Evolution and Classification
What you must understand
Learn natural selection: variation exists, some variants are better adapted, survivors reproduce and pass on alleles, so allele frequencies change over time. Understand evidence for evolution - fossils, homologous structures, DNA similarities, antibiotic resistance. Know speciation and extinction.
Classification groups organisms by shared features: kingdom, phylum, class, order, family, genus, species. Learn the binomial system and the five kingdoms or three-domain approach. Understand why viruses are not classified as living by many biologists.
Traps examiners set
- Saying individuals "adapt" during their lifetime in an evolutionary sense - populations evolve, not individuals.
- Writing binomial names without capitalising the genus and lower-casing the species.
- Confusing classification with identification.
- Claiming evolution is "just a theory" as if it means guesswork.
Worked rule of thumb
For any natural selection question, use the chain: variation → competition → survival of better adapted → reproduction → inheritance → change in frequency. Each link earns a mark.