2. Arthropods: Arthropods constitute over 90% of the animal kingdom. ***First phylum to have joints*** The word Arthropod literally means jointed legs. ***First phylum to have joints*** invertebrates They are invertebrates (no backbone) They have true appendages.

3. Muscular-Skeletal The body is segmented, the segments usually grouped in two or three distinct regions chitin Exoskeleton made of chitin When they outgrow their exoskeleton, they molt! Molting Paired segmented appendages.

4. Digestion Tube from mouth to anus Divided into segments: the foregut, the midgut, and the hindgut

5. Nervous ganglion Anterior ganglion or brain and paired nerve cords Some have developed sensory ability

6. Circulation open circulatory system Have an open circulatory system that carries food, but not oxygen throughout its body Blood is often green since it does not carry oxygen Blood is often green since it does not carry oxygen heart The heart is a simple tube running along the back

7. Respiration gills spiracles Respiration by means of gills or book lungs and spiracles

8. Reproduction The sexes are nearly always separate Exception: barnacles (hermaphrodites) and some insects (parthenogenesis)

9. Excretion Passes waste out of its anus from the hindgut No nephridia malpighian tubules *** Instead they have malpighian tubules***

10. Symmetry Bilateral Symmetry