Invertebrates - Lack a backbone.
Vertebrates - Have a backbone.
Asymmetry - No top or bottom and no left or right side. Uneven or lacking balance. No cut gets a mirror image.
Radial symmetry - Only a top and bottom but no left or right side. Many cuts give a mirror image.
Sessile - Does not move much.
Bilateral symmetry - Has a top and bottom and also a left and right side. Only can be cut in 1 plane and get a mirror image.
Cephalization - Animal has a brain at the head end.
*Phylum Porifera - Pore Bearing Animals. Very primitive and have no symmetry.
( Sponges )
*Phylum Cnidaria - Stinging Animals, all have radial symmetry.
( Sea Anemones, Corals, & Jellyfish )
Cnidocytes - A stinging cell
Medusa - Free-swimming - tenticles hang down
Polyp - stationary - tenticles go up
*Phylum Platyhelminthes - Flatworms - free-living or parasitic
( Flatworms, Flukes, & Tapeworms )
*Phylum Nematoda - Roundworm - free-living or parasitic, very numerous
( Roundworms - Pinworms & Hookworms )
*Phylum Mollusca - Contains the biggest invertebrate.
( Snails, Slugs, Oysters, Clams, Octopus, & Squid )
Mantle - A thin layer of tissue that makes/secretes the shell.
*Phylum Annelida - Segmented Worms
( Earthworms, Marine Worms, & Leeches )
*Phylum Arthropoda - Jointed Foot Animals - More species than any other phylum of animals
( Insects, Spiders, Crustaceans, Centipedes, & Millipedes )
Exoskeleton - hard covering outside the body made of chitin.
Chitin - Polysaccharide
Head (Antennae and eyes), Thorax (Legs and wings), and Abdomen (Internal organs)
*Phylum Echinodermata - Spiny skin animals - Radial symmetry
( Sea Stars, Sea Urchins, Sand Dollars, & Sea Cucumbers )
Last updated on 4 January 2018