INVERTEBRATES

MAIN CHARACTERISTICS

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

• Invertebrates have got different body covering

• Hard shell

• Rigid covering Exoskeleton

• Without protection

MAIN GROUPS

Mollusks

Jellyfish and polyps

Sponges

Annelids

Arthropods

Echinoderms

• They have got a rigid body covering or exoskeleton.

• Their bodies are divided into jointed parts.

• They’ve also got jointed legs that they can bend.

ARTHROPODS

THEY CAN BE SEPARATED INTO FOUR GROUPS:

INSECTS

• They have 6 legs.• Their bodies have 3

parts: head, thorax and abdomen.

ARACHNIDS

• They have 8 legs.• Their bodies are

divided into 2 parts: cephalothorax and abdomen

CRUSTACEANS

• They have 10 legs and a very hard exoskeleton.

• Their bodies are divided into 2 parts: cephalothorax and abdomen.

MYRIAPODS

• They have many legs.

• Their bodies are divided into 2 parts: head and trunk.

abdomen cephalotorax

• They’ve got a soft body.

• Most mollusk have a hard Shell. They have also a thin layer next to

their shell called the mantle. It protects their organs.

• Many mollusks have a muscular foot which they use to move

around.

MOLLUSKS

THEY CAN BE SEPARATED INTO 3 GROUPS:

BIVALVES

• Have a Shell with 2 parts called valves.

• Soft body and no head.• They are filter feeders

(They filter water to extract nutrients)

GASTROPODS

• Can have a Shell or not.• They have a head and

body and 4 tentacles.• Most of them are

herbivores.

CEPHALOPODS

• They have a head with a mouth and well-developed eyes.

• They have long arms to catch their food and some of them have tentacles.

• Most of them are carnivores.

• Almost all of them live in the ocean.

• Sponges can’t move around. They stay in one place.

• They have a soft body with holes called pores. Sponges are filter feeders.

They filter water through their pores to extract nutrients.

SPONGES

• Almost all of them live in

the ocean.

• They are carnivores.

JELLYFISH AND POLYPSJellyfish

They float and swim in the ocean.

The mouth is on the underside of the body.

PolypsThey have a body that is shaped like a

bag.

They have a suction cup at one end of their body to anchor themselves to

the floor.

ECHINODERMS

• They live in the ocean

• They have many tiny feet with

suction cups. They use these

feet to move across the ocean

floor.