1. Arthropods Chapter 13 Section 3

2. Arthropods • Jointed appendages, • Bilateral symmetry • Segmented bodies • Exoskeleton • Body cavity • Digestive system with two openings • Nervous sytsem • MOST have separate sexes (not hermaphrodites)

4. Arthropods • Some many segments, others have fused segments forming body regions • A hard, thick, outer covering called an exoskeleton covers, supports, and protects the arthropod, it is shed and replaced occasionally in a process called molting

5. Insects • 3 body regions

6. Insect body regions • An insect’s head has a pair of antennae, eyes, and a mouth • The thorax has three pairs of legs; if the insect has wings, they are attached to the thorax • The abdomen contains reproductive structures and an open circulatory system; insects obtain air and release waste gases through openings called spiracles

8. Metamorphosis • Series of body changes as insects become adults

9. Incomplete metamorphosis • Egg, nymph adult

10. Complete metamorphosis • Egg, larva, pupa, adult

11. Metamorphosis • Insects eat plants, blood of animals, nectar, decaying materials, wood, and clothes; mouth parts are diverse and adapted to diet • Insects are successful due to their exoskeletons, ability to fly, rapid reproductive cycles and small sizes

12. Arachnids • Spiders and ticks have two body regions (the cephalothorax and abdomen), four pairs of legs, and no antennae

13. Scorpions • Sharp, poison-filled stinger at the end of their abdomen

14. Spiders • Inject their prey with enzymes to digest it.

15. Mites and Ticks • Generally parasites; ticks often carry diseases

16. Centipedes and millipedes • Long bodies with many segments, many legs, antennae, and simple eyes

17. Crustaceans • Crabs, shrimp, and barnacles have one or two pairs of antennae and mandibles for crushing food

18. What arthropods can do! • Food source • Aid in agriculture, important part of ecological communities in which humans live • BAD  • Some are pests that carry disease or damage property

19. Insecticides • Can kill insects, but cause other environmental problems; biological methods for controlling insects are being developed

20. Arthropod fossils • Some fossils are more than 500 million years old • Probably evolved from a segmented worm ancestor.