Biodiversity refers to the variety and variability of life on earth. We can think about biodiversity at three levels:
- Genetic diversity within a species
- Species diversity in a community
- Ecosystem diversity in an area
Biodiversity can be impacted by a huge number of factors both biotic and abiotic. Look at the diversity pages for different habitats to see the different factors affecting species diversity and ideas for investigation topics.
Calculating biodiversity
Species diversity can be represented by numerical values. Simpson’s diversity index takes into account species richness and species evenness.
- Richness is a measure of the number of different species in a sample.
- Evenness compares the similarity of the population size of each of the species present.
There are different ways of calculating Simpson’s diversity index. Different exam boards will use different formula, make sure that you use the correct one. Regardless of how it is calculated, the higher the score, the more diverse the community is considered to be.
It is important to think about how you use a biodiversity score. It isn’t meaningful to calculate the score once, instead you should calculate the score for multiple habitats or communities and then compare them.