1. Invertebrates Invertebrates are animals without a backbone.
97% of all animals are invertebrates!
They are divided into different groups or phyla (plural of phylums).
Scientists look at something called symmetry to help classify invertebrates.

2. Invertebrates
Radial symmetry: body parts are arranged around in a circle around a central point (starfish).
Bilateral symmetry: have two sides that will match if you draw a line down the center of their body (lobster).
Asymetric: these animals have no definite shape at all (sponges).

3. Click on a box to learn more about that class of invertebrates!
When you are done, click the man at the bottom left of the screen to move on!
Cnidarian
Sponges
Arthropods
Mollusks
Invertebrates
Click below when you are done learning about invertebrates:
Echinoderms
Annelids
Flatworms

4. Cnidarians Have radial symmetry
Sometimes they have stinging tentacles around their mouths that they use to catch food.
Polyp
Jellyfish

5. Sponges Asymmetric bodies
They filter food out of the water as it passes through them.

6. Roundworms These outnumber every other animal on earth.
They can be predators, parasites, or decomposers.

7. Arthropods Have jointed body parts Bilateral symmetry Segmented bodies
Insects, Crustaceans and Arachnids are examples
Crustaceans
Arachnids
Insects
Butterfly
Beetle
House Fly
Tarantula
Lobster

8. Flatworms Long, flat bodies Bilateral symmetry
Most are parasites that invade other creatures and live off of them.
Planaria, tapeworms, liver flukes
Planaria
Tapeworm
Liver Flukes

9. Annelids Segmented worms Ringed segments Earthworms, leeches Earthworm

10. Mollusks Soft bodies Protective shell
Land mollusks include snails and slugs and have lungs.
Water mollusks include oysters, mussels, clams, squids, and octopuses which use gills to breathe.
Oyster
Snail
Octopus

11. Echinoderms Spiny skin Radial symmetry Thousands of tube-like feet
Sea Star, sea urchin, sand dollar, and sea cucumber.
Sand Dollar
Sea Urchin
Sea Cucumber
Starfish