Flashcards · Biology · Reproduction, Meiosis and Variation
Causes of Variation
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What is variation?
The differences between individuals of the same species.
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Give two causes of genetic variation.
Mutation and sexual reproduction.
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What is environmental variation?
Differences caused by the environment, such as diet or accidents.
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Are acquired characteristics inherited?
No.
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Give an example of an acquired characteristic.
A scar, a tan, or knowing how to speak French.
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Give an example of a genetic characteristic.
Blood group or eye colour.
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Give an example of a feature caused by both genes and the environment.
Height or body mass.
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Are most features controlled by one gene or many?
Many genes.
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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 an example of continuous variation.
Height, mass or leaf length.
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What is discontinuous variation?
Variation in which a feature falls into separate categories.
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Give an example of discontinuous variation.
Blood group, or sex.
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Which type of graph is used for discontinuous data?
A bar chart, with gaps between the bars.
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Which type of graph is used for continuous data?
A histogram or line graph.
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Why do identical twins help to study the causes of variation?
They have the same genes, so differences between them are due to the environment.
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Why should a sample be random and large?
To avoid bias and make the results more reliable.