Glossary

• Hardy-Weinberg principle = a mathematical equation that calculates the frequency of alleles and phenotypes/genotypes
• Mutations = permanent changes in DNA sequence, creating genetic variation
• Normal distribution curve = bell-shaped graph showing continuous variation where most individuals have intermediate traits
• Sectional pressures = environmental factors affecting survival and reproduction, driving natural selection
• Gene pool = total collection of alleles in a population
• Intraspecific competition = competition between individuals of the same species for resources
• Stabilising selection = selection that favours average traits and reduces variation
• Directional selection = selection that favours both extremes, leading to potential speciation
• Allelic frequency = proportion of a specific allele in a population's gene pool
• Speciation = formation of new species due to reproductive isolation and genetic divergence
• Reproductively separate = when populations can no longer interbreed successfully
• Adaptive radiation = rapid evolution of multiple species from a common ancestor to exploit different niches
• Genetic drift = random changes in allele frequencies, affecting small populations
• Allopatric speciation = speciation due to geographic isolation preventing gene flow
• Sympatric speciation = speciation without geographic separation often due to ecological or behavioural differences
• Geographically separated = when populations are physically divided by barriers like mountains or rivers