Write short note on Lamarckism.
Write short note on Lamarckism.
- Lamark in his book 'Philosophic Zoologique' ($1809$) proposed that the evolution of life forms had occurred by the use and disuse of organs.
- He gave the example of giraffes, which initially did not have long necks.
- But, due to sudden disappearance of surface vegetation they had to stretch their neck in order to reach the leaves on tall trees.
So they got adapted to this situation by elongation of their necks.
By passing this acquired character to succeeding generation over the years they came to acquire long neck.
This theory also called as Lamarckism is no more accepted now.
- August Weismann offered greatest opposition to his theory of inheritance of acquired characters and put forward this theory of continuity of germplasm in $1892$ .
Similar Questions
Comment on the statement that ''evolution and natural selection are end result or consequence of some other processes but themselves are not processes''.
Comment on the statement that ''evolution and natural selection are end result or consequence of some other processes but themselves are not processes''.
Lamarck's theory of evolution is also called
Lamarck's theory of evolution is also called
Assertion : Human ancestors never used their tails and so the tail expressing gene has disappeared in them.
Reason : Lamarck's theory of evolution is popularly called theory of continuity of germ plasm.
Assertion : Human ancestors never used their tails and so the tail expressing gene has disappeared in them.
Reason : Lamarck's theory of evolution is popularly called theory of continuity of germ plasm.
- [AIIMS 2005]
The scientists believe that evolution is gradual. But extinction, part of evolutionary story, are 'sudden' and 'abrupt' and also group-specific. Comment whether a natural disaster can be the cause for extinction of species.
The scientists believe that evolution is gradual. But extinction, part of evolutionary story, are 'sudden' and 'abrupt' and also group-specific. Comment whether a natural disaster can be the cause for extinction of species.
When we say ''survival of the fittest'', does it mean that $(a)$ those which are fit only survive, or $(b)$ those that survive are called fit ? Comment.
When we say ''survival of the fittest'', does it mean that $(a)$ those which are fit only survive, or $(b)$ those that survive are called fit ? Comment.