The main drawback of Darwin's theory of natural selection was that it could not provide satisfactory explanation of

Options

A. Survival of fittest
B. Struggle for existence
C. Mimicry
D. Basis of variation and the mode of transmission of the variants to the next generation.

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the main drawback of Darwin's theory of natural selection. This requires us to identify a specific aspect of his theory that was not adequately explained.

2. **Identifying the Drawback**: The main drawback of Darwin's theory is that it could not satisfactorily explain the concept of discontinuous variations. Discontinuous variations refer to traits that do not show a range but rather fall into distinct categories (e.g., tall vs. short).

3. **Explaining the Lack of Explanation**: Darwin's theory did not adequately address how these discontinuous variations were passed on from one generation to the next. This is crucial because understanding the mechanism of inheritance is essential for the theory of natural selection to be complete.

4. **Darwin's Attempt to Address This**: In 1868, Darwin proposed a theory called Pangenesis. He suggested that every organ of the body produces tiny hereditary particles called pangenes or gammules, which are carried through the blood to the gametes (sperm and egg cells).

5. **Critique of Pangenesis**: Although Darwin attempted to explain the transmission of variations through Pangenesis, this theory was not satisfactory or widely accepted. It lacked empirical support and did not clarify how traits were inherited.

6. **Conclusion**: Therefore, the main drawback of Darwin's theory of natural selection is its inability to explain the basis of variation and the mode of transmission of these variations to the next generation.

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