THE STUDY OF LIVING THINGS
INVERTEBRATES
| Protozoa |  One-celled animals, such as amoeba, belong
to the protozoa phylum. Protozoa usually live in water - in
the sea, in ponds or in damp places like puddles. |
|
| Coelenterates |   Coelenterates (pronounced see-elenterates)
are animals with soft, hollow bodies and tentacles.
Jellyfish, sea anemones and corals are all coelenterates.
|
|
| Annelids |  Garden worms belong to a phylum called
annelids. They have soft bodies, divided into rings or
segments. Worms move by relaxing and contracting
muscles in their bodies. |
|
| Arthropods |  Arthropods have an exoskeleton,
jointed legs and antennae. Their bodies are usually
divided into three sections - head, thorax and abdomen.
There are four main classes of arthropod. |
|
| 1. Insects |  Insects have six legs, two pairs of wings, two
antennae and two compound eyes. 70% of all animals
are insects. |
|
| 2. Arachnids | Scorpions and spiders are arachnids. They have eight legs, no antennae, and simple rather than compound eyes. | |
| 3. Myriapods | These are arthropods with many legs, such as centipedes and millipedes. | |
| 4. Crustaceans | They have from 10 to 14 legs, two pairs of antennae and respire by means of gills. Shellfish such as crabs and prawns. | |
| Molluscs | Soft-bodied animals with a single foot. Snails, slugs and mussels are all molluscs. | |
| Echinoderms | Spiny-skinned animals, such as starfish and sea urchins. | |
 |
 |
 |
 |