1(b) Variety of living organisms
Pearson Edexcel International GCSE Biology · 4BI1
Paper 1 | Whole paper: Core content, all five topics
The features of the main groups of organisms — plants, animals, fungi, protoctists, bacteria and viruses — and one named example of each.
Specification coverage
Topic 1 The nature and variety of living organisms (b) Variety of living organisms — statements 1.3–1.10
Assessment objectives: AO1, AO2. Suggested learning time: 60 minutes.
Required knowledge
- Features of plants: multicellular, chloroplasts, photosynthesis, cellulose cell walls, store carbohydrate as starch or sucrose
- Features of animals: multicellular, no chloroplasts, no cell walls, usually nervous coordination, store carbohydrate as glycogen
- Features of fungi: not photosynthetic, cell walls of chitin, may be multicellular with hyphae, feed by extracellular secretion of enzymes (saprotrophic nutrition), store carbohydrate as glycogen
- Features of bacteria: microscopic, single-celled, cell wall, cell membrane, cytoplasm and plasmids, no nucleus but a circular chromosome of DNA
- Features of protoctists: microscopic single-celled organisms, some with features like an animal cell and some like a plant cell
- Viruses as particles, not cells, that can only reproduce inside living cells and have no cellular structure
- A named example from each group, and the pathogens named in the specification
Required skills
- Classify an unfamiliar organism from a description of its features
- Explain why viruses are not classed as living organisms
How it is examined
- Multiple-choice and short-answer recall
- Application of the content to an unfamiliar context
- Extended open-response, marked on the quality of a connected explanation
Common mistakes
- Calling bacteria 'plants without leaves'. Bacteria are prokaryotic: no nucleus, no membrane-bound organelles.
- Saying viruses are alive. They cannot carry out the characteristics of living organisms independently.
- Forgetting the carbohydrate stores, which is one of the specification's clearest discriminators between groups.