AQA · GCSE · Combined Science
Course version: 8464 · Version from Sept 2018
Selective breeding: Selective breeding (artificial selection) is the process by which humans breed plants and animals for particular genetic characteristics. Humans have been doing this for thousands of years since they first bred food crops from wild plants and domesticated animals.
Selective breeding, also called artificial selection, is a human-driven process in which people choose which plants and animals reproduce so that particular genetic characteristics become more…
- 2 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Selective breeding, also called artificial selection, is a human-driven process in which people choose which plants and animals reproduce so that particular genetic characteristics become more common in later generations. Unlike natural selection, the selection pressure is applied by humans rather than by the environment. The chosen parents pass on alleles for the desired features to their offspring, so those features appear more often over time. This has been practised for thousands of years: early farmers saved seed from the best wild plants to grow food crops, and people bred the tamest, most useful domesticated animals. For example, a farmer might breed only cows that produce the most milk, or only wheat plants that give the highest yield. The process changes the allele frequencies in the population and can eventually produce new breeds or varieties.
What earns the marks
- Selective breeding is also known as artificial selection because humans, not the environment, decide which organisms reproduce.
- Humans choose parents that already show a desired genetic characteristic, such as high milk yield in cattle or large grain size in wheat.
- The desired characteristic is controlled by alleles, so selected parents pass those alleles to their offspring.
- Over many generations the proportion of individuals showing the desired characteristic increases in the population.
- The process has been used for thousands of years, beginning with the domestication of wild plants and animals for food.
- Selective breeding differs from natural selection because the selection pressure is applied by humans rather than by environmental factors.
Common mistakes and how to put them right
Thinking that selective breeding creates new alleles.
Put it right: Mutation is the source of new alleles, while selective breeding sorts existing variation.
Confusing selective breeding with genetic engineering.
Put it right: State clearly that no direct gene transfer occurs in selective breeding.
Believing that selective breeding is a modern technology.
Put it right: Link the process to early farming and domestication.
Exam tips
- Define selective breeding in one clear sentence, then give a named example such as dairy cattle or wheat to show understanding.
- Use the phrase 'desired characteristic' and explain that humans choose the parents, so the selection is artificial rather than natural.
- When comparing with natural selection, state that the selection pressure comes from humans in selective breeding but from the environment in natural selection.
Try the lesson
The start of the Selective breeding: Selective breeding (artificial selection) is the process by which humans breed plants and animals for particular genetic characteristics. Humans have been doing this for thousands of years since they first bred food crops from wild plants and domesticated animals. lesson, made from checked teaching notes for this specification point.
Have a go first
Which term describes the process in which humans breed plants and animals for particular genetic characteristics?
Listen
Selective breeding, also called artificial selection, is a human-driven process in which people choose which plants and animals reproduce so that particular genetic characteristics become more common in later generations. Unlike natural selection, the selection pressure is applied by humans rather than by the environment. The chosen parents pass on alleles for the desired features to their offspring, so those features appear more often over time. This has been practised for thousands of years: early farmers saved seed from the best wild plants to grow food crops, and people bred the tamest, most useful domesticated animals. For example, a farmer might breed only cows that produce the most milk, or only wheat plants that give the highest yield. The process changes the allele frequencies in the population and can eventually produce new breeds or varieties. A strong answer earns marks for these points. Selective breeding is also known as artificial selection because humans, not the environment, decide which organisms reproduce. Humans choose parents that already show a desired genetic characteristic, such as high milk yield in cattle or large grain size in wheat. The desired characteristic is controlled by alleles, so selected parents pass those alleles to their offspring. Over many generations the proportion of individuals showing the desired characteristic increases in the population. A common slip: Thinking that selective breeding creates new alleles: it does not; it changes the frequency of existing alleles in the population. Instead, mutation is the source of new alleles, while selective breeding sorts existing variation. Exam tip: Define selective breeding in one clear sentence, then give a named example such as dairy cattle or wheat to show understanding.
See it
Put it in order
Put these steps in the order they happen.
- 1. Humans choose parents showing a desired genetic characteristic
- 2. Selected parents reproduce
- 3. Parents pass alleles for the desired characteristic to offspring
- 4. Desired characteristic appears more often over many generations
- 5. Allele frequencies in the population change
- 6. New breeds or varieties can eventually be produced
- 7. Practised for thousands of years: food crops from wild plants and domesticated animals
Key words
Say what each word means before you turn the card.
Artificial selection
Try answering aloud or in your head before turning the card.
Desired characteristic
Try answering aloud or in your head before turning the card.
See every definition
- Artificial selection
- A human-driven process in which people choose which plants and animals reproduce, also called selective breeding.
- Desired characteristic
- A particular genetic characteristic that humans choose parents to show, so that it becomes more common in later generations.
Label the diagram
Some boxes have lost their names. Pick the right name for each number.
1Box 1
2Box 2
3Box 3
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