A level Biology B · Edexcel 9BI0 · Topic 3C
Biodiversity
Key points
- Biodiversity is the variety of life, including genetic diversity, species diversity and habitat diversity.
- Species richness is the number of species in an area; it ignores how many of each there are.
- The index of diversity takes both richness and evenness into account: , where is the total number of organisms and the number of each species. A higher value means greater diversity.
- Genetic diversity within a species can be estimated by the number of alleles or the proportion of polymorphic gene loci.
- Endemic species are found in only one place.
- Sample at random (e.g. with quadrats at random coordinates) and use enough samples to make results representative.
Topic notesPremium
Biodiversity is the variety of life in an area. Measuring it with numbers, rather than just impressions, lets ecologists compare habitats, track change over time and decide where conservation is most needed.
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