invertebrates

INVERTEBRATES

• Invertebrates are the biggest group of animals on Earth.

ANIMALS

VertebratesInvertebrates

INVERTEBRATES

• Invertebrates don’t have a backbone.

INVERTEBRATES

INVERTEBRATES

ARTHROPODS

MOLLUSKS

WORMS

ECHINODERMS

PORIFERANS

CNIDARIANS

CEPHALOPODS

BIVALVES

GASTROPODS

INSECTS

ARACHNIDS

CRUSTACEANS

INVERTEBRATES

MYRIAPODS

MOLLUSKS

• They don’t have skeletons or exoeskeletons.

• Mollusks have soft bodies.

MOLLUSKS

• Mollusks don't have legs, though some have flexible tentacles.

• Most mollusk species grow a hard shell for protection.

MOLLUSKS

• There are three main groups of mollusks:

GASTROPODS BIVALVES

CEPHALOPODS

GASTROPODS (MOLLUSKS)

• About 70-80% of all mollusk species are gastropods.

• The term Gastropod means “stomach-foot”


• Nearly all gastropods grow a spiral shell that is all one piece.

NOT ALL GASTROPODS HAVE SHELLS

BIVALVES (MOLLUSKS)

• All are aquatic.

• They are called bivalves because they have two shells. They can close up tight for protection.

BIVALVES (MOLLUSKS)

• One process that is unique to bivalves, is pearl formation.

BIVALVES (MOLLUSKS)

CLAM MUSSEL

OYSTER

CEPHALOPODS (MOLLUSKS)

• It means “head-footed”. • Cephalopods have “feet” which are attached

to the “head” containing their eyes. • The “feet”, which are also called “arms” or

tentacles, are utilized for jet propulsion.


• They only live in salt water.• They have big eyes. • They are all predators; they eat fish,

crustaceans, and other mollusks.


• Some cephalopods may segregate a black ink to hide.


SQUID(10 LEGS)

OCTOPUS(8 LEGS)

ARTHROPODS

There are more than 1 million kinds of arthropods on Earth.

ARTHROPODS

• All arthropods have got three characteristics:

- EXOSKELETON

- SEGMENTED BODY

- JOINTED LIMBS

ARTHROPODS

This is an external skeleton. Like armor, it protects the arthropods body.

1. EXOSKELETON

Molting is to leave an exoskeleton and grow a new one.

ARTHROPODS

This means that they will have a body made up of more than one part. Spiders have two segments and flies have three segments. They have symmetrical bodies.

2. SEGMENTED BODY

ARTHROPODS

All arthropods have jointed limbs. This means their arms or legs can flex and bend at joints.

3. JOINTED LIMBS

ARTHROPODS

• There are four main groups of arthropods:

INSECTS

• There are more kinds of insects than there are all other animal species all together.

INSECTS

• All insects have three parts: the head, the thorax and the abdomen.

• Insects have two antennae and six legs.

INSECTS

• All insects hatch from eggs. The babies are called larva.

INSECTS

• Some insects go through the same life cycle.

1) Life begins as an egg. 2) The egg hatches and larva emerge. 3) The larvae enter a pupa, chrysalis or cocoon.4) An adult insect emerges from the pupa.

INSECTS

(Ladybird)

FLY WASP STICK BUG

CRICKET PRAYINGMANTIS

COCKROACH

CRUSTACEANS

• Crustaceans have two pairs of antennae and they often have many legs.

CRUSTACEANS

• Most crustaceans live in water and get oxygen from the water through gills.

CRUSTACEANS

• Crabs and shrimp can swim. • Lobsters just scuttle about on the bottom of

the ocean. • Barnacles stick themselves to a hard surface

like a rock or a boat and never move.• Hermit crabs can’t make their own shells. They

hide in shells left behind by other animals.

CRAB SHRIMP LOBSTER

BARNACLE HERMIT CRAB

ARACHNIDS

• Arachnids have two parts: the cephalothorax, and the abdomen.

ARACHNIDS

• Arachnids have eight legs• They don’t have antennae or wings.

ARACHNIDS

• Many of them spin webs.

ARACHNIDS

• All spiders have venom, but only a few kinds of spiders are dangerous to people.

• Scorpions have a stinger and strong pincers to deal with prey.

SPIDER SCORPION

TICK

MYRIAPODS

They look a little like worms with lots of legs. They have one pair of antennae.

CENTIPEDE(Flat body and fewer legs)

MILLIPEDE(Round body and more legs)

ECHINODERMS

• They live in the sea (salt water).• “Echinoderm” means “spiny skin”.

ECHINODERMS

• They have a radial simmetry: 5 or more arms radiating from a central body.

ECHINODERMS

• They can regenerate its body parts: They have the ability to regrow lost limbs or

other body parts, even internal organs. Some species can use regeneration to reproduce.

ECHINODERMS

• They don’t have eyes.• They don’t have blood or heart.• They don’t have a brain.

ECHINODERMS

STARFISH SEA URCHIN

WORMS

• There are around 2700 different types of worm.

• They have a bilateral simmetry and no legs.

• Biologist classify worms into three groups:

WORMS

• Most worms are hermaphrodites and have both male and female organs.

WORMS

EARTHWORM

LEECH

CNIDARIANS

• All of them are simple and aquatic, and most of them live in the sea.

CNIDARIANS

• They are usually symmetrical and they have body with a mouth opening. They have stinging cells on tentacles around the mouth.

JELLYFISH

CORAL SEA ANEMONE

PORIFERANS (SPONGES)

• They live in water and most poriferans don’t move.

(There are a few sponges that can move. They race along the ocean floor at a whopping 1-3 millimetres a day!)


• Sponges can change the shape of their bodies. They don’t have a symmetrical body.


• Porifera have no mouth or organs in their bodies. They have got pores.


• Very few animals eat sponges so they can live for a very long time. Some types have been found to live over 200 years!

invertebrates

Education