1. Chapter 36
Section 1
Arthropoda

2. Characteristics Lobsters, crabs, crayfish, spiders, & insects
Arthropods- members of the Phylum Arthropoda
Segmented animals with appendages- such as legs & antennae
Arthropod means “jointed foot

3. Characteristics Exoskeleton- protection & support
3 layers of exoskeleton
Outer- waxy/protein- prevents water loss and drying out
Middle- protection layer made of protein & chitin- tough carbohydrate
Inner-flexible/muscles-movement

4. Characteristics
Cephalization- brain/sensory structures located at anterior end
Appendages around mouth to aid with feeding
Antennae specialized for detecting chemicals

5. Characteristics Open circulatory system
Compound eyes- eyes made of many individual light detectors with lenses

6. Molting Molting- shedding of the exoskeleton to grow
Hormones trigger molting
Arthropods usually hide during this stage because they are vulnerable to predators

9. Evolution & Classification
Trilobites- ancient & extinct arthropod
Tagma- specialized for feeding, locomotion, & reproduction
Two major mouthparts: mandibles- jaw-like chelicerae- pincer-like

11. REVIEW!!! Name three characteristics of arthropods.
Why do arthropods molt?

12. Section 2 Subphylum Crustacea
Chapter 36
Section 2
Subphylum Crustacea

13. Characteristics Two-pairs of antennae Mandibles
Pill bugs, lobster, crayfish
Nauplius- free-swimming larva stage

14. Diversity of Crustaceans
Range of sizes, but most are small
Copepods- no larger than a comma ( , )
Japanese spider crab- 13 feet

16. Aquatic Crustaceans Copepods- marine (plankton)
Water fleas (Daphnia)- freshwater
Barnacles- marine- sessile; attach to many different surfaces
Cirri- appendages that sweep food particles into barnacle’s mouth

17. Terrestrial Crustaceans
Isopods- pill or potato bug
Lose water quickly through thin exoskeleton
Live in moist environments
Roll into a ball when threatened as a defense
Feed on decaying vegetation

18. Crayfish Freshwater crustacean Similar to lobster
Well-studied because of abundance
Decapods- crayfish, lobster, crab, & shrimp (10-feet)

19. External Structure
Body divided into abdomen & cephalothorax- consists of head & thorax- eight segments & lies behind head
Carapace- dorsal exoskeleton
Abdomen- six segments behind cephalothorax

20. External Structure Two pairs of antennae- touch & taste
Antennules- touch, taste, balance
Mandibles- chew food
Maxillae- manipulate food & draw water over gills
Maxillipeds- manipulate food

21. External Structure Cheliped- capture food & pincer defense
Swimmeret- creating water current & transferring sperm
Telson & uropods- paddle-like tail
Move in backward movement called “tail flip”

23. Digestion
Esophagus  stomach  teeth-like structures in stomach grind food to fine paste  mixed with enzymes secreted by digestive gland  enters intestine for digestion & absorption  anus

25. Respiration Feather-like gills for respiration
As crayfish walk, circulate water over gills

26. Circulation Open-circulatory system Circulatory fluid called hemolymph
Exchanges carbon dioxide with oxygen in water
Gills  dorsal part of crayfish  heart

27. Excretion Green glands- excess water, along with wastes is eliminated
Waste from green glands leaves through a pore at the base of the antennae

29. Neural Control Ganglia Controls mandibles, maxillae, & maxillipeds
Ventral nerve cord runs from the ganglia into the thorax & abdomen

31. Sensory Organs
Sense vibrations & chemicals by sensory hairs over entire body
Compound eye sense light

32. REVIEW!!!
Name three appendages of the crayfish and the function of each appendage.
How do crayfish digest food?
How do crayfish sense their environment?