1. Frog Dissection

3. Scientists believe other vertebrates evolved from BONY LOBE-FINNED fish

4. Scientific American; Dec 2005; Vol 293; p100-107

5. AMPHIBIAN CHARACTERISTICS
Moist, thin skin without scales
Aquatic larva changes to terrestrial adult
Feet without claws
Respiration with gills, lungs, skin, mouth
Closed 2 loop circulation
Ectothermic (cold blooded)
Eggs without shells or multicellular membranes

7. FROG ANIMALIA CHORDATA VERTEBRATA “backbone” AMPHIBIA “double life”
LATIN meaning
KINGDOM _____________
PHYLUM ____________________________
SUBPHYLUM ___________________________
CLASS _______________________________
ORDER _____________________________
ANIMALIA
CHORDATA
VERTEBRATA “backbone”
AMPHIBIA “double life”
ANURA “without a tail”

8. Thin, moist skin – no scales
Mucous glands make it “slimy”
Camouflage- for protection
Some have poison glands

9. ECTOTHERMIC “cold blooded”
Body temperature is dependent on surrounding environment

10. HIBERNATION/ ESTIVATION
FAT stored in FAT BODIES provides energy

11. Nictitating membrane

12. NO CLAWS

13. EXIT OPENINGS DIGESTIVE WASTE (feces) = _________________ ANUS
Shared EXCRETORY & REPRODUCTIVE EXIT =
_____________________________
(Urine & eggs or Urine & sperm)
ANUS
UROGENITAL PORE

14. Cloaca/Vent EXIT OPENINGS OPENING SHARED BY EXCRETORY, REPRODUCTIVE,
& DIGESTIVE =
_____________
Cloaca/Vent

15. What sex is it?

17. AMPLEXUS “firm embrace”
Sperm and egg released at same time and place
Increases chances of fertilization

18. TONGUE attached at front not back like yours!

19. Connect ears
to back of throat

20. GLOTTIS
Opening to
respiratory
GULLET
Opening to digestive

21. Incisions for dissection
Place frog with ventral side up
Make a longitudinal cut starting between the hind legs and going anteriorly to the tip of the jaw
Make lateral cuts behind front legs and in front of hind legs
First cut through the skin; repeat the incisions through the muscle layer

22. Females may have black & white eggs that need to be removed to see the other organs.

23. Pericardial membrane surrounds heart

24. Mesentery holds intestines together and supports all organs.

25. FAT BODIES
Store fat for energy during
Hibernation
Estivation
Breeding

26. PYLORIC SPHINCTER
CONTROLS passage of food from stomach
into duodenum (intestine)

27. Gall Bladder

28. STOMACH: LIVER: GALL BLADDER:
Makes acid and digestive enzymes
Starts digestion (grinds up food)
Makes bile
Stores glycogen
Stores vitamins
Processes toxins (including nitrogen wastes) for kidneys
Stores bile

29. Pancreas (enlarged)

30. PANCREAS: Makes TRYPSIN, INSULIN, GLUCAGON
TRYPSIN- breaks down proteins
INSULIN- tells cells to store glucose from
bloodstream as glycogen
GLUCAGON- tells cells to release stored
glucose to blood stream

31. Produces and stores new RBC’s and processes old worn out ones
SPLEEN
Produces and stores new RBC’s and processes old worn out ones

32. SMALL INTESTINE DUODENUM Receives trypsin and bile; finishes digestion
ILEUM
Absorbs nutrients
VILLI
Increase surface area

33. LARGE INTESTINE
Removes water from digestive waste;
concentrates feces

34. Body Systems : ___________ __________ _____________ EXCRETORY AMMONIA
___________________
Gets rid of nitrogen waste made by cells
Nitrogen waste has different chemical forms:
___________ __________ _____________
MOST TOXIC made from LEAST TOXIC
ammonia by liver needs the least water to dilute
FISH HUMANS BIRDS, REPTILES
AMPHIBIANS
EXCRETORY
AMMONIA
UREA
URIC ACID

35. ALL WASTE is NOT THE SAME!
DIGESTIVE waste-
left over from undigested food travels through digestive system
leaves through digestive system as feces
EXCRETORY waste- (Also called NITROGEN WASTE)
Made by cells from break down of proteins
travels through blood stream
Leaves through excretory system as
Ammonia
Urea
uric acid (depending on type of animal)

36. KIDNEYS- Remove nitrogen waste from blood and dilute it with water to make urine; osmoregulation
Image from:

37. URINARY BLADDER STORES URINE MADE BY KIDNEYS LARVAE (Tadpoles)
Excrete AMMONIA like fish
Adult frogs excrete
UREA to conserve water

38. CLOACA
DIGESTIVE
EXCRETORY
REPRODUCTIVE

39. LUNGS:
GAS EXCHANGE

40. BREATHING WITH LUNGS is called PULMONARY RESPIRATION

41. Larvae exchange CO2 for O2 with GILLS

42. OVARIES
Make eggs

43. Carries eggs to cloaca
Adds jelly coating

44. TESTES
MAKE SPERM

45. TESTES KIDNEY

46. AMPLEXUS “firm embrace”

47. INDIRECT DEVELOPMENT Grow legs; Lose tail 2 chambers  3 chambers
1 loop  2 loops
Breathe w/ gills  lungs & skin
Excrete ammonia  excrete urea
(gills & kidneys) (kidneys)

48. Ways tadpoles are like fish
Have a LATERAL LINE
Breathe with gills
Excrete nitrogen waste as AMMONIA (with gills & kidneys)
Have a 2 chamber heart
Have a 1 loop
circulatory system

49. HEART
3 chambered heart
Right atrium
Left atrium
Ventricle

50. TADPOLES & FISH: 2 chambered heart 1 loop system ADULT FROG:
Images from:
TADPOLES & FISH: chambered heart
1 loop system
ADULT FROG:
3 chamber heart
2 loop system

51. MOST vertebrates have nuclei in their RBC’s
MAMMALS DON’T

52. Fish/Tadpole circulation
Sinus
venosus
BODY organs   
Atrium
GILLS  
Conus
arteriosus
Ventricle 
Fish/Tadpole circulation

53. Conus arteriosus Frog circulation Sinus venosus    Body organs  
RIGHTAtrium
LEFT Atrium 
Lungs      
Conus
arteriosus 
Ventricle 
Frog circulation

54. BRAIN