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

explain that natural selection occurs because populations have the capacity to produce many offspring that compete for resources; in the ‘struggle for existence’, individuals that are best adapted are most likely to survive to reproduce and pass on their alleles to the next generation

explain that genetic engineering may help to solve the global demand for food by improving the quality and productivity of farmed animals and crop plants, using the examples of GM salmon, herbicide resistance in soybean and insect resistance in cotton