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LearnEdexcel4BI12017 specificationPaper 1B · Paper 1 (core content)The nature and variety of living organisms
Paper 1B · Module

The nature and variety of living organisms

2 subtopics≈ 65 min in total
Start the module: Characteristics and classificationOpen graphing calculator

  1. Characteristics and classification

    All living things show seven characteristics: Movement, Respiration, Sensitivity, Growth, Reproduction, Excretion, Nutrition (MRS GREN). Organisms are classified into groups by shared features, from kingdom down to species. The binomial system gives each species a two-part Latin name: genus then species, e.g. Homo sapiens. A dichotomous key identifies an organism through a series of two-way choices.

    ≈ 35 min

  2. Microorganisms and viruses

    Fungi (e.g. yeast, Mucor) have a chitin cell wall, feed by saprotrophic nutrition (secreting enzymes onto food), and many grow as thread-like hyphae forming a mycelium. Bacteria (prokaryotes) are single cells with no nucleus. Protoctists are mostly single-celled with a nucleus; some are animal-like (Amoeba), some plant-like (Chlorella), some cause disease (Plasmodium, malaria). Viruses are not cells: just genetic material in a protein coat, and they reproduce only inside living cells.

    ≈ 30 min