1. End Show Slide 1 of 47 Copyright Pearson Prentice Hall Biology Chapter 25 - Early Tetrapods and Amphibians

2. End Show Slide 2 of 47 Copyright Pearson Prentice Hall Amphibians - first land animals Animals that have gills and lungs during their life cycle… “transition animals” - From Water to Land Movement from water to land is perhaps the most dramatic event in animal evolution evolution

3. End Show 30-3 Amphibians Slide 3 of 47 Copyright Pearson Prentice Hall What Is an Amphibian? An amphibian is a vertebrate that, with some exceptions: lives in water as a larva and on land as an adult breathes with lungs as an adult has moist skin that contains mucous glands lacks scales and claws Ch. 25- Amphibians

4. End Show 30-3 Amphibians Slide 4 of 47 Copyright Pearson Prentice Hall Evolution of Amphibians How are amphibians adapted for life on land? How have they evolved? Ch. 25- Amphibians

5. End Show 30-3 Amphibians Slide 5 of 47 Copyright Pearson Prentice Hall Evolution of Amphibians Lobe-finned fishes (lungfish) are the sister group to tetrapods Differences in the Tetrapods: Have stronger backbone Muscles to support the body in air Muscles to elevate the head Stronger shoulder and hip girdles More protective rib cage Modified ear structure to detect airborne sounds Foreshortening of skull Longer snout Ch. 25- Amphibians

6. End Show 30-3 Amphibians Slide 6 of 47 Copyright Pearson Prentice Hall Evolution of Amphibians The first amphibians appeared about 360 million years ago. The transition from water to land required that the terrestrial vertebrates had to: breathe air protect themselves and their eggs from drying out support themselves against the pull of gravity Vascular plants, pulmonate snails, and tracheate arthropods made transition earlier Amphibians only living vertebrates that have a transition from water to land in their development Ch. 25- Amphibians

7. End Show 30-3 Amphibians Slide 7 of 47 Copyright Pearson Prentice Hall Evolution of Amphibians Early amphibians evolved several adaptations that helped them live at least part of their lives out of water. Bones in the limbs and limb girdles of amphibians became stronger, permitting more efficient movement. REASONS for Adapatations: Air is 1000 times less dense Provides less buoyancy than water Provides less buoyancy than water Limbs and skeleton must support more weight Limbs and skeleton must support more weight Air fluctuates in temperature more rapidly than water Animals must adjust to these extremes Animals must adjust to these extremes Ch. 25- Amphibians

8. End Show 30-3 Amphibians Slide 8 of 47 Copyright Pearson Prentice Hall Evolution of Amphibians Ch. 25- Amphibians Showing evolutionary link to fossil record. “Missing Link” organanism from water (fish) to land (tetrapods).

9. End Show 30-3 Amphibians Slide 9 of 47 Copyright Pearson Prentice Hall Evolution of Amphibians Lungs and breathing tubes enabled amphibians to breathe air. The sternum formed a bony shield to support and protect internal organs, especially the lungs. Ch. 25- Amphibians

10. End Show 30-3 Amphibians Slide 10 of 47 Copyright Pearson Prentice Hall Evolution of Amphibians Amphibian Adaptations Pelvic Girdle Lungs 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. Ch. 25- Amphibians

11. End Show 30-3 Amphibians Slide 11 of 47 Copyright Pearson Prentice Hall Evolution of Amphibians In many adult amphibians, the internal surfaces of the lungs are richly supplied with blood vessels and folds that increase surface area. Lungs Ch. 25- Amphibians

12. End Show 30-3 Amphibians Slide 12 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians The class Amphibia is relatively small and diverse. Ch. 25- Amphibians

13. End Show 30-3 Amphibians Slide 13 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Feeding Tadpoles are typically filter feeders or herbivores that graze on algae. Their intestines help break down hard-to-digest plant material and are usually filled with food. The feeding apparatus and digestive tract of adults are meat-eating structures. Ch. 25- Amphibians

14. End Show 30-3 Amphibians Slide 14 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Frog Anatomy Ch. 25- Amphibians

15. End Show 30-3 Amphibians Slide 15 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Adult amphibians are almost entirely carnivorous. Many salamanders and frogs have long, sticky tongues specialized to capture insects. Ch. 25- Amphibians

16. End Show 30-3 Amphibians Slide 16 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians In a frog’s digestive system, food slides down the esophagus into the stomach. Stomach Esophagus Mouth Ch. 25- Amphibians

17. End Show 30-3 Amphibians Slide 17 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians The breakdown of food begins in the stomach and continues in the small intestine. Stomach Small intestine Ch. 25- Amphibians

18. End Show 30-3 Amphibians Slide 18 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians The liver, pancreas, and gallbladder secrete substances that aid in digestion. Gallbladder Liver Pancreas Ch. 25- Amphibians

19. End Show 30-3 Amphibians Slide 19 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians At the end of the large intestine is a muscular cavity called the cloaca, through which digestive wastes, urine, and eggs or sperm leave the body. Cloaca Large intestine (colon) Ch. 25- Amphibians

