Agriculture and evaluating biotechnology — Edexcel GCSE Biology
Fertilisers and biological control for a growing population, and the benefits and risks of genetic engineering and selective breeding.
Revision notes
2 short notes, in the order of the specification. Each one in short:
Fertilisers and biological control are agricultural solutions for feeding a growing human population. Fertilisers add mineral ions such as nitrates to the soil, increasing crop yield, but they can wash into rivers and pollute water. Biological control uses living organisms, such as ladybirds that eat aphids, to control pests without chemicals, but it is slower than pesticides.
Evaluating genetic engineering and selective breeding means weighing up their benefits and risks, including practical and ethical implications, then reaching a judgement. Selective breeding raises yields but takes many generations and reduces genetic variation. Genetic engineering is quicker and can produce medicines such as human insulin, but it has unknown effects and raises ethical concerns.
Exam questions
4 exam-style questions (14 marks), each with its mark scheme.
Answer the questionsFlashcards
9 cards: flip them, mark what you knew, and practise the rest.
Practise the cardsMind map
The whole of natural selection and genetic modification on one page, so you can see where this subtopic fits.
Open the mind mapPrint it
Free PDFs to print or save.
Quick check questions
What does 'evaluate' require you to do in a question about genetic engineering?
Show answer
Weigh up benefits and risks, including practical and ethical implications, and reach a judgement.
Name one practical and one ethical implication of genetic engineering.
Show answer
Practical: it is costly or may not work. Ethical: some think it is wrong to alter the genes of organisms.
Give one risk of selective breeding.
Show answer
It reduces genetic variation, or inbreeding causes health problems.
Frequently asked questions
What are the advantages and disadvantages of biological control?
Triple only Biological control uses living organisms, such as ladybirds that eat aphids, to control pests. It leaves no chemical residues on food, usually targets only the pest and can keep working for a long time. However, it is slower than pesticides, may not remove the pest completely, and the control organism could become a pest itself.
Why do farmers use fertilisers?
Triple only Farmers use fertilisers to add mineral ions, such as nitrates, to the soil. Plants need these ions to grow well, so crop yields increase and more food is produced from the same land. However, fertilisers cost money and can be washed off fields into rivers and lakes, polluting water and harming wildlife.
What are the ethical issues with genetic engineering?
The ethical issues with genetic engineering are about what people think is right or wrong. Some people think it is wrong or unnatural to change the genes of living things, especially animals, and there are concerns about animal welfare. Alongside these, there are risks such as unknown effects on the environment and human health.
Is genetic engineering better than selective breeding?
Neither is better in every case, so you must weigh them up. Genetic engineering is quicker and can add new characteristics, such as insect resistance, or make medicines like human insulin, but it may have unknown effects. Selective breeding needs no special equipment but takes many generations, reduces genetic variation and can cause inbreeding problems.
Written and checked against the Edexcel GCSE Biology (1BI0) specification · Updated October 2026