What is so special about tropics that might account for their greater biological diversity?
a. Unlike temperate regions subjected to frequent glaciations in the past, tropical latitudes have remained relatively undisturbed for millions of years and thus, had a long evolutionary time for species diversification.
b. Temperate environments, unlike tropical ones, are less seasonal, relatively more constant and predictable. Such constant environments promote niche specialization and lead to a greater species diversity.
c. There is more solar energy available in the tropics, which contributes to higher productivity, this in turn might contribute indirectly to greater diversity.

Options

A. a only
B. b and c
C. a and c
D. a, b and c

Answer

To answer the question regarding the special characteristics of the tropics that contribute to their greater biological diversity, we will analyze each of the provided statements step by step.

### Step 1: Analyze Statement A
**Statement A**: "Unlike temperate regions subjected to frequent glaciations in the past, tropical latitudes have remained relatively undisturbed for millions of years and thus, had a long evolutionary time for species diversification."

**Analysis**: This statement is true. Tropical regions have indeed experienced fewer disturbances compared to temperate regions, which have undergone significant changes due to glaciation events. The long, stable climatic conditions in the tropics have allowed for continuous evolution and diversification of species over millions of years.

### Step 2: Analyze Statement B
**Statement B**: "Temperate environments, unlike tropical ones, are less seasonal, relatively more constant and predictable. Such constant environments promote niche specialization and lead to a greater species diversity."

**Analysis**: This statement is false. Temperate environments are actually more seasonal and less constant than tropical environments. The seasonal changes in temperate regions can limit the time available for species to diversify, as organisms must adapt to changing conditions. In contrast, the relatively stable conditions in the tropics promote greater biological diversity.

### Step 3: Analyze Statement C
**Statement C**: "There is more solar energy available in the tropics, which contributes to higher productivity; this in turn might contribute indirectly to greater diversity."

**Analysis**: This statement is true. The tropics receive more solar energy due to their proximity to the equator, leading to higher productivity in terms of plant growth. This abundance of resources supports a larger number of species and contributes to greater biological diversity.

### Conclusion
Based on the analyses:
- Statement A is correct.
- Statement B is incorrect.
- Statement C is correct.

Thus, the special characteristics of the tropics that account for their greater biological diversity are primarily due to the long evolutionary time without major disturbances (Statement A) and the availability of more solar energy leading to higher productivity (Statement C).

### Final Answer
The correct options that explain the greater biological diversity in the tropics are **A and C**.

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