A-Level Biology: Biodiversity and Classification

Biodiversity and classification questions look descriptive but are marked analytically: can you apply the species concept to awkward cases, read a diversity index, and justify why molecular comparisons beat morphology? This quiz practises exactly those judgements.

The classification questions cover the biological species concept — defined by interbreeding to produce fertile offspring, with its practical limits acknowledged — courtship behaviour tested by its two genuine functions (species recognition and synchronising readiness to mate), the full taxonomic hierarchy ordered from domain to species, and the binomial system's purpose of unambiguous naming.

The phylogenetics questions carry the analytical weight: why classification by evolutionary history outperforms observable features — with convergent evolution as the trap morphology falls into — and a data-interpretation question comparing cytochrome c amino-acid differences across three organisms to infer relatedness, the exact format exam papers use. A follow-up tests why DNA sequences reveal more than protein sequences: silent mutations, invisible at the protein level, still count in DNA.

The biodiversity questions distinguish species richness (a straight count, tested against an abundance-weighted decoy scenario) from an index of diversity, and cover the impact of intensive farming — monoculture and chemical inputs — along with the valid molecular methods for comparing genetic diversity within and between populations.

Every data scenario is embedded in the question itself. The explanations model the compare-and-justify reasoning this section's extended-response questions demand.

• Apply the biological species concept and explain courtship's role in species recognition
• Order the taxonomic hierarchy and use binomial naming correctly
• Infer evolutionary relatedness from molecular comparison data
• Justify DNA-level comparison over protein and morphological comparison
• Distinguish species richness from diversity indices and assess farming's impact

Topic scope follows the biodiversity and classification content of the DfE A level biology subject content as delivered in current exam-board specifications: species and courtship, taxonomy, phylogeny, diversity measures and molecular comparisons.