Invertebrates

What is an invertebrate?

• An animal that has no backbone

• Most animals in the world are invertebrates

• Most invertebrates are smaller than vertebrates.

V erteb ra tes(H a v e b a ck b on e)

In v erteb ra tes(N o b a ck b on e)

A n im a lK in gd om

P or i fe ra

C n id ar ia

W orm s(An ne lid s)

M o llu sk

E ch in od erm s

A r th rop ods

In ve rte b ra tes

Porifera• Aquatic• Multicellular• Tiny pores all over

their bodies• Example:

– Sponge

Cnidaria• Aquatic• Soft-bodied• Stinging tentacles• Examples:

– Hydras– Jellyfish– Sea Anemones– Coral

Hydra

Jellyfish

Sea Anemone

Coral

Worms

• No shells• No legs• No eyes• Examples:

– Earthworms

– Tapeworms

– Sandworms

Mollusks

• May have a hard outer shell, but not always

• Examples:– Snails

– Clams

– Squid

– Octopus

– slugs

Snail

Clams

Squid

Squid

Octopus

Echinoderms

• Aquatic• Spiny-skinned• 5-part symmetrical

body• Examples:

– Starfish– Sea Urchin– Sand Dollar– Sea Cucumber

Starfish

Sea Urchin

Sand Dollar                                           

Sea Cucumber

Arthropods

• Jointed legs• 2 or more body parts

– Head– Thorax– Abdomen

• Often have exoskeleton

• 850,000 species we know of so far!

I n sects

S p id er s

M i tes

C r a bs

S cor p ion s

A r th r opods

Arachnids• Two body parts:• Cephalothorax• Abdomen• 4 pairs of legs• Can regrow legs• 8 eyes• Poison glands in jaw• Spinnerets on end of

abdomen for webs

Don’t get ticked!

…or stung by a scorpion!

Crustaceans

• Head• Thorax• Abdomen• 3 pairs of legs• Swimmerets

Mmmm…lobster

Don’t be crabby!

                      

Hey Shrimp!Hey Shrimp!!

Insects• Head• Thorax• Abdomen• 6 legs• Compound Eyes

Millipedes

• Two pairs of legs per segment

• Rounded body• Not poisonous

Centipedes

• One pair of legs per segment

• Flat body• Poison claws behind

head• Paralyze prey

Aren’t invertebrates

fun?