Edexcel IGCSE Biology (b) Selective breeding Question Bank
Practise selective breeding by tracing parent choice, offspring selection and repeated breeding in crops, cattle, fish and dog populations.
- Syllabus
- First assessment 2019
- Course
- Biology 4BI1
Practise selective breeding by tracing parent choice, offspring selection and repeated breeding in crops, cattle, fish and dog populations.
The diagram shows a flower with some structures labelled.

A farmer has two varieties of a plant species.
One variety has a red flower colour and no scent.
The other variety has a white flower colour and a perfumed scent.
The farmer wants to produce a variety that has the red flower colour and the perfumed scent.
Explain how the farmer could achieve this.
An explanation makes reference to three of the following:
- selective breeding / artificial selection
- cross red (flower)/ unscented (flower) with white (flower) / scented (flower)/ eq
- select / breed / offspring with red and scent /eq
- repeat / for many generations eq
Ignore ref to GM as it is the farmer
Cross varieties / the plants
ignore desired characteristics alone
Reflexes are responses that protect the body and involve the central nervous system (CNS).
The photograph shows a breed of dog called a border collie.

Some border collies have a genetic condition called sensory neuropathy.
Border collies with sensory neuropathy may be injured as their reflexes do not work well.
Sensory neuropathy is caused by a recessive allele, n . The dominant allele for not having sensory neuropathy is N .
The diagram shows a family pedigree for some border collies.

Dog breeders use selective breeding to try to remove harmful alleles from dog breeds.
Explain how selective breeding could be used to remove the allele for sensory neuropathy from a population of border collies.
An explanation that makes reference to three of the following points:
- do a test cross to identify dogs that are NN / homozygous (dominant) / eq
- breed using dogs with no family history of sensory neuropathy / eq
- mate dogs that do not have sensory neuropathy / do not breed from dogs with sensory neuropathy / eq
- only allow homozygous dominant dogs to breed / breed with homozygous dominant dogs
- select / mate / breed from offspring that do not have sensory neuropathy / are homozygous dominant / eq
- repeat over several generations / eq
Allow mate
dogs that did not produce any offspring with sensory
neuropathy