Name: Formation of New Species
Uploaded: 2019-07-19
Duration: 7 min 8 s
Description: New species are formed when their members are no longer able to reproduce with members of the parent species. See how new species are formed in this video.

Question

Write the objections to Mutation theory of Hugo de Vries.

Accepted Answer

The main features of mutation theory given by H. de Vries are:

Mutations are large, sudden and discontinuous variations in a population.

These changes are inheritable.

Mutations provide the raw material for organic evolution.

Mutation may be useful or harmful. Useful mutations are selected by nature.

Mutations are nondirectional, forward or backward.

Accumulation of these mutations over a period of time leads to the origin and establishment of new species.

Harmful mutation may persist or get eliminated by nature.

Speciation may take place by saltation.

The major objections of this theory are:

The rate of mutation in nature is much slower compared to the requirement of evolution.

The large and discontinuous variations observed by Hugo de Vries were actually due to chromosomal aberrations and not gene mutation.

Chromosomal aberrations are unstable and thus, has less significance in the process of evolution.

Gene mutation play least significance in evolution.

The non-directional property of mutation cannot be considered in evolution which always show progressing increase in complexity.

Mutation theory cannot satisfactorily explain the development of mimicry, mutual dependence of flowers and pollinating insects.

	Column I		Column II
1	August Weissman	P	Mutation theory
2	Hugo de Vries	Q	Germplasm theory
3	Charles Darwin	R	Theory of acquired characters
4	Lamarck	S	Theory of natural selection

Write the objections to Mutation theory of Hugo de Vries.

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