ANIMAL KINGDOM CLASSIFICATION Animals can be grouped into two large categories: Vertebrates and Invertebrates. Vertebrates have backbones and invertebrates DO NOT.

 95% of all animals are invertebrates! The major phyla of invertebrates are:  Phylum Porifera  Phylum Cnidaria  Phylum Platyhelminthes  Phylum Nematoda  Phylum Mollusca  Phylum Annelida  Phylum Arthropoda  Phylum Echinodermata Invertebrates

 These are the simplest invertebrates.  All sponges are asymmetric  They have no tissues, organs or organ systems.  They just have specialized cells.  They all live in water. Porifera

 Cnidarians do not have organs or organ systems.  They have radial symmetry.  They have a single body opening surrounded by tentacles.  They have simple tissue to carry out body functions.  They have specialized cells to capture food. Cnidarians

 Radial symmetry  Hard plates embedded in the skin  Live only in oceans  Complete digestive systems  Tube feet  Include sea stars, sea cucumbers and sea urchins Echinoderms

 They have bilateral symmetry  They have nerve, muscle and digestive tissues  They have a simple brain  They have soft, flattened bodies  Have a mouth  Most are parasites. Platyhelminthes

 Roundworms  Bilateral symmetry  Nerve muscle and digestive tissues  Simple brain  Round bodies with mouth and anus Nematoda

 Bilateral symmetry  Soft bodies  Some have hard shells  Digestive system with two openings  Body cavity with heart, stomach and other organs.  Eyes and a simple brain  Must remain wet Mollusks

 Bilateral symmetry  Soft bodies  Circulatory system  Simple brains  Includes earthworms, leeches, etc. Annelids

Arthropods  Includes insects, spiders, shrimp, crab and relatives  Insects, arachnids and crustaceans  Bilateral symmetry  Exoskeletons  Jointed appendages