Darwin in his 'Natural Selection Theory' did not believe in any role of which one of the following in organic evolution

Options

A. Parasites and predators as natural enemies
B. Survival of the fittest
C. Struggle for existence
D. Discontinuous variations.

Answer

**Step-by-Step Text Solution:**

1. **Understanding Darwin's Theory of Natural Selection**:
- Darwin's theory of natural selection emphasizes the process by which organisms better adapted to their environment tend to survive and produce more offspring. This process is often summarized by the phrase "survival of the fittest."

2. **Identifying the Options**:
- The question provides several options:
- A) Parasites and predators as natural enemies
- B) Survival of the fittest
- C) Struggle for existence
- D) Discontinuous variation

3. **Analyzing Each Option**:
- **A) Parasites and predators as natural enemies**: Darwin acknowledged that these factors play a role in natural selection by influencing survival rates.
- **B) Survival of the fittest**: This is a key concept in Darwin's theory, indicating that only the organisms best suited to their environment will survive and reproduce.
- **C) Struggle for existence**: This concept is central to Darwin's theory, referring to the competition among organisms for limited resources.
- **D) Discontinuous variation**: Darwin did not believe that discontinuous variation (sudden, distinct changes) played a significant role in evolution. He supported the idea of gradual, continuous variation.

4. **Conclusion**:
- Based on the analysis, the option that Darwin did not believe played a role in organic evolution is **D) Discontinuous variation**.

**Final Answer**: D) Discontinuous variation

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