Use selective breeding to improve production
Selective breeding uses chosen parents with desirable production traits and selects offspring over repeated generations.
Section 20.1 · Food supply
Core and Extended; Biology 0610, 2026–2028. Use the stated specimen features and evidence. Diagrams are schematic. Written practice is self-checked
Before you begin
- Know that crop and livestock production depend on both management and environmental conditions.
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
What is the key human action in selective breeding?
What you will learn
- Describe selective breeding as a repeated choice-and-breeding process
- Apply it to crop plants and livestock without guaranteeing an outcome
Select parents and repeat across generations
Selective breeding is when humans choose organisms with desirable features as parents. They breed, select offspring that show the desired feature and use selected offspring as parents for later generations. Repeating the process can increase the frequency of useful inherited traits.
For food production, a desired feature might be greater crop yield or a livestock feature such as producing more of a useful product. The syllabus names improving production by crop plants and livestock. A selected trait is not guaranteed in every offspring.
Keep inheritance and conditions in view
Selective breeding is a breeding process across generations. It is not the same as directly changing an organism’s DNA in a laboratory. The offspring inherit combinations of parental information, so results can vary.
Observed production also depends on conditions such as nutrition, disease, water and management. Selection can improve a production trait, but does not guarantee a fixed yield or remove every disadvantage associated with a breeding choice.
Pause and explain
Which sequence best describes selective breeding?
Worked example
A farmer repeatedly breeds crop plants that produce more seeds and selects high-seed offspring as parents. What process is being used?
Show the worked solution
- Humans choose parents for a desired feature.
- The choice is repeated in later generations.
Answer This is selective breeding because people choose parents with a desired production feature and select offspring to breed in following generations.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
Describe how selective breeding could be used to improve crop production over several generations.
Give me a hint
Include chosen parents and offspring selection.
Compare my reasoning
- Choose crop plants with a desired production trait as parents.
- Breed them, select offspring with the trait and use those offspring as parents again.
Select plants with the desired production feature as parents, breed them, select offspring that show the feature and repeat the process over later generations. This can improve production but does not guarantee every offspring has the trait.
Look for these in your work
- Parent selection described
- Repeated offspring selection included
A livestock farmer chooses parents that produce more milk and repeats the choice in later generations. Name the process and one outcome that should not be promised.
Give me a hint
Identify the breeding method and its limit.
Compare my reasoning
- The process is selective breeding.
- Not every offspring is guaranteed to produce more milk.
This is selective breeding. It may improve production in later generations, but it does not guarantee that every offspring will have the desired trait or a particular yield.
Look for these in your work
- Process identified
- Outcome qualified
How is selective breeding different from using a herbicide to increase crop production?
Give me a hint
Compare the mechanism and target.
Compare my reasoning
- Selective breeding chooses parents across generations.
- A herbicide controls weeds and reduces competition.
Selective breeding changes which organisms are chosen as parents across generations. A herbicide controls weeds in a crop field and reduces competition; it does not select crop parents.
Look for these in your work
- Mechanisms separated
- Timescale distinguished
Common mistakes
- Confusing selective breeding with genetic engineering
- Claiming every offspring shows the selected trait
- Ignoring repeated generations
What can you explain now?
What is the key human action in selective breeding?
Compare with the explanation
Choosing parents with desired features
People direct which organisms reproduce.
After trying it yourself, choose your next review. This is your self-assessment.
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Make it stick
Describe the parent-and-offspring steps in selective breeding and explain why it cannot guarantee the same production in every offspring.
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.