Animals with Backbones

ANIMALS WITH NO BACKBONES

CHORDATA – animals with a spinal cord.

Sub – phylum: INVERTEBRATA – animals with no backbones.

This sub-phylum can be subdivided into eight groups: a) Coelenterates b) Molluscs c) Insects d) Crustacea e) Arachnids f) Worms g) Echinoderms h) Poriferans

CLASS CHARACTERISTICS EXAMPLES

Coelenterates 1. Marine Jelly-fish 2. Hollow body like a bag. Sea anemone 3. One opening into body. Coral 4. Have a ring of tentacles. Portuguese man of 5. Soft body. war 6. Corals build a stony wall around their bodies. Blue bottles

Molluscs 1. Some marine, some land dwelling. Slug 2. Soft body. Mussel 3. Most have a protective shell. Land snail 4. Large muscular foot. Octopus 5. No segmentation. Cuttlefish 6. Mouth and anus.

Insects 1. One pair of antennae. Fly 2. Body divided into three body parts: head, thorax and Ant abdomen. Moth 3. Three pairs of legs. Bee 4. Grow by moulting. Grasshopper 5. Many species winged as adults. Earwig

Crustacea 1. Marine Crab 2. Two pairs of antennae. Lobster 3. Gills Cyclops 4. Many appendages. Crayfish 5. Grow by moulting. Prawns

Arachnids 1. No antennae. Spider 2. Body divided into two body parts: cephalothorax and Mite abdomen. Scorpion 3. Four pairs of legs. Tick

Note: Insects, Crustacea and Arachnids are all Arthropods. They are animals that have jointed legs. CLASS CHARACTERISTICS EXAMPLES

Worms a) Flat worms – 1) mostly leaf shaped. a) Tapeworms (Platyhelminths) 2) have both male and female parts. Flukes 3) Only one opening. 4) Most are parasitic.

b) Roundworms – 1) long, slender and tough skinned. b) Barber pole (Nematodes) 2) two openings. Roundworm 3) Males and females are separate Trichina worm animals. Hook worm 4) Some are parasitic.

c) Segmented - 1) rings or segments make up body. c) Earthworm Worms 2) bilaterally symmetrical. Leech (Annelids) Bristle worm

Echinoderms 1. Marine Starfish 2. Adults radially symmetrical. Brittle star 3. Unsegmented Sea Urchin 4. Tube feet. Sea cucumber 5. Limy plates (or spines) in their skin. 6. Can survive loss of body parts and regrow them.

Poriferans 1. Marine Sponges 2. Spongy body with many holes. 3. One large hole for wastes. 4. Food and water enter through tiny holes in body.