20. End Show 30-3 Amphibians Slide 20 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Respiration In most larval amphibians, gas exchange occurs through the skin and the gills. Adult amphibians typically respire using lungs, but some gas exchange occurs through the skin and the lining of the mouth.SKIN: Thin skin loses water rapidly Restricts terrestrial forms to moist habitats Ectotherms Body temperature depends on environment and restricts range Ch. 25- Amphibians

21. End Show 30-3 Amphibians Slide 21 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Circulation In frogs and other adult amphibians, the circulatory system forms a double loop. The first loop carries oxygen-poor blood from the heart to the lungs and skin, and takes oxygen-rich blood from the lungs and skin back to the heart. Ch. 25- Amphibians

22. End Show 30-3 Amphibians Slide 22 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians The second loop transports oxygen-rich blood from the heart to the rest of the body, and carries oxygen- poor blood from the body back to the heart. Ch. 25- Amphibians

23. End Show 30-3 Amphibians Slide 23 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Amphibian Circulation and Excretion Heart Lung Kidney Ureter Cloaca Urinary bladder Ch. 25- Amphibians

24. End Show 30-3 Amphibians Slide 24 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians The amphibian heart has three separate chambers: left atrium right atrium ventricle Ch. 25- Amphibians

25. End Show 30-3 Amphibians Slide 25 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Amphibian Heart Right atrium Left atrium Ventricle From Body To body, lungs and skin From Lungs Ch. 25- Amphibians

26. End Show 30-3 Amphibians Slide 26 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Excretion Amphibians have kidneys that filter wastes from the blood. Urine travels through tubes called ureters into the cloaca. Urine is then passed directly to the outside, or temporarily stored in a small urinary bladder just above the cloaca. Ch. 25- Amphibians

27. End Show 30-3 Amphibians Slide 27 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Reproduction In most species of amphibians, the female lays eggs in water, then the male fertilizes them externally. In a few species, including most salamanders, eggs are fertilized internally. After fertilization, frog eggs are encased in a sticky, transparent jelly. Ch. 25- Amphibians

28. End Show 30-3 Amphibians Slide 28 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians The jelly attaches the egg mass to underwater plants and makes the eggs difficult for predators to grasp. The yolks of the eggs nourish the embryos. Most amphibians abandon their eggs after they lay them. A few amphibians take care of both eggs and young. Ch. 25- Amphibians

29. End Show 30-3 Amphibians Slide 29 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Frog Metamorphosis Adult Frog Young Frog Fertilized eggs Tadpoles Ch. 25- Amphibians

30. End Show 30-3 Amphibians Slide 30 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Adults are typically ready to breed in about one to two years. Frog eggs are laid in water and undergo external fertilization. Ch. 25- Amphibians

31. End Show 30-3 Amphibians Slide 31 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians The fertilized eggs hatch into tadpoles a few days to several weeks later. Fertilized eggs Ch. 25- Amphibians

32. End Show 30-3 Amphibians Slide 32 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Tadpoles gradually grow limbs, lose their tails and gills, and become meat-eaters as they develop into terrestrial adults. Young frog Tadpole Ch. 25- Amphibians

33. End Show 30-3 Amphibians Slide 33 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Movement Amphibian larvae move by wiggling their bodies and using a flattened tail for propulsion. Adult salamanders walk or run. Frogs and toads, have well-developed hind limbs that enable them to jump long distances. Ch. 25- Amphibians

34. End Show 30-3 Amphibians Slide 34 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Response Amphibians have well-developed nervous and sensory systems. An amphibian's eyes are protected from damage and kept moist by a transparent nictitating membrane. This membrane is located inside the regular eyelid and can be closed over the eye. Ch. 25- Amphibians

35. End Show 30-3 Amphibians Slide 35 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Amphibians hear through tympanic membranes, or eardrums, located on each side of the head. Many amphibian larvae and adults have lateral line systems that detect water movement. Ch. 25- Amphibians

36. End Show 30-3 Amphibians Slide 36 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Frog’s Sense Organs Ch. 25- Amphibians

37. End Show 30-3 Amphibians Slide 37 of 47 Copyright Pearson Prentice Hall Groups of Amphibians What are the main groups of living amphibians? Ch. 25- Amphibians

38. End Show 30-3 Amphibians Slide 38 of 47 Copyright Pearson Prentice Hall Groups of Amphibians The three groups of amphibians alive today are: Salamanders (Order Urodela) frogs and toads (Order Anura) Caecilians (Order Gymnophiona) Ch. 25- Amphibians

39. End Show 30-3 Amphibians Slide 39 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Salamanders - Order Caudata (Urodela) Salamanders and newts have long bodies and tails. Most have four legs, @ right angles to body. Respiration can occur through salamander skin, and lungs Both adults and larvae are carnivores. Adults usually live in moist woods, where they tunnel under rocks and rotting logs. Internal Fertilization: Female recovers in cloaca a spermatophore deposited on a leaf or stick Ch. 25- Amphibians

