Invertebrate Animals

Classification of Animals

Scientists have divided the Animal Kingdom into two main groups:

vertebrates (animals with a

backbone)

invertebrates (animals without

a backbone)

and

Invertebrates

Animals without a backbone.

Vertebrates

Animals with a backbone.

InvertebratesAnimals without backbones can be divided into seven

more groups:

Arthropods

Molluscs

Echinoderms

SpongesWorms

Jellyfish

Corals

InvertebratesEach group is divided into other groups:

MOLLUSCS

Gastropods

Arachnids

Crustaceans

Myriapods

ARTHROPODS

InsectsBivalves

Cephalopods

ARTHORPODS: general characteristics

• Biggest group of invertebrates

• CRUSTACEANS

• Lay eggs.• Have exoskeleton• Have lungs and need

air to breathe.

• Have 6 legs.

• ARACHNIDS

• INSECTS.

• MYRIAPODS

INSECTSBiggest group of Invertebrates• They have 6 legs and two antennae

• They have exoskeleton.

• They lay eggs.

• Most of them have wings like the wasp, the bee, the butterfly

INSECTS• Their body is divided into three parts:

• ABDOMEN• THORAX• HEAD

Arachnids• Have exoskeleton.

• 4 antennae.• Two eyes.

• Most have 8 legs and 2 claws.

• Lay eggs.

• A spider is an arachnid.

Arachnids

• A scorpion is an arachnid.• A tick is an arachnid.

• A spider is an arachnid.

MOLLUSCS

Molluscs can be divided into three subgroups:

Molluscs have a soft body.They lay eggs, so they are oviparousThey live in water or moist placesSome have a shell.

Gastropods Cephalopods Bivalves

MOLLUSCSSHELL.

SOFT BODY.

ANTENNAE.

MOLLUSCS

Squids are molluscs.

Mussels are molluscs.

Snails are molluscs.

OTHER INVERTEBRATES• Cnidarians have tentacles.

– Corals and Jellyfish are cnidarians

OTHER INVERTEBRATES• Echinoderms live in the water.. Echinoderms include starfish, sea

lilies, feather stars, brittlestars, sea cucumbers, and sea urchins.

OTHER INVERTEBRATES

• Annelids are segmented worms. • Their boy is divided into many little

segments.• Earthworms and leeches are annelids