Unit 7: Invertebrates

The characteristic of invertebrates :

-They haven’t got a spinal column or an internal skeleton.

-They are multicellular.

Body coverings of invertebrates

-Invertebrates can have a hard shell.-They also can have an exoskeleton.-Some of these animals have got a soft body

without protection.

Classification of invertebrates

We can find six groups of invertebrates:-Mollusks-Annelids-Echinoderms-Jelyfish and polyps-Arthropods-Sponges

Arthropods

The characteristics of arthropods are:-They have jointed parts and jointed legs.-They have an exoskeleton.

Arthropods can divided into four groups:-Insects-Arachnids-Crustaceans-Myriapods

Mollusks

The characteristics of mollusks are:-They’ve got soft body.-Most of them have a hard shell.-Many mollusks have a muscular foot.

Mollusks can divided into three groups:-Bivalves -Gastropods-Cephalopods

Sponges

The characteristics of sponges are:-They live in the ocean.-They can’t move around.-They are filter feeders.

Jelyfish and polyps

The characteristics of jelyfish and polyps are:-They live in the ocean.-They are carnivores.

Echinoderms

The characteristics of echinoderms are:-They live in the ocean.-They’ve got tiny feet with suction cups.

Annelids

The characteristics of annelids are:-They are worms with long, soft bodies.-Most of them live in water.-Their body is divided into segments.