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EnglandBiology

Module 4: Biodiversity, evolution and disease

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How is biodiversity measured and sampled, and why does maintaining it matter?

4.2.1 Biodiversity: the levels of biodiversity (habitat, species and genetic); how to sample plants and animals (random sampling, quadrats, transects and mark-release-recapture); the calculation and interpretation of Simpson's index of diversity; and the ecological, economic and aesthetic reasons for maintaining biodiversity.
A focused answer to the OCR H420 4.2.1 dot point on biodiversity. Covers habitat, species and genetic diversity, sampling methods including quadrats, transects and mark-release-recapture, the calculation and interpretation of Simpson's index of diversity, and the reasons for maintaining biodiversity.
13 min answer →

How are organisms classified, and how does molecular evidence reveal their evolutionary relationships?

4.2.2 Classification and evolutionary relationships: the binomial system and the taxonomic hierarchy; the five kingdoms and the three-domain classification; the meaning of phylogeny; and how molecular evidence (DNA base sequences, amino acid sequences) and other evidence are used to clarify evolutionary relationships.
A focused answer to the OCR H420 4.2.2 dot point on classification. Covers the binomial system and taxonomic hierarchy, the five kingdoms and the three-domain system, the meaning of phylogeny, and how molecular and other evidence is used to establish evolutionary relationships.
12 min answer →

What causes communicable diseases, how do they spread, and how do plants and the body's non-specific defences resist them?

4.1.1 Communicable diseases: the range of pathogens (bacteria, viruses, fungi and protoctists) and the communicable diseases they cause in animals and plants; the means of transmission; the primary non-specific defences of plants and animals; and the role of phagocytes in the non-specific immune response.
A focused answer to the OCR H420 4.1.1 dot point on communicable diseases. Covers the four pathogen groups and example diseases, means of transmission, the primary non-specific defences of plants and animals, and the role of phagocytes in non-specific immunity.
12 min answer →

How does natural selection change populations over time, and what evidence supports evolution?

4.2.2 Evolution: the process of evolution by natural selection acting on variation; the role of mutation in generating variation; the types of natural selection (directional, stabilising and disruptive); the evidence for evolution from fossils, comparative anatomy and molecular biology; and examples such as antibiotic resistance and industrial melanism.
A focused answer to the OCR H420 4.2.2 dot point on evolution. Covers natural selection acting on variation, mutation as the source of variation, directional, stabilising and disruptive selection, the evidence for evolution, and examples such as antibiotic resistance and peppered moths.
12 min answer →

How does the specific immune response work, how does vaccination give immunity, and why are antibiotics losing their power?

4.1.1 The immune response: the structure and function of antibodies; the roles of B and T lymphocytes in the humoral and cell-mediated responses; the primary and secondary responses and the role of memory cells; the principles of vaccination and herd immunity; the differences between active, passive, natural and artificial immunity; and the development of antibiotic resistance.
A focused answer to the OCR H420 4.1.1 dot point on the specific immune response. Covers antibody structure, B and T lymphocytes, the primary and secondary responses, memory cells, vaccination and herd immunity, the four types of immunity, and how antibiotic resistance evolves.
14 min answer →