What are the steps of selective breeding?

Decide the feature, choose the best parents, breed them, select the best offspring, repeat over generations.

Give two features that cattle are selectively bred for.

For example high milk yield and more meat.

Why do breeders select for disease resistance in crops?

Less of the crop is lost and less pesticide is needed.

Name two advantages of selective breeding.

For example higher yield, disease resistance, better quality, and it is cheaper and more accepted than genetic engineering.

Breeding between close relatives.

Why is inbreeding a risk?

It reduces genetic variation and makes harmful recessive alleles more likely to be inherited from both parents.

Why is low genetic variation a risk?

A new disease or change in climate could affect the whole population because none have resistance.

What decides which organisms breed in natural selection?

The environment, because the best adapted survive and reproduce.

How does selective breeding differ from natural selection in speed?

Selective breeding can change a population in fewer generations.

Why can selective breeding take a long time?

It needs many generations of choosing parents and breeding to build up the feature.

Selective breedingIB MYP Biology: Flashcards

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What is selective breeding?

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What is selective breeding?: Humans choosing which organisms breed so that useful characteristics are passed on.
What is another name for selective breeding?: Artificial selection.
What are the steps of selective breeding?: Decide the feature, choose the best parents, breed them, select the best offspring, repeat over generations.
Give two features that cattle are selectively bred for.: For example high milk yield and more meat.
Why do breeders select for disease resistance in crops?: Less of the crop is lost and less pesticide is needed.
Name two advantages of selective breeding.: For example higher yield, disease resistance, better quality, and it is cheaper and more accepted than genetic engineering.
What is inbreeding?: Breeding between close relatives.
Why is inbreeding a risk?: It reduces genetic variation and makes harmful recessive alleles more likely to be inherited from both parents.
Why is low genetic variation a risk?: A new disease or change in climate could affect the whole population because none have resistance.
Who decides which organisms breed in selective breeding?: Humans.
What decides which organisms breed in natural selection?: The environment, because the best adapted survive and reproduce.
How does selective breeding differ from natural selection in speed?: Selective breeding can change a population in fewer generations.
Why can selective breeding take a long time?: It needs many generations of choosing parents and breeding to build up the feature.

Exam questions on Selective breeding

A dairy farmer in New Zealand wants her cows to produce more milk. Each year she chooses the cows with the highest milk yield and breeds them with bulls whose mothers also gave a lot of milk. She then repeats this with the best of their calves, generation after generation.
Explain why the average milk yield of the herd increases over many generations.2 marks
Plant breeders in Kazakhstan produced a new variety of wheat that is resistant to rust, a disease caused by a fungus. They did this by crossing wheat plants and choosing the least damaged offspring over several generations. To test the new variety, they grew 50 plants of the original variety and 50 plants of the new variety in the same field. Both groups were sown on the same day and sprayed with the same number of rust spores. After four weeks, 31 of the original plants and 4 of the new plants showed signs of rust.
Calculate the percentage of plants showing rust in each variety.2 marks
Breeders of racing camels in the United Arab Emirates choose the fastest males and females as parents. A few champion males father large numbers of calves in many different herds, so many of the racing camels are now closely related. Wild gazelles in the same desert also run fast, because fast individuals are more likely to escape from predators.
State three differences between natural selection in gazelles and selective breeding in racing camels.3 marks

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Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).