Invertebrates
Simplest invertebrates
Corals sponge's jellyfish
ocean
Earthworms
soil
Echinoderms
sea urchins' sea stars
saltwater have body parts in multiples of live
Arthropods
largest group
crustacean
spiders
insects
antennae, jaws, three body segments
two body segments, eight legs
exterior shell, five pairs of jointed limbs
more complex invertebrates
mollusks
have shells for protection
squid
have internal shell
octopi
do not have shell at all