneration.
An organ develops or generates only due to continuous variations.
4.Struggle for existence is not considered here.Struggle for existence plays a prominent role in this theory.
5.According to this theory all the acquired characteristics are inherited to the next generation.According to this theory only useful variations are transferred to the next generation.
6.This theory does not believe in survival of the fittest.Darwin's theory of natural selection in based on the survival of fittest.