Flashcards · Biology · Inheritance
Variation and Mutations
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What is variation?
The differences between individuals of the same species.
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What is discontinuous variation?
Variation in which individuals fall into distinct categories.
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Give an example of discontinuous variation.
Eye colour, or blood group.
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What is continuous variation?
Variation in which a feature can have any value in a range.
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Give two examples of continuous variation.
Height and weight.
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Which type of graph shows continuous data?
A histogram, with touching bars.
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Which type of graph shows discontinuous data?
A bar chart, with gaps.
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What are the causes of variation?
The genome, the environment, or both.
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Give an environmental cause of variation.
Scars, a suntan, or an accent.
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Where do all variants come from?
Mutations.
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What effect do most mutations have?
No effect on the phenotype.
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What does a mutagen do?
Increases the rate of mutation.
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Name two mutagens.
Ionising radiation and some chemicals, or ultraviolet light.
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Why does sexual reproduction not make new variants?
It only mixes the existing ones into new combinations.
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Why use a large sample in an investigation of variation?
The results are more reliable, and less biased.
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Common mistake about mutations?
Saying that all of them are harmful. Most have no effect.