explain that biodiversity can be assessed at different levels, including: • the number and range of different ecosystems and habitats • the number of species and their relative abundance • the genetic variation within each species

use the Hardy–Weinberg principle to calculate allele and genotype frequencies in populations and state the conditions when this principle can be applied (the two equations for the Hardy–Weinberg principle will be provided, as shown in the Mathematical requirements)

explain that crossing over and random orientation (independent assortment) of pairs of homologous chromosomes and sister chromatids during meiosis produces genetically different gametes