Biodiversity Notes

Biodiversity is the variety of life, including variability within species, between species, and of ecosystems.
Biodiversity hotspots are regions with significant reservoirs of biodiversity that are under threat from humans.
Building blocks:
- Genetic diversity: Variation in genes and nucleotides.
- Organismal diversity: Includes individuals, populations, subspecies and species.
- Ecological diversity: includes habitats, ecosystems, biomes.

Species richness: The number of species per unit area.
Limitations of species richness:
- Not all species are equal (common vs rare).
- All taxa cannot be surveyed.
- Different sampling techniques.
- Species ID is often difficult.
Species: Members who breed mostly amongst themselves, making them reproductively isolated and genetically distinct from others.
There are approximately 2.13 million named species.
Evenness: measure how similar different species are in abundance
Indices of Diversity
- Shannon-Wiener Index: $H' = -∑ pi (ln (pi))$ where $p<em>i$ = the proportion of individuals from species i and $ln(p</em>i)$ = the natural log of pi
- Simpson Index: $D = ∑ (pi)^2$ (probability that any two species picked at random will be the same species) where $p_i$ = the proportion of individuals from species i. Usually expressed as $1-D$ or $1/D$ .

Ecosystem Services:
- Provisioning: Food, fibre, fuel, genetic resources, biochemicals, freshwater.
- Regulating: Air quality, climate, water purification, disease, pollination.
- Supporting: Soil formation, photosynthesis, nutrient cycling.
Utilitarian Value: Monetary value of ecosystems and species.
Heritage Value: National Identity.
Existence and Ethical Value: Biodiversity should be conserved for its ‘existence’ value.
Current extinction rate is greater than historical rate.