Assess biodiversity at genetic, species and ecosystem levels by interpreting sampling data and comparing variation within and between groups in Cambridge A Level Biology questions.
Biodiversity can be assessed at three different levels. One of these is the genetic variation within each species.
Outline two other levels at which biodiversity can be measured.
To calculate the genetic variation that exists within a species, scientists:
- obtain DNA sequences from many individuals of one species
- count the number of nucleotides that differ when the sequences of two individuals are compared
- repeat this with different pairs of individuals.
This allows scientists to calculate the mean number of differences at every nucleotide position along the sequence (mean number of nucleotide differences per site).
1 number of / range of (different), ecosystems / habitats ;
2 number of species and their relative abundance ;