2. Characteristics Bilateral Symmetry Cephalization Coelomates (true body cavity) segmented bodies covered by a hard exoskeleton jointed appendages There are five common classes of arthropods: Crustacea, which includes crayfish lobsters and shrimp; Arachnida, which includes spiders, ticks and scorpions; Insecta, which comprises insects; and Chilopoda for centipedes and Diplopoda for millipedes.

3. More Characteristics Exoskeleton- hard outer shell/skeleton that helps to protect, support, give shape, hold in water. Composed of Chitin Appendages-arms, legs, antennae…parts that extend from the body. Can be herbivores, carnivores, omnivores, detrivores, filter feeders, or parasites.

5. Respiration How they obtain oxygen from the air or water. Terrestrial Arthropods(land dwelling)- have a network of tracheal tubes that extend thru their body. Some have more specialized ‘book lungs’ which are layers of respiratory tissue like pages in a book. Aquatic Arthropods (water dwelling)-use gills

6. Circulation How they move oxygen and remove carbon dioxide thru their body Arthropods have an Open Circulatory System (blood leaves the blood vessels at some point). Blood pumps from the Heart  Arteries  *leaves the blood vessels*  enters sinuses or cavities leading to organs  blood pools and collects  pumps back to the heart.

7. Excretion How waste is removed from the blood (nitrogenous waste) Arthropods have specialized structures called Malpighian tubules that extract waste from the blood and add them to digestive wastes. The waste is then removed through the gut (digestive tract) of the arthropod.

8. Response Most arthropods have a well-developed nervous system. All arthropods have brains. They also have a series of ganglia (nerve bundles) which help to coordinate movement of the many body segments. Many arthropods have very specialized sense organs.

9. Movement Arthropods move using well developed groups of muscles that are coordinated and controlled by the nervous system.

10. Reproduction Sexual Reproduction Terrestrial arthropods all have internal fertilization. Either the male reproductive organ places the sperm inside the female and fertilization occurs, or the male deposits sperm packets that are picked up by the females for internal fertilization. Aquatic arthropods may have internal or external fertilization. External fertilization occurs when females release their egg into the external environment and males release sperm around the eggs

11. Phylum Echinodermata

12. Characteristics No anterior and posterior end No cephalization (no head area) 2 sided bodies Spiny skin, internal skeleton Water vascular system, excretory and nervous system Suction cup like tube feet Radial symmetry Usually 5 parts

13. Water Vascular System Circulation, respiration, movement Oxygen food and wastes are circulated and carried throughout the organisms

15. Reproduction Reproduction Echinoderms reproduce by external fertilization. Sperm are produced in testes, and eggs are produced in ovaries. Sperm and eggs are deposited into open water where fertilization occurs The larvae, which have bilateral symmetry, swim around for some time and then swim to the ocean bottom, where they develop into adults that have radial symmetry.

16. Examples There are roughly 7000 species of echinoderms—all of which live in the world’s oceans Classes of echinoderms include sea urchins and sand dollars; brittle stars; sea cucumbers; sea stars; sea lilies and feather stars.