Use of Biological Resources · 6 question types
Past paper frequency (2018 to 2024)
This topic accounts for approximately 9% of your exam marks.
Selective breeding vs natural selection comparisons and examples appear across most papers.
(also called ) is the process by which humans deliberately organisms with desirable characteristics together, over many generations, to produce offspring with those characteristics consistently expressed
Humans have been selectively breeding plants and animals for at least 10 000 years, ever since the first farmers chose which crops to plant from this year's harvest and which animals to keep for next year's breeding. The result is the modern range of crops and farm animals: large, productive, fast-growing, disease-resistant, and almost completely different from their wild ancestors.
The basic procedure is the same for any species:
After enough generations (often tens to hundreds), a new variety has been produced in which every offspring reliably shows the chosen characteristic. This is called a breed in animals, or a or in plants.
Exam note: an answer that only mentions one round of breeding (choose two parents → breed them together → done) is incomplete. The process must be repeated over many generations for offspring to reliably show the desired trait.
The selective-breeding process
Describing selective breeding comes up (2–4 marks), so you need to know the steps: select the individuals that best show the desired characteristic, breed them together, then select the best offspring and breed again, repeating over many generations. A single round of breeding isn't enough — the "repeat over generations" step is its own mark.