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

18. SWIMMERETS (5 pair)

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

20. Telson
Uropods
Uropods
Uropods
Telson

21. MAXILLA – Manipulate food

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

23. MANDIBLE

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

25. 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

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

27. SWIMMERETS
MALES
Top pair
make a
“V”

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

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

30. Examine the inside of your crayfish

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

33. What keeps water moving over gills?
“BAILERS”
WALKING LEGS: are attached to gills so walking moves water
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34. INTERNAL
Heart
Stomach
Digestive gland

35. 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

42. GASTRIC MILL “teeth” inside stomach

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

47. GONADS (produces sex cells)

50. 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

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

52. GREEN GLANDS (#2) - collect and remove excess water & nitrogen waste (ammonia, NH3)

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

54. VENTRAL NERVE CORD

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

56. Brain
Brain

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

58. THE END