1. Simple Invertebrates Sponge Sponges are asymmetrical
and do not have real tissue or organs.
Cnidarians have radial symmetry
and have a mouth, tentacles, muscle tissue and stinger cells
sponge
jellyfish
Sea anemone
coral
hydra

2. Simple Invertebrates
Flatworm -flat body, head with simple eyes, and a mouth
Roundworm-simple digestive and nervous system
Segmented worm-divided into sections and has organs such as a heart, stomach, and brain
Flatworm
Roundworm
(nematode)
Segmented worm
(annelids)

3. Complex Invertebrates -Mollusks
Snails
have bilateral symmetry
a muscular foot or tentacle
mass of internal organs
most have a shell
specialized organs including heart, gills and a well-developed nervous system
Snails
clams
squid

4. Complex Invertebrates-Echinoderms
have a hardened skeleton inside the body (endoskeleton)
usually have radial symmetry
use a water pressure system that helps them feed, breathe and move
Sea star
Sea urchin
Sea cucumber

5. Complex Invertebrates -Arthropods
crabs
hard skeleton on the outside (exoskeleton) provides strength and protection.
bilateral symmetry
segmented bodies with jointed legs
efficient nervous sytem and good sensory systems
crabs
insects
spiders