Variation
Five kittens from one litter, and no two look alike. Differences between members of the same species are called variation. Some come from genes, some from the surroundings, and they decide who survives when conditions change.
By the end of this page you can
- Explain how genetic variation arises, and why it matters
- Sort features into continuous and discontinuous variation
- Define mutation and the two kinds of variation
- Answer exam questions on variation
Goals tick themselves off as you try the activities below.
Photo: Jan-Mallander, CC0, via Wikimedia Commons. Cropped, JPEG q72.
One litter, five coats. Each kitten inherited a different mix of its parents’ alleles.
How often it shows up in past papers
Paper 1 counts come from our past-paper bank of CSEC Biology Paper 1s. Paper 2 is not included yet.
Three causes of difference
Two causes change the genes and can be inherited. The third does not. Tap each card.
A range, or separate groups?
Continuous variation has a full range of values in between. Discontinuous variation falls into separate groups with nothing in between. Tap each feature.
Continuous or discontinuous?
Tap a feature on the list to see which kind of variation it shows.
Discontinuous variation is also called discrete variation. Draw continuous data as a histogram (touching bars) and discontinuous data as a bar chart (separate bars).
Seven terms to know cold
Say what each term means before you flip the card. “Distinguish between” questions need an example for each side.
Six quick questions, then a real one
Pick an answer to see why it’s right or wrong.
Which feature shows DISCONTINUOUS variation?
Which feature shows CONTINUOUS variation?
Which of these is a source of GENETIC variation?
Why is genetic variation important to a species?
Students measure the hand span of 40 classmates. Which graph should they draw?
A hydrangea flowers blue in one garden and pink in another. This difference is
exam style · 3 marks
Distinguish between continuous and discontinuous variation. Give ONE example of each.
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Practice questions are written by My V.I.P. Academy. They are not official CXC papers.