| Front | What are nitrogen fixing bacteria? |
| Back | They transform atmospheric nitrogen into fixed nitrogen. Plants then take up the nitrogen as nitrates. |
| Tags | U3T1 |
| Front | How does species diversity differ from species richness? |
| Back | A measure of the number of species found in a community, compared with the number of individuals (relevant to Simpson's diversity index). It differs from species richness as it takes into account both the numbers of species and the evenness of species in relation to one another - relative abundance |
| Tags | U3T1 |
| Front | In terms of population growth what are density independent factors? |
| Back | Density-independent factors- Abiotic factors in the environment that affect populations regardless of their density e.g. temperature, storms, habitat destruction, drought Density-independent factors affect all populations in similar ways, regardless of the population size. |
| Tags | U3T2 |