1. CRAYFISH DISSECTION

4. Animal Groups
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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. Head + thorax = cephalothorax
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
Uropods
Uropods
Telson

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. 2nd maxilla (gill bailer)
5. 1st 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. RESPIRATORY
GILLS (#2)
Exchange gases Remove nitrogen waste (AMMONIA)

35. What keeps water moving over gills?
“BAILERS”
WALKING LEGS: are attached to gills so walking moves water
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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. STOMACH
PYLORIC
CARDIAC

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, NH3)

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