1. Arthropods …..or “the most successful animals of all time”.
aka “bugs”.

2. Arthropods
Segmented bodies- evolution moved to fewer segments and more specialized
Jointed Appendages
includes legs and antennae
Exoskeleton of Chitin
Protection
conserve water
Classified by number of legs and body segments

5. Feeding
All possibilities: herbivores, carnivores, omnivores, filter feeders, bloodsuckers, …

6. Respiration Gills or Book gills- crabs, crayfish, lobster
Book lungs- layers of respiratory tissues stacked like pages of books: spiders
Tracheal Tubes- mostly terrestrial- air enters and exits spiracles (small openings).

8. Circulation Open system
Heart  arteries sinoid spaces sinus (vein) heart…

9. Excretion Terrestrial Aquatic Malpighian tubules
sac like organs that extract wastes from the blood and then add to feces or digestive wastes
Aquatic
diffusion to surrounding water

10. Response
well developed: all have brains and nervous system.

11. Movement well developed groups of muscles (needs nervous system)
opposing muscles: extenders and flexors.

12. Reproduction
Some have internal
and some have external
All lay eggs

13. Growth Molting- outgrows their exoskeletons 1. Skin glands
2. Secrete new soft skeleton
3. Pulls out of old skeleton
4. “Puffs” up to increase size and new exoskeleton hardens.

14. How are Arthropods grouped?
Classified based on number and structure of body segments and appendages, particularly mouthparts.

15. Classes of Arthropods
Crustaceans- crabs, shrimp, lobster, crayfish, barnacles
2 pair branched antennae
2 body segments
Cephalothorax
5 pairs of legs (the first pair is the claws)
Abdomen
Compound eyes
Have CaCO3 in Chitin for strength

18. Chelicerates (Arachnids)
horseshoe crabs, spiders, scorpions, ticks
2 Body segments
4 pair of legs
Mouthparts
Chelicerae - fangs: stab and paralyze prey
Pedipalps - grab prey
Book lungs or book gills