S4.2.7 For the adult
Variation
Why are no two people exactly alike, even in one family?
What this chapter teaches
Variation comes from genes, from the environment, or from both. Discontinuous variation falls in separate groups, and continuous variation takes any value in a range. A histogram shows continuous data in classes, with bars that touch. With classes of equal width, the height of a bar is its frequency.
Three questions to ask
There is no one right wording. Listen for the idea.
- Why do identical twins sometimes differ, even though they have the same genes?
- What is the difference between a bar chart and a histogram?
- Is height caused by genes, the environment or both, and how do you know?
After the chapter, the learner can
- Sort features into ones caused by genes, surroundings or both
- Collect hand spans from family and friends and plot a histogram
What they copy into their notebook
Variation comes from genes, the environment, or both. Blood group falls in separate groups. Height can take any value in a range. A histogram has touching bars. With classes of equal width, the height of a bar is its frequency.