The concept of "Biological species " was proposed by `:`

Options

A. Darwin
B. Mayr
C. von Bear
D. Linnaeus

Answer

**Step-by-Step Solution:**

1. **Understanding the Concept of Biological Species:**
- The biological species concept defines a species as a group of individuals that can interbreed and produce fertile offspring. This group is reproductively isolated from other groups, meaning they cannot breed with organisms outside their group.

2. **Identifying the Proposer of the Concept:**
- The question asks who proposed the concept of biological species. We need to evaluate the options provided.

3. **Evaluating the Options:**
- **Option A: Darwin**
- Charles Darwin is known for his theory of evolution by natural selection, proposed in 1859. However, he did not propose the biological species concept.
- **Conclusion:** This option is incorrect.

- **Option B: Ernst Mayr**
- Ernst Mayr is credited with formalizing the biological species concept in the 1940s. He emphasized the importance of reproductive isolation in defining species.
- **Conclusion:** This option is correct.

- **Option C: von Baer**
- Karl Ernst von Baer is known for his work in embryology, particularly for discovering the mammalian ovum. He did not propose the biological species concept.
- **Conclusion:** This option is incorrect.

- **Option D: Linnaeus**
- Carl Linnaeus is recognized as the father of taxonomy and developed a system for classifying organisms based on their characteristics. He did not propose the biological species concept.
- **Conclusion:** This option is incorrect.

4. **Final Answer:**
- The correct answer is **Option B: Ernst Mayr**.