End Show Slide 1 of 47 Copyright Pearson Prentice Hall Biology

End Show Slide 2 of 47 Copyright Pearson Prentice Hall 30-3 Amphibians

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

End Show 30-3 Amphibians Slide 4 of 47 Copyright Pearson Prentice Hall Evolution of Amphibians The first amphibians appeared in the late Devonian Period, 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, and support themselves against the pull of gravity.

End Show 30-3 Amphibians Slide 5 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.

End Show 30-3 Amphibians Slide 6 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.

End Show 30-3 Amphibians Slide 7 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.

End Show 30-3 Amphibians Slide 8 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians The class Amphibia is relatively small and diverse.

End Show 30-3 Amphibians Slide 9 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Frog Anatomy

End Show 30-3 Amphibians Slide 10 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

End Show 30-3 Amphibians Slide 11 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

End Show 30-3 Amphibians Slide 12 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

End Show 30-3 Amphibians Slide 13 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)

End Show 30-3 Amphibians Slide 14 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.

End Show 30-3 Amphibians Slide 15 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Amphibian Circulation and Excretion Heart Lung Kidney Ureter Cloaca Urinary bladder

End Show 30-3 Amphibians Slide 16 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Frog Metamorphosis Adult Frog Young Frog Fertilized eggs Tadpoles

End Show 30-3 Amphibians Slide 17 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.

End Show 30-3 Amphibians Slide 18 of 47 Copyright Pearson Prentice Hall Form and Function in Amphibians Frog’s Sense Organs

End Show 30-3 Amphibians Slide 19 of 47 Copyright Pearson Prentice Hall Groups of Amphibians The three groups of amphibians alive today are: salamanders frogs and toads caecilians

End Show 30-3 Amphibians Slide 20 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Salamanders Salamanders and newts have long bodies and tails. Most have four legs. Both adults and larvae are carnivores. Adults usually live in moist woods, where they tunnel under rocks and rotting logs.

End Show 30-3 Amphibians Slide 21 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Frogs and Toads Frogs and toads have the ability to jump. Frogs tend to have long legs and make lengthy jumps. Toads have relatively short legs and are limited to short hops.

End Show 30-3 Amphibians Slide 22 of 47 Copyright Pearson Prentice Hall Groups of Amphibians Caecilians Caecilians are legless animals that live in water or burrow in moist soil or sediment. Caecilians feed on small invertebrates such as termites.

End Show - or - Continue to: Click to Launch: Slide 23 of 47 Copyright Pearson Prentice Hall 30-3

End Show Slide 24 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.

End Show Slide 25 of 47 Copyright Pearson Prentice Hall 30-3 Fossil evidence indicates the first land amphibians appeared during the a.Jurassic Period. b.Devonian Period. c.Cambrian Era. d.Cretaceous Era.

End Show Slide 26 of 47 Copyright Pearson Prentice Hall 30-3 In a larval amphibian, gas exchange occurs through a.the skin only. b.both the skin and the gills. c.the gills only. d.in a lung.

End Show Slide 27 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.

End Show Slide 28 of 47 Copyright Pearson Prentice Hall 30-3 Which of the following is a group of amphibians living on the Earth today? a.crocodiles b.snakes c.salamanders d.lizards

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