Life on Earth is organised into ecosystems and measured by its biodiversity. This lesson covers types of diversity, how we quantify it with Simpson’s Index, energy flow through ecosystems, and conservation.
You will do two real calculations — a diversity index and an energy-transfer efficiency. Answer the questions and collect ⭐.
Biodiversity is the variety of life. It has three levels:
Species diversity combines richness and evenness. AQA uses Simpson’s Index of Diversity:
D = 1 − ( Σ n(n−1) ) / ( N(N−1) )
where n = number of organisms of one species and N = total number of organisms of all species.
D ranges from 0 to 1; a value closer to 1 means higher diversity.
An ecosystem is a community of organisms plus their abiotic (non-living) environment. Energy enters through producers (photosynthesis) and passes along trophic levels (producer → primary consumer → secondary consumer…).
Only about 10% of the energy at one trophic level is passed to the next; the rest is lost in respiration, movement and as heat. This limits food-chain length.
Conservation protects biodiversity for ecological, economic, aesthetic and ethical reasons.
Sort each item into the correct category.
Match each term to its meaning.
Biodiversity: Genetic, species and habitat diversity
Simpson’s Index: D = 1 − Σn(n−1)/N(N−1); closer to 1 = more diverse
Energy flow: Producers → consumers; roughly 10% passes between levels
Conservation: In situ (habitat) vs ex situ (seed banks, zoos)
Always show your working in index and efficiency calculations. Press Finish.
You've worked through The Living Environment. 🎉
Your stars: 0 / 0
Next: test yourself in the Verify stage.