International A Level Biology / Environment and climate change

Evolution: a change in allele frequency revision notes

Edexcel International A Level Biology (YBI11), chapter 16: Environment and climate change, specification point 5.23. Part of the full course.

Watch the video lesson · International A Level Biology past papers

Evolution is a change in the frequency of alleles in a population over generations. Mutation creates new alleles, and natural selection can make some alleles more common when they help organisms survive and reproduce.

More lessons in Environment and climate change

• Energy transfer between trophic levels
• Gross and net primary productivity
• The carbon cycle
• Using the carbon cycle to reduce atmospheric CO₂
• The greenhouse effect and anthropogenic climate change
• Evidence for climate change: CO2 and temperature records
• Evidence for climate change: pollen in peat bogs and dendrochronology
• The climate debate: correlation, causation and who concludes
• Extrapolating data: climate models and their limitations
• How climate change affects plants and animals
• Temperature, enzymes and Q10
• Core practical 12: temperature and the development of organisms
• Allopatric and sympatric speciation