1. Amphibians

2. Characteristics of Amphibians
Vertebrate
Lives in water as larva; land as adult (some exceptions)
Breathes with lungs as adult
Moist skin with mucus glands
No scales and claws

3. Evolution of Amphibians
First amphibians during Devonian Period
Transitioned from water to land
Breathe air
Protect eggs and themselves from drying out
Support against the pull of gravity

4. Evolution Continued…
Adaptations evolved to live at least part of life out of water.
Stronger bones in limbs and limb girdles; more efficient movement
Lungs and breathing tubes
Sternum or breastbone for shield and support.

5. Lungs
Pelvic Girdle
Leg Bones: The legs of a land vertebrate must be strong enough to hold its weight.
Skin: The skin and the lining of the mouth cavity of many adult amphibians are thin and richly supplied with blood vessels. Watery mucus is secreted by glands in the skin.

6. As Adults lungs are richly supplied with blood vessels and folds that increase surface area

7. Class Amphibia Includes frogs, toads, salamanders, and caecilians.
Small and diverse class
Due to extinction of most amphibians during Permian Period (climate changes)
Low, swampy habitats disappeared

8. Feeding Tadpoles Adults Filter feeders or herbivores (algae)
Intestine breaks down hard plant material
Adults
Carnivores
Sticky tongues to capture insects

9. Respiration Gas exchange through skin and gills (larval stage)
Lungs, skin, and lining of mouth cavity (adult stage)
Lungless amphibians: thin lining of mouth cavity and skin

10. Circulation Double loop First loop
Oxygen-poor blood from heart to lungs and skin
Oxygen-rich blood from lungs and skin to left atrium
Second loop
Oxygen-rich blood from heart to rest of body
Oxygen-poor blood from body back to heart

11. Amphibian Heart Three separate chambers Left atrium Right atrium
To body, lungs and skin
From Body
From Lungs
Three separate chambers
Left atrium
Right atrium
Ventricle
Right atrium
Left atrium
Ventricle

12. Excretion Kidneys to filter wastes from blood
Urine excreted; travels from ureters to cloaca to outside or stored in urinary bladder
Heart
Lung
Kidney
Ureter
Urinary bladder
Cloaca

13. Reproduction
Females lay eggs in water; male fertilizes them externally (most amphibians)
Internal fertilization (salamanders)
After fertilization; frog eggs encased in sticky, transparent jelly
Yolk of egg nourishes embryo

14. Movement Wiggle tails; flattened tails for propulsion (larva)
Adult salamanders walk or run
Frogs and toads: well developed hind limbs (jump long distances)

15. Response Well developed nervous and sensory systems
Nictitating Membrane
Moist and transparent
Located inside regular eyelid
Can be closed over the eye
Tympanic Membrane
Eardrums located on each side
Lateral Line
Used to detect movement in water

17. Frog Digestion
Food enters the mouth  esophagus  stomach  small intestine  large intestine  cloaca
Cloaca: muscular cavity where solid waste, urine, eggs and sperm exit body
Liver, pancreas and gall bladder excrete enzymes that aid in digestion
Frog Movie

18. Mouth
Esophagus
Liver
Gallbladder
Stomach
Small intestine
Pancreas
Large intestine (colon)
Cloaca

19. Frog Reproduction Adults ready to breed in 1 to 2 years
Eggs laid in water (external fertilization)
Fertilized eggs  tadpoles (several days to few weeks)
Tadpoles gradually lose tails and gills, grow limbs.

21. Frog Metamorphosis
Adult Frog
Fertilized eggs
Young Frog
Tadpoles

22. 3 Groups of Amphibians
Salamanders
Frogs and Toads
Caecilians

23. Salamanders Long tails and bodies 4 legs Carnivorous
Live in moist woods (adults)
Tunnel under rocks and rotting logs

25. Frogs and Toads Ability to jump Long legs = lengthy jumps (Frogs)
Short legs = short hops (Toads)
Frogs closely tied to water
Toads closely tied to moist woods

27. Caecilians Legless animals that live in water or burrow in moist soil
Feed on small invertebrates (termites)
Fish-like scales embedded in their skin

29. Frog Dissection

30. External Anatomy

31. Tympanum

32. External Nares

33. Internal Nares

34. Vomerine Teeth

35. Tongue

36. Eustachian Tube

37. Maxillary Teeth

38. Dorsal Muscular Anatomy

39. 2. Pterygoideus
3. Temporalis
4. Masseter
5. Depressor mandibularis
6. Trapezius
11.Latissimus dorsi
14.External oblique
17.Gluteus
18.Piriformis
20.Vastus externus
25.Gracilis minor
26.Gastrocnemius
28.Semimembranosus
29.Biceps femoris

40. 4.Masseter
5.Depressor mandibularis
6.Dorsalis scapulae
10.Trapezius

41. 55.Depressor mandibularis
10.Trapezius

42. Ventral Muscular Anatomy

43. 7.Deltoid
9.Pectoralis major
12.Rectus abdominus
13.Linea alba
14.External oblique
30.Mylohyoid

44. 7
37.Deltoid
9.Pectoralis major
13.Linea alba
20.Rectus femoris
21.Adductor magnus
22.Sartorius
24.Gracilis major
25.Gracilis minor
26.Gastrocnemius
27.Achilles tendon
30.Mylohyoid

45. Internal Anatomy

46. Cerebellum

47. Cerebrum

48. Liver

49. Heart
2 Atria
1 Ventricle

50. Stomach

51. Large Intestine

52. Spleen

53. Gall Bladder

54. Pancreas

55. Lung

56. Kidney

57. Oviduct

58. Ovaries/ Eggs

59. Testes/ Sperm

60. Sperm Duct