Vertebrates and invertebrates

Fish, amphibians, reptiles, birds, mammals

Common chacteristic (p. 10): invertebrate

Table:

1. Starfish, sea anemone

2. Mussel, snail, octopus

3. Earthworm

4. Locust, cricket, cicada

5. Tick, spider, scorpion

6. Crayfish, prawn/shrimp, crab

7. Centipede, millipede

Group 1: 1, 2 and 3

Group 2: 4, 5, 6 and 7

Reason: presence or absence of exoskeleton (external skeleton) or articulated legs

Assignment 2:

Key: There are always two options, selection of an option must lead to insects. The following features must be included: invertebrate, arthropod, exoskeleton, six legs.

Can you still remember what you learned about the division of animals in Grade 6? You learned that animals can be divided into two main groups, namely the

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You also learned that vertebrates could be divided into five groups:

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We will study a number of examples of invertebrates. You will realise that they all share specific characteristics, but that, on the other hand, they also differ greatly from one another. We will use two methods to try to make it easy to understand and remember the similarities and the differences: firstly, we will determine how the animals are adapted for survival (this causes differences between different animals), and then we will classify the animals on the basis of the similarities and differences. If you classify things, it means that you group those with the same properties or characteristics together.

Biologists have already identified more than 2 million different types of living organisms and new types are still being discovered. There is a strict international code according to which living organisms are named, sorted and classified. It is based on the work of Linnaeus, who suggested that every organism should be given two names. Today, all living organisms have two scientific Greek or Latin names:

The complete name of the lion therefore is Panthera leo, while that of the leopard is Panthera pardus. The same is applicable to the invertebrates.

We will first do an overview of the invertebrates so that you can get to know the group with its smaller groupings. For this purpose, we will look at the similarities and differences between the animals.

Then we will study a few examples in greater detail so that you can discover how the animals are adapted to the conditions in their ecosystems.

CLASSIFICATION OF THE INVERTEBRATES

A number of different invertebrates are represented below.

Figure 1

Can you still remember what characteristic(s) is/are applicable to all these

animals? ____________________________________________________________

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Now try to divide them into approximately eight groups on the basis of their characteristics. In the following table, one or two characteristics of each group are provided to make it easier for you.

Now try to group the six groups in the table together to form two main groups:

Group 1 consists of groups __________________________________

Group 2 consists of groups __________________________________

Explain why you grouped them as you did:

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Compare your division with the following diagram:

Figure 2

Compile a key that will lead someone who has caught a strange insect to the answer that it is an insect.