Crayfish are arthropods belonging to the class Crustacea. They have a hard exoskeleton made of chitin, a segmented body, and appendages including antennae, antennaules, mandibles, maxillae, maxillipeds, chelipeds, walking legs, swimmerets, uropods, and a telson. Crayfish have an open circulatory system with a heart and hemolymph but no veins. They have compound eyes, a ventral nerve cord, and can autotomize and regenerate limbs to escape predators.

1. CRAYFISH DISSECTION

4. Animal Groups Image from: http://ology.amnh.org/biodiversity/treeoflife/pages/graph.html

5. ARTHROPODA “ Arthro” = jointed “ pod” = foot

6. Arthropods

7. Structures to identify in lab All terns in the powerpoint that are printed in RED .

8. Classifying Crayfish Kingdom: ANIMALIA Phylum: ARTHROPODA Class: CRUSTACEA

9. EXOSKELETON- Outside body; NON-LIVING Made of CHITIN (polysaccharide with some nitrogen)

10. All animals with an EXOSKELETON must MOLT (shed their exoskeleton) to grow bigger

11. SEGMENTED BODY like earthworms

12. Fusion of smaller segments to make one bigger section Head + thorax = cephalothorax

13. CARAPACE Part of exoskeleton that covers the cephalothorax

14. CHELIPED = Pincher (defense; capture food) ROSTRUM = “visor” protects eyes

15. COMPOUND EYE HAS MULTIPLE LENSES

16. ANTENNAE - touch, taste ANTENNULES - touch, taste, & equilibrium

17. Statocyst

18. DECAPODS (10 legs) (4 pair walking legs + 2 chelipeds)

19. SWIMMERETS (5 pair)

20. SWIMMERETS Aid in reproduction In males – transfer sperm In females – carry eggs/young Create water currents

21. Telson Uropods Telson Uropods Uropods

22. MAXILLA – Manipulate food

23. LAST PAIR of MAXILLA = “BAILERS” Keep water moving over gills

24. MANDIBLE

25. Appendages Walking legs Cheliped 3. Maxillipeds 4. 2 nd maxilla (gill bailer) 5. 1 st maxilla 6. Mandible 7. Antenna Antennule

26. APPENDAGES ANTENNA Touch, taste ANTENNULE Touch, taste, equilibrium MANDIBLE Chew food MAXILLA Manipulate food Last pair “bailers”- Move water over gills MAXILLIPEDS Touch, taste, manipulate food CHELIPED Capture food, defense WALKING LEGS Locomotion, move water over gills SWIMMERETS Move water over EGGS, transfer sperm (males) carry young/eggs (females) UROPOD Propulsion during tailflips

27. Is it a MALE OR FEMALE? MALES : first two pair of swimmerets form a channel to transfer sperm to female seminal receptacle

28. SWIMMERETS MALES Top pair make a “ V”

29. Females “ in berry ” carry developing embryos on swimmerets

30. REPRODUCTIVE SEPARATE SEXES Male and Female EXTERNAL FERTILIZATION sperm & eggs join outside body INDIRECT DEVELOPMENT Starts as a larva

31. INDIRECT DEVELOPMENT MOLLUSKS ECHINODERMS CRUSTACEANS TROCHOPHORE BIPINNARIA NAUPLIUS

32. Examine the inside of your crayfish

33. GILLS (#2) RESPIRATORY Exchange gases Remove nitrogen waste (AMMONIA)

35. What keeps water moving over gills? “ BAILERS” WALKING LEGS: are attached to gills so walking moves water Image from: http://www.aa.psu.edu/div/mns/biology/crayfish/crayfishtable.htm

36. INTERNAL Heart Stomach Digestive gland

37. OPEN CIRCULATORY SYSTEM HEART with openings (OSTIA) ARTERIES leaving heart but NO VEINS to return hemolymph

38. OSTIA

39. ADDUCTOR MUSCLES run mouthparts

40. PYLORIC CARDIAC STOMACH

41. GASTRIC MILL “teeth” inside stomach

42. DIGESTIVE GLAND Makes bile; finishes digestion; absorbs nutrients

43. GONADS (produces sex cells)

44. Females: OVARIES – make eggs SEMINAL RECEPTACLES - store received sperm Males: TESTES – make sperm VAS DEFERENS- tubules inside that carry sperm from testes to exit opening ENDOCRINE SYSTEM: controls sexual development Also: molting, heart rate

45. ABDOMEN INTESTINE (#4) – finish digestion; absorb nutrients; collect & remove feces

46. GREEN GLANDS (#2) - collect and remove excess water & nitrogen waste (ammonia, NH 3 )

47. NERVOUS SYSTEM like earthworms VENRAL NERVE CORD CEREBRAL GANGLIA (brain) GANGLIA along body

48. VENTRAL NERVE CORD

49. CEREBRAL GANGLIA = BRAIN Nerves connect the eyes, antennae, and antennules to the brain.

50. Brain Brain

51. AUTOTOMY & REGENERATION Crayfish have the ability to “self amputate” parts to escape predators and regenerate to repair injuries

52. THE END