Question

Which of the following is/are incorrect with respect to the basic concepts of Lamarckism?

1. Internal vital forces
2. Natural selection
3. Effect of environment and new needs
4. Use and disuse of organs
5. Struggle for existence

• A. 1 and 4 only
• B. 2 and 5 only
• C. 3, 4 and 5
• D. 1, 2 and 3

Answer 1

The correct option is B 2 and 5 only

Lamarckism was proposed by J. B. Lamarck in which he explained the inheritance of acquired characters. The basic concepts of Lamarckism as follows:

• Internal vital forces: During the lifetime of an organism, new characters are acquired by the organism due to internal vital force, that is the tendency of organs to grow and increase in size, generation after generation naturally.
• Effect of environment and new needs: Continuous environmental changes influence the organism to produce structures suitable for the current environment.
• Use and disuse of organs: An organ used constantly tends to become more developed whereas the disuse of organ results in degeneration.
• Inheritance of acquired characters: The acquired characters, developed by the organisms during their lifetime in response to the environmental changes, are inherited from one generation to another and this process continues. After several generations, the variations are accumulated upto such an extent that they give rise to new species. For example: The long neck of the modern giraffe could be explained by Lamarckism.

Struggle for existence and natural selection are the features of the theory of natural selection. The theory of natural selection was put forward by Darwin.
Therefore, the incorrect statements are 2 and 5 only.