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Selective Breeding
Selective Breeding Revision
Selective Breeding
Selective breeding is where humans breed certain individuals together to create offspring with desired traits. It has many benefits to humans but it reduces the gene pool of the species selected which causes many issues.
What is Selective breeding?
Selective breeding, also known as artificial selection, is when humans breed specific individuals from a species together to produce offspring with particular genes and desired traits. Humans have been doing this process for thousands of years, the most early examples being domesticating animals and producing crops from wild plants.
- Parents with specific desired traits are selected and bred together.
- Offspring that have the desired traits are selected and bred together.
- This repeats over many generations until the whole population will have the characteristic selected for.
Examples of selective breeding include:
- Breeding animals that produce the most meat or milk together can increase yields.
- Crops with disease resistance are be bred together to increase crop yields.
- Dogs have been selectively bred to have desired traits such as a gentle nature or to look a certain way.
- Plants can be selectively bred to have bigger or more unusual flowers for aesthetic purposes.
Issues with Selective Breeding
The organisms that are selected and bred together are often closely related, this is called inbreeding.
Inbreeding reduces the number of alleles in a population (gene pool) and can have serious repercussions on the population:
- Individuals will be more likely to inherit genetic defects.
- Lack of genetic variation could lead to whole populations could being killed by new diseases.
Selective Breeding Example Questions
Question 1: Describe the process of selective breeding.
[3 marks]
- Individuals with desired characteristics are bred together.
- Their offspring that have the desired characteristics are bred together.
- This continues over many generations until the whole population has the desired trait.
Question 2: Give an example of an organism that is selectively bred and the trait that is desired.
[1 mark]
Any one from:
- Farm animals – good at producing meat or milk.
- Crops – disease resistance.
- Dogs – gentle nature.
- Flowering plants – bigger / more unusual flowers.
Question 3: Name two issues that arise from inbreeding.
[2 mark]
Offspring are more likely to inherit genetic defects.
New diseases could kill whole populations.
Selective Breeding Worksheet and Example Questions
