1. CRAYFISH DISSECTION
Image from:

2. Animal Groups
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3. ARTHROPODA
“jointed foot”
“Arthro” =
“pod” =
joint
foot

5. NAMING CRAYFISH Kingdom: Phylum: CLASS: ANIMALIA Arthropoda
“jointed foot”
CRUSTACEA
crusta = “flexible shell”

6. EXOSKELETON- Outside body; NON-LIVING
EXOSKELETON- Outside body; NON-LIVING
Made of CHITIN (polysaccharide) PROTEINS, LIPIDS, CALCIUM CARBONATE

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

8. SEGMENTED BODY like earthworms

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

10. CARAPACE Part of exoskeleton that covers the cephalothorax
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Part of exoskeleton that covers the cephalothorax

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

12. COMPOUND EYE
HAS MULTIPLE LENSES

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

14. Statocyst

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

16. SWIMMERETS (5 pair)

17. SWIMMERETS HELP with REPRODUCTION Males – transfer sperm
Females – carry eggs/young
Create water currents

18. Telson Uropods Image from:

19. MAXILLA – Manipulate food

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

21. MANDIBLE

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

23. 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

24. Is it a MALE OR FEMALE?
MALES: first two pair of swimmerets form a channel to transfer sperm to female seminal receptacle
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25. SWIMMERETS
MALES
Top pair
make a
“V”

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

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

28. INDIRECT DEVELOPMENT MOLLUSKS ECHINODERMS CRUSTACEANS TROCHOPHORE
BIPINNARIA
NAUPLIUS
 Trochophore image:
Nauplius image:
Bipinnaria image:

29. Examine the inside of your crayfish

30. GILLS RESPIRATORY Exchange gases Remove nitrogen waste (AMMONIA)
Exchange gases Remove nitrogen waste (AMMONIA)
GILLS

31. Image from: http://faculty. clintoncc. suny. edu/faculty/Michael
Protostomes/protostomes.htm

32. What keeps water moving over gills?
“BAILERS”
WALKING LEGS: are attached to gills so walking moves water
Image from:

33. INTERNAL

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

35. OSTIA Movie from: http://www.gsu.edu/~bioasx/heartbeat.html
Image from:
Movie from:

36. ADDUCTOR MUSCLES run mouthparts

37. STOMACH
PYLORIC
CARDIAC

38. GASTRIC MILL “teeth” inside stomach

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

40. GONADS

41. 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

42. ABDOMEN INTESTINE – finish digestion; absorb nutrients;
collect & remove feces

43. GREEN GLANDS - collect and remove excess water & nitrogen waste (AMMONIA)

44. NERVOUS SYSTEM like earthworms
VENRAL NERVE CORD
CEREBRAL GANGLIA
GANGLIA along body

45. VENTRAL NERVE CORD
Image by Riedell/Vanderwal © 2005

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

47. COMPOUND EYE

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

49. THE END

51. http://biog-101-104. bio. cornell
Thousands of SENSORY HAIRS project from exoskeleton over entire body sense vibrations & chemicals

52. Freshwater critters live in a HYPOTONIC environment

53. GAS EXCHANGE IN GILLS