Cambridge IGCSE · Biology 0610
IGCSE Biology: Variation and selection — Practice Questions & Answers
IGCSE Biology variation and selection: continuous and discontinuous variation, mutation, adaptive features, natural selection and selective breeding explained simply.
849 practice questions available for this topic — here are 10 with full answers and explanations.
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Practice questions with answers
1
Multiple choice · Easy
What is variation?
- The differences between individuals of the same species
- The differences between different species
- The passing of genes from parents to offspring
- A permanent change in a gene
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WhyVariation is the differences between individuals of the same species.
2
Multiple choice · Easy
Which of these is an example of continuous variation in humans?
- Height
- Blood group
- Tongue rolling
- Ability to roll the tongue
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WhyHeight shows a continuous range of values with no distinct categories.
3
Multiple choice · Easy
Which of these is an example of discontinuous variation in humans?
- Blood group
- Height
- Body mass
- Foot length
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WhyBlood group falls into distinct categories with no intermediates.
4
Multiple choice · Easy
What is a mutation?
- A genetic change (a change in the base sequence of DNA)
- A change in environment of an organism
- The mixing of genes during reproduction
- A feature that helps an organism survive
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WhyA mutation is a random change in the base sequence of DNA (a gene).
5
Multiple choice · Easy
What is an adaptive feature?
- An inherited feature that helps an organism survive and reproduce in its environment
- Any change that happens during an organism's lifetime
- A learned behaviour passed to offspring
- A feature caused only by the environment
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WhyAn adaptive feature is an inherited feature that helps an organism survive and reproduce in its environment.
6
Multiple choice · Easy
Which graph shape is typical of continuous variation when plotted as a frequency distribution?
- A smooth bell-shaped curve
- A few separate bars with no intermediates
- A straight horizontal line
- A single tall bar only
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WhyContinuous variation typically produces a smooth bell-shaped (normal distribution) curve.
7
Multiple choice · Easy
Selective breeding is also known as which of the following?
- Artificial selection
- Natural selection
- Random mutation
- Genetic engineering
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WhySelective breeding is also called artificial selection because humans choose which organisms reproduce.
8
Multiple choice · Easy
Which of these is a feature of a xerophyte (a plant adapted to dry conditions)?
- Reduced leaves or spines to reduce water loss
- Large thin leaves to lose water quickly
- Shallow non-spreading roots only
- A thin waxy-free cuticle
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WhyReduced leaves or spines lower the surface area for water loss by transpiration.
9
Multiple choice · Medium
Which factor is the cause of genetic variation between offspring of sexually reproducing organisms?
- New combinations of genes from two parents
- Cuttings taken from one parent
- Identical copying of one parent's DNA only
- The diet of the offspring
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WhySexual reproduction creates genetic variation through new gene combinations; mutation also produces variation.
10
Multiple choice · Medium
A bodybuilder develops large muscles through training. Why are these large muscles NOT passed on to their children?
- They are caused by the environment and do not change the genes in the gametes
- They are caused by a mutation in body cells
- They are an example of discontinuous variation
- Muscle size is controlled only by a single gene
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WhyAcquired (environmental) characteristics are not coded in the DNA of gametes, so they are not inherited.
Key terms in Variation and selection
Variation: The differences in the characteristics that exist between individuals of the same species.
Species: A group of organisms that share similar characteristics and can interbreed to produce fertile offspring.
Phenotype: The observable physical, biochemical or behavioural characteristics of an organism, produced by its genes and the environment.
Genotype: The combination of alleles that an organism carries for a particular characteristic.
Characteristic: A particular feature or trait of an organism, such as height, eye colour or blood group.
Trait: A specific version of a characteristic shown by an individual.
Continuous variation: Variation that produces a range of phenotypes between two extremes with no distinct groups, such as human height or mass.
Discontinuous variation: Variation that produces a limited number of distinct phenotypes with no intermediate values, such as the ABO blood groups.
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