17.1 Variation (Cambridge (CIE) O Level Biology): Flashcards
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Define variation.
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Cards in this collection (12)
Define variation.
The differences between individuals of the same species.
Define continuous variation.
Variation showing many small degrees of difference for a characteristic, which can be measured on a scale.
Define discontinuous variation.
Variation showing distinct differences for a characteristic, with no intermediate values.
What are the two main causes of phenotypic variation?
Phenotypic variation can be caused by:
genetic factors
environmental factors
When plotted on a graph, continuous variation produces a smooth curve.
When plotted on a graph, continuous variation produces a smooth bell-shaped curve.
Discontinuous variation is usually caused by variation alone.
Discontinuous variation is usually caused by genetic variation alone.
True or False?
Height is an example of continuous variation.
True.
Height varies through many small degrees and is measured on a scale.
True or False?
Blood group is an example of continuous variation.
False.
Blood group shows distinct categories, so it is an example of discontinuous variation.
Give two examples of genetic variation in humans.
Examples of genetic variation in humans include:
blood group
eye colour
Why is continuous variation often caused by both genetic and environmental factors?
Genes give an individual the genetic potential for a characteristic, but the environment (such as diet) affects how far that potential is reached.
How is discontinuous variation usually presented on a graph?
As a bar chart.
Give one example of environmental variation.
Scarring caused by an accident.
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