Invertebrates

INVERTEBRATESINVERTEBRATES

Small animals which live Small animals which live with uswith us

PoriferaPorifera The body is The body is like a sack like a sack full of pores full of pores and and channels.channels.

Water Water circulates circulates through it, through it, and the cells and the cells get the get the small small plancton.plancton.

Porifera Porifera don’t have don’t have one one skeleton. skeleton. Instead, Instead, they have a they have a lot of small lot of small and tough and tough pieces, pieces, called called spicules.spicules.

They live They live attached to attached to a surfacea surface

CnidariaCnidaria They have They have

a soft body a soft body and a and a mouth mouth surrounded surrounded by by tentacles.tentacles.

There are There are two body two body types: types: polyps and polyps and medusae medusae (jellyfish).(jellyfish).

Polyps live Polyps live attached to attached to a surface.a surface.

Jellyfish float in the seaJellyfish float in the sea

They have a complex life cycle, while They have a complex life cycle, while you can see in this picture…you can see in this picture…

WormsWorms

There are There are many many types of types of true true worms.worms.

This is This is not a not a wormworm

Nor this.Nor this.

All these animals are larvae of All these animals are larvae of insects…insects…

These , instead, These , instead, are really wormsare really worms

They have a soft body and no They have a soft body and no skeleton.skeleton.

PlatyhelminthesPlatyhelminthes

They They have have long, long, flat and flat and soft soft bodiesbodies……

Some of Some of them are them are parasiticparasitic……

Not all.Not all.

NematodesNematodes

They have They have cylindrical cylindrical bodies, bodies,

not not

divided into divided into segments, segments, ……

Not like Not like this…this…

AnnelidsAnnelids

They have They have a soft, a soft, cylindrical cylindrical body, body,

but but

divided into divided into segments, segments, ……

This group have three small groups a This group have three small groups a bit differents:bit differents:

Leeches,Leeches,

With no hairs or chetae in its skin…With no hairs or chetae in its skin…

Oligochaeta,Oligochaeta,

worms with small groups of chetae worms with small groups of chetae or hairs over its skin,or hairs over its skin,

like the earthwormlike the earthworm

And And polychaetespolychaetes,,

sea wormssea worms

with a lot of with a lot of hairs, hairs, usually at usually at the top of the top of small limbssmall limbs

MolluscsMolluscs

They have They have a soft a soft body body divided divided into three into three parts: parts: head , head , body body mass and mass and foot.foot.

They They breathe breathe through through gills…gills…

(Aquatic)(Aquatic)

But some But some breathe breathe through through lungs…lungs…

(terrestrial)(terrestrial)

And they go through metamorphosisAnd they go through metamorphosis

There are three main groups of There are three main groups of molluscs:molluscs:

Gasthropoda, without or with a spiral Gasthropoda, without or with a spiral shell, terrestrial or aquaticshell, terrestrial or aquatic

Bivalves, with a shell, with two Bivalves, with a shell, with two valves, ever aquaticvalves, ever aquatic

Cephalopods, with an internal shell, Cephalopods, with an internal shell, or without it, and the foot divided or without it, and the foot divided into tentaclesinto tentacles

ArthropodsArthropods They They have have jointed jointed legs and legs and an an external external skeleton.skeleton.

Their Their bodies bodies are are divided divided into three into three parts: parts: head, head, thorax thorax and and abdomenabdomen. .

And they can undergo And they can undergo metamorphosismetamorphosis

Some have the head join to the Some have the head join to the thorax forming a cephalothoraxthorax forming a cephalothorax

Like the crustaceans and the Like the crustaceans and the arachnids …arachnids …

ArthropodsArthropods The The

Crustaceans Crustaceans live in the live in the sea.sea.

Some form Some form one one important important part of the part of the zooplancton, zooplancton, that feed the that feed the fisheries.fisheries.

The arachnids are not ever like this The arachnids are not ever like this animal …animal …

Others had Others had only the only the head and head and the trunk…the trunk…

The The myriapodamyriapoda

Finally, we Finally, we have in this have in this group the group the most most beautiful beautiful arthropods. arthropods.

The insectsThe insects

Some undergo Some undergo metamorphosis,metamorphosis,

Others not.Others not.

Some have Some have wings,wings,

Others not.Others not.

Some are Some are common,common,

Some are Some are strange…strange…

EchinodermsEchinoderms They have They have

an internal an internal skeleton skeleton made up of made up of plaques plaques under their under their skin.skin.

They They breathe breathe through through their skin, their skin, using the using the ambulacral ambulacral apparatus.apparatus.

They They undergo undergo metamorphmetamorphosis.osis.

There are five There are five groups of groups of echinoderms.echinoderms.

It could be It could be that you that you know two of know two of them…them…

The starfish The starfish or or asteroidea…asteroidea…

The Sea urchins or echinoideaThe Sea urchins or echinoidea

But in this group we have too,…But in this group we have too,…

the ophiuroidea orthe ophiuroidea or brittle starsbrittle stars

The Sea lilies or crinoideaThe Sea lilies or crinoidea

And finally, the sea cucumbers or And finally, the sea cucumbers or holothuroideaholothuroidea

We have finished this presentation but now you can find…We have finished this presentation but now you can find…

The Sea AdventureThe Sea Adventure