9700 · 18.2
Biodiversity flashcards
Revision flashcards for Cambridge 9700 Biodiversity (syllabus 18.2). Flip, recall, then mark a real past-paper question.
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What are the three levels of biodiversity?
1. **Species diversity:** Variety of species. 2. **Genetic diversity:** Variety of genes/alleles within a species. 3. **Ecosystem diversity:** Variety of habitats and communities.
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What are the two components of species diversity?
**Species richness** (the number of different species) and **species evenness** (the relative abundance of individuals of each species).
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What is genetic diversity and why is it important?
It is the variety of genes and alleles within a species. It is crucial for adaptation to environmental changes (e.g., new diseases, climate change) through natural selection.
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What is endemism?
A state where a species is unique to a single defined geographic location, such as an island or nation, and is found nowhere else in the world.
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What are the two criteria for a region to be classified as a biodiversity hotspot?
1. It must contain at least 1,500 species of vascular plants as endemics (>0.5% of the world's total). 2. It must have lost at least 70% of its original natural vegetation.
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What does Simpson's Index of Diversity (D) measure?
It measures the biodiversity of a habitat, taking into account both species richness and species evenness.
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What does a Simpson's Index of Diversity (D) value close to 1 indicate?
A value close to 1 indicates a high level of biodiversity. The ecosystem is likely to be stable, with high species richness and evenness.
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What does a Simpson's Index of Diversity (D) value close to 0 indicate?
A value close to 0 indicates a low level of biodiversity. The habitat is likely dominated by one or a few species and is less stable.