1. Amphibians

2. HERPETOLOGY = the study of reptiles and amphibians

3. Class Amphibia

4. What is an amphibian? 4000+ species
AMPHIBIAN = GREEK FOR AMPHIBIOS WHICH MEANS “DOUBLE LIFE”

5. Amphibians VERTEBRATES Metamorphosis
HIBERNATE OR ESTIVATE DEPENDING ON CLIMATE
Scientist infer that amphibians evolved from lobe-finned fishes called crossopterygians.

6. Amphibian Characteristics
1st true tetrapod vertebrates Bony skeletons with four limbs Exceptions: Caecilians (limbless) and Sirens (forelimbs only) Feet are webbed and the toes lack claws. They have moist, smooth, thin skin with no scales.

7. Amphibians are ectotherms, which means their blood temperature rises and falls with that of the surrounding environment
Copyright Cmassengale

8. Respiration Larva (tadpoles) breathe with gills Adult frogs have lungs
Some amphibians keep gills all their life, mudpuppy

9. Respiration
Lungs are internal - allows exchange of oxygen and carbon dioxide between blood and air
Greater the surface area the greater the amount of oxygen can be absorbed
Lungs are not as efficient as gills, but there is more oxygen in air than in water so lungs do not have to be

10. Respiration Cutaneous respiration- “Skin breathing”
Supplement oxygen intake w/ moist skin
Limited by body size
Many terrestrial salamanders have no lungs at all  breathe through skin and mouth cavity

11. Circulation
Heart is a double loop, with 3 chambers  2 atria and a ventricle that is partly divided

12. Double Loop Circulation
Due to moving to land and requiring more oxygen for their muscles, amphibians developed a double loop in their circulatory system
Amphibians have pulmonary veins that deliver oxygen rich blood back to the heart and then to the remainder of the body

14. Larvae have two-chambered hearts; adults have three-chambered hearts and well-developed circulation.
Copyright Cmassengale

15. CLOACA
sperm, egg, solid wastes, and urine leave the body through this opening

16. Feeding Larva (tadpoles) are usually herbivores
Adults are usually carnivores
Digestive tract
Mouth  esophagus  stomach  small intestine  colon (large intestine) cloaca

17. Excretion Kidneys filter cellular (liquid) waste = urine
Kidneys  ureters  small urinary bladder  cloaca

18. Response
Well developed nerves and nervous system – complex brain with cerebrum, cerebellum, medulla oblongata
Eyes move in socket and are protected by nictitating membrane – transparent membrane that covers the eye when amphibian is in the water
Tympanic membrane = eardrums
Lateral line systems = detect water vibrations

19. Amphibians enter a state of dormancy or torpor when conditions are unfavorable. They often bury themselves in mud or leaves, emerging when conditions are better.
Copyright Cmassengale

20. Amphibian Reproduction
Require water because eggs lack shells to prevent water loss
Yolk of egg nourishes developing embryo
External Fertilization - female releases eggs and male fertilizes externally-called amplexus

21. Reproduction
Larvae commonly called tadpoles, process by which tadpoles become adults - metamorphosis
A few species care for eggs by incubating in mouth, or on their back or stomach!

22. METAMORPHOSIS
Series of changes that occur as an organism grows

23. larva  young adult adult
Amphibians have many prominent characteristics that are adaptations to a life spent both on land and in water: They change from an aquatic larval stage to a terrestrial adult form.
Eggs 
larva  young adult adult

24. Amphibian Metamorphosis
It affects nearly every organ in the tadpole’s body
Tadpoles:
Herbivorous, Aquatic, Single-loop circulation, Gills
Frogs:
Carnivorous, Terrestrial or aquatic, Double-loop circulation, Lungs

25. Amphibian Evolution
Biologist conclude that amphibians appeared during the late Devonian period, about 345 million years ago.
Copyright Cmassengale

26. Paleontologists have discovered fossils of a species that provides the missing evolutionary link between fish and the first animals that walked out of water onto land about 375 million years ago. The newly found species, Tiktaalik roseae, has a skull, a neck, ribs and parts of the limbs that are similar to four-legged animals known as tetrapods, as well as fish-like features such as a primitive jaw, fins and scales.

27. Amphibian Adaptations for Life on Land
Bones became stronger
Lungs to breath air
Limbs to walk on land
Sternum (breast bone) and ribs to protect internal

29. History Carboniferous Period = Age of Amphibians
Climate change caused habitats to disappear
3 groups survive today salamanders, frogs, and caecilians

30. Amphibian Groups Kingdom Animalia …..Phylum Chordata
……...Subphylum Vertebrata
………….Class Amphibia
Order Urodela
Order Anura
Order Apoda

32. Order Anura Means “Without a tail” Frogs and Toads
Copyright Cmassengale

33. There are about 3,500 known species of frogs and 300 kinds of toads They are found on every continent except Antarctica Frogs have smooth, moist skin Toads have dry, bumpy skin
Copyright Cmassengale

34. Some types spend their entire life in or near water, but others live mainly on land and come to the water only to mate
Copyright Cmassengale

35. Some frogs and toads are climbers that dwell in trees or burrowers that live underground.
Copyright Cmassengale

38. See videos at

39. Order Urodela Means “visible tail” Salamanders and Newts
Copyright Cmassengale

40. Copyright Cmassengale

41. Salamanders, typical members of the Order Urodela, have elongated bodies, long tails, and smooth, moist skin
Copyright Cmassengale

42. Compared to the anurans, salamanders are less able to remain on dry land, although some can live in dry areas by remaining inactive during the day
Copyright Cmassengale

43. Salamander lay their eggs in water and like anurans they hatch into swimming larva
Salamander eggs
Copyright Cmassengale

44. Other species can reproduce in damp land environments
Other species can reproduce in damp land environments. Eggs laid on land hatch into miniature adult salamanders
Marbled Salamander
Copyright Cmassengale

45. Order Apoda
Means “without feet”
Caecilians
Copyright Cmassengale

46. tropical, burrowing worm-like amphibian that is often legless
Copyright Cmassengale

47. Have fish-like scales

48. These creatures average 30 cm, but they can be up to 1.3m long.
They have very small eyes and are often blind.
They eat worms and other invertebrates

49. The caecilian male deposits sperm directly into the female, and the female bears live young

50. Amphibian Ecology Number of living species is declining
Environmental threats:
Decreasing habitat
Pollution
Fungal infections
Introduced predators
Increasing human population

51. Amphibian Habitats forests grasslands lakes, ponds, marshes
rivers and streams

52. Quick Check 1. How many chambers does the heart of a frog have? ____
2. The opposite of terrestrial is ___________
3. A series of changes that occur from birth to adulthood (tadpole → frog) is called _______________
4. Tadpoles breathe using _______.
5. The main organ of excretion is the _____________
6. Urine, eggs, and other wastes exit through the __________
7. The opposite of carnivorous is _____________
8. A caecilian is an amphibian that does not have ________
9. The study of reptiles and amphibians is ___________
10. To what kingdom do frogs belong? _________ what phylum? ____________
what class ? _____________