40. End Show 30-3 Amphibians Slide 40 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Ch. 25- Amphibians

41. End Show 30-3 Amphibians Slide 41 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Ch. 25- Amphibians Red-Spotted Newt: Aquatic larva metamorphoses into red-eft, which remains on land for 1-3 years, until becoming secondary aquatic adult. Larval Salamander

42. End Show 30-3 Amphibians Slide 42 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Ch. 25- Amphibians Salamanders and Paedomorphosis Salamanders and Paedomorphosis Descendants retain into adulthood features that were present in larval stages of ancestors 2 species of salamanders that exhibit paedomorphosis. They both have their gills during their life cycle.

43. End Show 30-3 Amphibians Slide 43 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Frogs and Toads - Order Anura (Salientia) All have a tailed larval stage and tailless, jumping adults (except for 1 species - Ascaphus) Frogs and toads have the ability to jump. Toads have thicker skin, covered in “warty” projection glands that secrete poison. The poison is only harmuful if swallowed or gets in your eyes. Must live near water source Reproduction mode requires water Skin is water-permeable skin Ch. 25- Amphibians Coastal Tailed Frog

44. End Show 30-3 Amphibians Slide 44 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Ch. 25- Amphibians 44 families of frogs and toads 44 families of frogs and toads Family Ranidae Family Ranidae common larger frogs common larger frogs in North America in North America Family Hylidae Family Hylidae Includes the tree frogs Includes the tree frogs Family Bufonidae (toads) Family Bufonidae (toads) Contains toads with Contains toads with thicker skins and prominent warts Frogs Toad Conraua goliath- Largest frog Tree Frog

45. End Show 30-3 Amphibians Slide 45 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Ch. 25- Amphibians African Clawed Frog - has been introduced to California, and is now a huge pest. Aggressive and has caused a decline in native frogs. Similar to when huge toads were introduced to Australia.

46. End Show 30-3 Amphibians Slide 46 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Ch. 25- Amphibians Epidermis has two types of integumentary glands Mucous glands secrete protective waterproofing Mucous glands secrete protective waterproofing Large serous glands produce a whitish, watery poison Large serous glands produce a whitish, watery poison Dendrobatid frogs of South America secrete highly toxic skin poisons

47. End Show 30-3 Amphibians Slide 47 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Ch. 25- Amphibians Skeleton of frog: notice human similarities and differences. Feet - 5 digits, hand - 4 digits

48. End Show 30-3 Amphibians Slide 48 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Ch. 25- Amphibians Respiration in frogs: No diaphragm to help, instead use pressure within cavities. A.Force mouth down, air moves into mouth thru nostrils into mouth thru nostrils A.Force mouth up, air forced into lungs B.Mouth ventilates C.Muscles in abdominal wall and recoiling of lungs forces air out. recoiling of lungs forces air out. Most Carbon Dioxide is lost through the skin, not lungs. Vocal cord more developed in males.

49. End Show 30-3 Amphibians Slide 49 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Caecilians - Order Gymnophiona Caecilians are legless animals that live in water or burrow in moist soil or sediment. Caecilians feed on small invertebrates such as termites. Found in S.America, Africa, India Have vertebrae and long ribs. Many have fishlike scales embedded in their skin. Internal Fertilization. Most Oviparous, although some viviparous (young feed on walls of oviduct). Ch. 25- Amphibians

50. End Show 30-3 Amphibians Slide 50 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Ch. 25- Amphibians Female coiled around eggs Pink headed caecilian- W.Africa

51. End Show - or - Continue to: Click to Launch: Slide 51 of 47 Copyright Pearson Prentice Hall 30-3 Ch. 25- Amphibians

52. End Show Slide 52 of 47 Copyright Pearson Prentice Hall 30-3 The word amphibian refers to the ability to a.live in hot climates. b.live in wet places. c.live both in water and on land. d.live in cold and hot climates. Ch. 25- Amphibians

53. End Show Slide 53 of 47 Copyright Pearson Prentice Hall 30-3 Amphibians that maintain their ancestral larval forms throughout life (paedomorphosis) are a.Caecilians b.Mud Puppies c.Salamanders d.Toads Ch. 25- Amphibians

54. End Show Slide 54 of 47 Copyright Pearson Prentice Hall 30-3 In a larval amphibians, gas exchange occurs through a.both the lungs and the skin. b.both the skin and the gills. c.the gills only. d.in a lung. Ch. 25- Amphibians

55. End Show Slide 55 of 47 Copyright Pearson Prentice Hall 30-3 The tympanic membrane in a frog enables it to a.hear. b.see. c.smell. d.taste. Ch. 25- Amphibians

56. End Show Slide 56 of 47 Copyright Pearson Prentice Hall 30-3 Which of the following is the order for salamanders? a.Anura b.Apoda c.Caudata d.Caecilians Ch. 25- Amphibians

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