1.3 General science

Natural sciences

Life and way of living

Educator section

Memorandum

Assignment 1:

An instrument that is used to identify a plant or an animal (to determine the name). It provides options according to which the characteristics of the plant or animal can be selected to serve as a guide to the answer (the name of the relevant plant or animal).

Activity 4: to categorise plants by comparing their characteristics [lo 2.2]

The development of a key with which to classify plants

You have now been introduced to various characteristics of plants and have learned that we can group the plants in terms of their characteristics. A lot of work has already been done in this regard by biologists and all the plants that are known to people have already been divided into groups. New plants that are discovered can also be placed into a group immediately.

The advantage of this is that we can identify any plant that we see, find out its name and discuss it with other people. For example, we can determine whether a plant is indigenous or exotic, whether it is a harmful weed, what we can do with it, etc.

To be able to identify a plant we can make use of a key . We will now use our knowledge about plant characteristics and plant groups to compile our own key.

The easiest way is to pretend that you have seen a particularly interesting plant and want to go to a plant expert (botanist) to ask him/her to which group the plant belongs. Try to think what type of questions you would ask such a person in order to find out the answer.

The person most probably will ask questions to which you can answer yes or no. In this manner, it is possible to use each question to eliminate one possibility and thereby to move in the direction of the answer.

Let us try. Use the diagrammatic division of plants on the previous page and work through it from top to bottom on the basis of the questions that follow:

1. Does the plant form seeds?

• Yes ____________________________________________________

(Proceed to 2)

• No ___________________________________________ Algae or mosses

(Proceed to 4)

2. Does the plant bear flowers?

• Yes _____________________________________________ (Proceed to 3)

• No _______________________ Coniferous plants, e.g. fir tree (Proceed to 12)

3. Does the plant have vein-like leaves or does it have an adventitious root?

• Yes ________________ Dicotyledonous plants e.g. proteas (Proceed to 20)
• No ____________ Monocotyledonous plants, e.g. grasses (Proceed to 40)

Assignment 1:

Describe in your own words what a key for the identification of plants or animals is and how it is used.

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Assessment

Learning Outcome 2: The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

Assessment Standard 2.2: We know this when the learner categorises information (can compare the properties of categories of organisms).