Which of these was not conceived by Hugo de Vries to explain evolution?

Options

A. Mutations are large and discontinuous changes
B. Mutations are random and discontinuous
C. Mutations are heritable and establish new species
D. A single step large mutation to produce a species can never occur

Answer

To solve the question "Which of these was not conceived by Hugo de Vries to explain evolution?", we need to analyze each of the statements provided in the context of Hugo de Vries's Mutation Theory.

### Step-by-Step Solution:

1. **Understanding Hugo de Vries's Contribution**:
- Hugo de Vries is known for proposing the Mutation Theory of evolution. He conducted experiments primarily on the evening primrose and concluded that new species arise through mutations.

2. **Analyzing the Statements**:
- **Statement 1**: "Mutations are large and discontinuous changes."
- This statement aligns with de Vries's theory, as he believed mutations were significant and could lead to the formation of new species.

- **Statement 2**: "Mutations are random and discontinuous."
- This is also consistent with de Vries's views. He argued that mutations occur randomly and are not gradual.

- **Statement 3**: "Mutations are heritable and establish new species."
- This statement is true as well. De Vries emphasized that mutations could be passed on to the next generation and could lead to the establishment of new species.

- **Statement 4**: "A single-step large mutation to produce a species can never occur."
- This statement contradicts de Vries's theory. He proposed that a single large mutation (saltation) could indeed lead to the formation of a new species.

3. **Conclusion**:
- The statement that was not conceived by Hugo de Vries is **Statement 4**: "A single-step large mutation to produce a species can never occur."

### Final Answer:
The correct answer is **Statement 4**.

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