individuals in a population show genetic variation because of differences in their alleles and new alleles arise through mutations
things like predation, competition and diseases can act as selection pressures meaning it can affect an organisms chance of surviving and reproducing
organisms with characteristics that make them better adapted to the selection pressures have a better chance of survival
what is Darwin's theory of evolution?
natural selection
what are the key ideas of natural selection?
organisms show genetic variation due to random mutation - best adapted to survival and reproduce - best adapted pass on beneficial alleles to offspring