Chapter 9 / 5 short lessons
Variation, selection and species
Explain changes across generations by linking inherited variation to reproductive success, then test what the evidence can establish.
H1 Biology / 8876 / 2027 syllabus
What do you think?
An antibiotic is applied to a bacterial population. Must it create the exact resistance mutation that the bacteria need?
Lessons
0 of 5 marked as readSupply the variation selection needs
Explain why heritable variation from mutation, meiosis and sexual reproduction is needed for natural selection.
About 5 minExplain why an environment favours a variant
Use environmental examples to explain differential survival and reproduction.
About 5 minRead a change across generations
Explain evolution through natural selection and distinguish a population change from evidence for its cause.
About 5 minExplain why harmful alleles can persist
Explain preservation of genetic variation, including masking of recessive alleles and context-dependent heterozygote advantage.
About 5 minDecide what makes a biological species
Explain the biological species concept and apply its reproductive criterion with appropriate limits.
About 5 minWhat you will be able to do
- Explain where heritable variation comes from.
- Build a complete natural-selection explanation.
- Explain persistent variation and the biological species concept.
Spaced review
Remember this chapter
Save this chapter's 15 recall cards. We'll bring each one back just before you're likely to forget it, a few minutes a day.
Free account needed, so your cards follow you to any device. Notes and quick recall stay free without one.