Gymnosperms are more susceptible to extinction than others plant groups because of

Options

A. Reduced genetic veriability
B. Small population size
C. Both (1) and (2)
D. None of these

Answer

**Step-by-Step Solution:**

1. **Understanding Gymnosperms**: Gymnosperms are a group of plants that produce naked seeds, which means their seeds are not enclosed in an ovary. They include groups like Ginkgo, Conifers, Cycads, and Gnetophytes.

2. **Current Status of Gymnosperms**: It is noted that over 40% of Gymnosperm species are at high risk of extinction. This is significant when compared to the vast diversity of Angiosperms (flowering plants), which have around 369,000 species.

3. **Factors Contributing to Extinction**:
- **Reduced Genetic Variability**: Gymnosperms have a lower genetic diversity, which makes them more vulnerable to diseases and environmental changes. This reduced variability can be attributed to limited mutation rates, recombination, and gene flow.
- **Small Population Size**: The total number of Gymnosperm species is relatively small (around 1,000 species), which can lead to inbreeding and further decrease genetic diversity.

4. **Analyzing the Options**:
- **Option 1**: Reduced genetic variability - This is a valid reason for their susceptibility to extinction.
- **Option 2**: Small population size - This is also a valid reason.
- **Option 3**: Both 1 and 2 - Since both factors contribute to the risk of extinction, this option is correct.
- **Option 4**: None of these - This option is incorrect as we have identified valid reasons.

5. **Conclusion**: The correct answer is **Option 3: both 1 and 2**. Gymnosperms are more susceptible to extinction due to both reduced genetic variability and small population size.

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