1. Classifying living things
When we find out something new, we fit it in amongst all the things we already know. We build up our own big picture (organising system) in our heads. That’s how the human mind works.
Think about how we organise our ideas of a family. We can represent this in a diagram called a family tree, where you place people where they belong in the big picture. Resource 1: An African family tree shows a typical family tree. You might like to create your own family tree to share with your pupils, or that of a famous person.
This is how it is with biology. As a teacher, you need to help your pupils to build up a useful big picture of living things and how they are related. There is an agreed organising system that scientists have developed over years. Resource 2: The current agreed classification of living things shows how biologists organise living things into kingdoms and some of their subdivisions.
A good way to start helping pupils organise their ideas about living things is to begin with items in your own environment – objects that pupils are familiar with and can easily investigate. Case Study 1 shows how one teacher did this with her class and Activity 1 shows how to make a display in your own classroom. If your pupils can start to classify (sort) these items into groups, they will be behaving as scientists.
Case Study 1: The big picture of living things
Amaka Ukwu’s pupils in Nguru, Nigeria, were surprised to find two new tables in the class. Without saying anything, Ms Ukwu carefully laid out four self-standing cards in specific positions on the tables. ‘Non-living’ on the table to the left and ‘Living’, ‘Plants’ and ‘Animals’ on the table to the right.
Ms Ukwu gave the class five minutes to go outside and find different examples of non-living things. She talked about what they brought back and helped them to group similar things together on the non-living table. Ms Ukwu deliberately checked that things like bone, wood, cardboard and paper were on the side nearer to the living tables. Why did she do that?
Next, each pupil was given a small self-standing card and asked to draw any plant or animal on one side and write its name on the back. It must be different from anyone else’s. The cards were brought to the front and sorted, displayed and discussed. Ms Ukwu ensured that like was sorted with like. (She had in mind the organising diagram from Resource 2 but chose not to confuse her pupils by telling too much too soon.)
Ms Ukwu completed the lesson by asking the pupils to look at all the non-living things and divide them into those that were once living and those that were never alive. The pupils worked in groups and had lively discussions about many of the exhibits.
Activity 1: Collecting evidence of life around us
Tell your pupils that they will be developing a display to show non-living and living things around them. Explain that it would not be right to display real animals and plants. They should not damage or kill anything living. Instead, rather like detectives, they should hunt for clues and evidence of any living thing – for example, feathers, droppings, leaves and seeds. Give pupils several days to bring in things for the display. Now talk about the groupings you will have (animals, plants and so on), what defines each group and where each item sits in the display. Pupils could then make labels for the display.
In the next science lesson, choose six things from the display – three living and three non-living – and display them on another table.
Gather your pupils round the table and ask them which of the six things are living and how they know this. By careful questioning and discussion you should be able to draw up a list of the seven characteristics of living things. Resource 3: The seven common characteristics of all living things gives you ideas for this work on the characteristics of plants and animals.