invertebrates over 90% of animals are invertebrates !

InvertebratesOver 90% of animals are invertebrates!

Characteristics of invertebrates• They are multicellular.• They are eukaryotes.• They are heterotrophs.• They don’t have a cell wall.• They can move.• Most are organised in a way called symmetrical. Sponges and coral are not symmetrical.• Most have nervous and muscle tissue.

Even sponges can move when they are larvae.

Symmetry

This means one can draw a line down the middle of the animal and the two sides will be similar like mirror images.

bilateral symmetry radial symmetry

Invertebrate Phyla

PoriferaAnnelidaCnidariaMolluscaEchinodermataArthropod

Common names for the phyla

Phylum Poriferasponges

The sponges we use in The bathtub can be naturally harversted or artificially made.

Found in marine environment.

The most primitive of the invertebrates.

They are mobile only in the larvae stage.

They are filter feeders.

Phylum Cnidariastinging cell animals

Found in marine environment

Have specialised stinging cells which they use to stun their prey.

Use tentacles to sweep in prey.

Phylum Annelida

Live on land as well as under water

Have muscles

Have a long, slender body

Segmented body – many body parts duplicated in each segment

Phylum Echinodermata

Found in marine environment

Needle like spines used for protection

Radial symmetry

Phylum Mollusca

Soft bodied

Most have a protective shell

Many have a muscular foot for movement

Phylum Arthropoda

Includes incredibly diverse groups such as:insects, crustaceans, spiders, scorpions, and centipedes.

bilateral symmetry, segmented bodies

each body segment bears a pair of jointed appendages

movement controlled by complex muscular system

body covered by an exoskeleton

spiders and insects are both part of the phylum Arthropoda

What’s the difference between a spider and an insect?

What’s the difference between a spider and an insect?

Spiders• body divided in 2 segments:

cephalothorax , abdomen;• 4 pairs of appendages;• 4 eyes;• no antennea

Insects:• body divided in 3 segments:

head, thorax, abdomen; • 3 pairs of appendages;• have antennea;• some have wings