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:
|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.|
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.|