Evolution and Diversity of Life
What you must know
Evolution by natural selection requires heritable variation within a population, selection pressures that favour some variants, differential survival and reproduction, and inheritance of the favourable alleles, so allele frequencies change over generations. Know the evidence: fossils, comparative anatomy, embryology, molecular and DNA comparisons, and antibiotic resistance as observable evolution in real time. Distinguish homologous structures (same origin, different function) from analogous structures (different origin, similar function), and convergent from divergent evolution. Speciation involves isolation, mutation, selection and, eventually, reproductive isolation.
Classification: binomial nomenclature rules (italicised, genus capitalised, species in lower case), the hierarchical groups, the three-domain and five-kingdom models, and the meaning of the term species. Biodiversity covers variation within species, between species and between ecosystems, together with reasons to conserve it. Expect Lamarck's discredited idea of inheritance of acquired characteristics to appear as a distractor.
Traps and a worked example
Traps: saying an individual evolves or adapts during its lifetime in the evolutionary sense - populations evolve; treating analogous structures as evidence of close relationship; describing antibiotic resistance as bacteria learning; writing binomial names without correct capitalisation or italics.
Worked example: a patient stops antibiotics early. A few bacteria carrying a resistance mutation survive, reproduce, and the population becomes resistant. Rule of thumb: answer with VSSI - Variation, Selection, Survival, Inheritance - and state each step explicitly, because award marks are attached to each stage.