What do animals have in common?
Symmetry. Most animals have symmetrical bodies. This means that the body parts are the same on both sides of the animal.
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| Anatomic body planes |
Body organisation. Most animals have organs and systems. These help them to perform the vital functions.
Interaction. All animals interact with their environment using the sense organs connected to their nervous system. The sense organs are located in the body.
How do we classify animals?
We can classify animals into vertebrates and invertebrates.
Vertebrates have a backbone.
They also have an internal bone skeleton.
Their bodies have a head, a trunk and limbs. There are five groups of vertebrates: fish, amphibians, reptiles, birds and mammals.
Invertebrates do not have a backbone or an internal bone skeleton.
Some invertebrates have a hard shell, or exoskeleton, to protect their body organs. Most invertebrates are oviparous. This means that they lay eggs.
