Page 154 - Big Ideas Year 10 sciPAD 2025

PHOTOCOPYING PROHIBITED
© Silverback Academic Media
154 SCIPAD - BIG IDEAS - BOOK 2
THE BASIS OF HEREDITY
Types of Variation
Variation can be described as being continuous or discontinuous.
In continuous variation there is a complete range of measurements from one extreme to the other.
For example, human height ranges from the shortest person in the world to the tallest person.
Humans could be any height in between these values.
Discontinuous variation occurs when characteristics fall into a number of distinct classes or
categories. For example, your ear lobes can either be “fixed” to the side of your head, or “free” to
dangle. There is no in-between.
Measuring Variation I
Aim: To measure the variation in eye colour within the class.
Method: 1. Working in pairs if required, record the colour of each other’s eyes.
2. Your teacher will get the class to tick the correct box on the board so that you can
copy down the variation in eye colour for the entire class. Record the class results in
the table below.
3. Process your data by plotting a bar graph of your class’s results.
Results: My eye colour: 
Class tally:
Blue Green Brown Hazel
1. State whether eye colour is an example of continuous or discontinuous variation. Justify
your answer. 



Unchecked Sample Pages
For Review Purposes Only - Photocopying Prohibited
www.scipad.co.nz