Read Where Biodiversity Is Greatest
Species richness changes predictably with latitude and elevation; separate the broad pattern from the proposed explanations.
Biodiversity Gradients is the central idea in this question pattern. Identify the condition in the stem before applying the method below.
Follow the gradient
Diversity generally increases toward the equator and lower elevations. Tropical environments receive more solar energy and are often less seasonal; the particular question may ask for only one of these explanatory factors.
Pair diversity with inventory completeness
Tropical regions generally support higher species diversity, while temperate regions have better-completed inventories. Keep the biological pattern separate from sampling completeness: a better catalogue does not mean more species are present.
Read vertebrate-diversity sectors
When a pie chart labels groups only as A–E, first rank the sectors by area, then match the source's group counts to the options. The largest sector in this item is A; the source counts identify A as about 3,000 species and D as about 427.
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- ✓Lower latitude generally supports greater richness.
- ✓Lower altitude generally supports greater richness.
- ✓Read whether the stem asks for a pattern or one cause.
- ✓Tropical regions: higher species diversity.
- ✓Temperate regions: more complete species inventories.
A valid general explanation is not automatically the keyed explanation for a narrowly worded item.
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