GCSE Biology

Inheritance and ecology
revision.

DNA, genetic diagrams, variation, natural selection, ecosystems and human impact.

Inheritance and ecology guides

Pick the idea.
Build the answer.

Jump to a guide

Pick a page.
Not a keyword.

Each box is a full revision page. The smaller line is the search students type — not the name of the guide.

05

Inherited disorders

Apply Punnett squares to GCSE Biology inherited disorders: cystic fibrosis as recessive, polydactyly as dominant, embryo screening, and the ethical arguments mark schemes expect in Combined and Triple.

Open guide
06

Variation and mutation

Separate genetic and environmental variation for GCSE Biology: meiosis, fertilisation, mutation as a DNA change, and why most mutations do nothing while a few change a protein and a phenotype.

Open guide
07

Natural selection

Write natural selection as a sequence for GCSE Biology: variation, competition, survival, reproduction and alleles becoming more common, with antibiotic-resistant bacteria as the example.

Open guide
08

Genetic engineering

Explain genetic engineering for GCSE Biology: cut a gene with restriction enzymes, insert it into a plasmid with ligase, transform bacteria, and evaluate GM crops and insulin without hype or panic.

Open guide
09

Food chains and biomass

Build food chains for GCSE Biology: producer, primary and secondary consumers, pyramids of biomass drawn to scale, and why only about 10% of biomass is passed on at each trophic level.

Open guide
10

The carbon cycle

Track carbon for GCSE Biology: photosynthesis removes CO₂, respiration and combustion return it, decomposition recycles biomass, and fossil-fuel use plus deforestation shift the atmosphere’s balance.

Open guide
11

Biodiversity

Define biodiversity for GCSE Biology as the variety of species, explain why it stabilises ecosystems, and link deforestation, peat destruction, pollution and global warming to specific mechanisms of loss.

Open guide
12

Quadrats and sampling

Plan quadrat and transect sampling for GCSE Biology: random coordinates in a uniform field, a line transect on a gradient, mean scaled to area, and why choosing a “typical patch” is bias.

Open guide
13

Decay and decomposition

Explain decay for GCSE Biology: bacteria and fungi respire dead material, releasing minerals and CO₂ fastest when it is warm, moist and aerobic, and apply that to compost, food storage and the carbon cycle.

Open guide

Keep going

More GCSE Biology
in the same style.

Teacher-written GCSE Biology revision for Combined and Triple Science: cell structure, osmosis, enzymes, photosynthesis, respiration, infection, homeostasis, inheritance and ecology.

All Biology revision