Question

Theory of pangenesis was given by
A. Kerens
B. Mendel
C. De Vries
D. Darwin

Answer 1

Hint:
Various theories and studies have been put forward by different workers on different processes of the biological organisms. Many theories or principles that were proposed by the scientific workers were proposed either by observation or carrying out proper investigation. Some theories were rejected due to lack of proper evidence or they failed to perform while some were widely accepted.

Complete Solution:
The biological organism has been the most important subject for investigation by various workers. The life processes as well as the environment are investigated to discover various reasons underlying for the process. The development, growth, heredity, reproduction are used as a study matter to know more about the living world.

The theory of Pangenesis was proposed by Charles Darwin in the nineteenth century. He proposed that there are some types of hereditary links between the parents and their offspring. This heredity link occurs as a result of the presence of some types of unit of inheritance. The units of inheritance are the processes that control the development of characters of offspring to be similar to their parents. As a result of this theory, Darwin coined the word “gemmules”. The gemmules are referred to as hypothesized minute particles of inheritance that are produced by the cells of the body.

The theory suggested that the environment of an organism could work to modify the gemmules to any parts of the body and these modified types of gemmules would accumulate in the reproductive organs of the parents so that it could be passed on to the next generation.

The Pangenesis theory was based on the claim of theory of acquired characteristics, which stated that characteristics acquired by an organism during its life are heritable in nature. However, the theory of pangenesis did not gain much popularity due to the rejection of the theory of acquired characteristics.

Hence, the option D is the correct and appropriate option.

Additional information:
During the nineteenth century, many scientists sought to explain the mechanism as to how the traits or characters are passed from one generation to another. However, most theories were rejected as they lacked experimental support.

Note: The theory of pangenesis was proposed by Darwin to explain the inheritance of traits or characters in living organisms. He was of the opinion that all parts of the parents could contribute to the evolution and development of the offspring. But this theory was rejected as he never had any experimental results to prove the existence of gemmules.