Biology Slide 1 of 47 Copyright Pearson Prentice

Biology Slide 1 of 47 Copyright Pearson Prentice Hall End Show

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

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

30 -3 Amphibians 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. Copyright Pearson Prentice Hall Slide 4 of 47 End Show

30 -3 Amphibians 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. Slide 5 of 47 Copyright Pearson Prentice Hall End Show

30 -3 Amphibians 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. Slide 6 of 47 Copyright Pearson Prentice Hall End Show

30 -3 Amphibians Evolution of Amphibians Amphibian Adaptations 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. Copyright Pearson Prentice Hall Slide 7 of 47 End Show

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

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

30 -3 Amphibians Form and Function in Amphibians Mouth In a frog’s digestive system, food slides down the esophagus into the stomach. Esophagus Stomach Slide 10 of 47 Copyright Pearson Prentice Hall End Show

30 -3 Amphibians Form and Function in Amphibians The breakdown of food begins in the stomach and continues in the small intestine. Small intestine Stomach Slide 11 of 47 Copyright Pearson Prentice Hall End Show

30 -3 Amphibians Form and Function in Amphibians The liver, pancreas, and gallbladder secrete substances that aid in Gallbladder digestion. Liver Pancreas Slide 12 of 47 Copyright Pearson Prentice Hall End Show

30 -3 Amphibians 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. Large intestine (colon) Cloaca Slide 13 of 47 Copyright Pearson Prentice Hall End Show

30 -3 Amphibians 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. Slide 14 of 47 Copyright Pearson Prentice Hall End Show

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

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

30 -3 Amphibians 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. Slide 17 of 47 Copyright Pearson Prentice Hall End Show

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

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

30 -3 Amphibians Groups of Amphibians 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. Slide 20 of 47 Copyright Pearson Prentice Hall End Show

30 -3 Amphibians 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. Slide 21 of 47 Copyright Pearson Prentice Hall End Show

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

30 -3 Click to Launch: Continue to: - or - Slide 23 of 47 End Show 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. Slide 24 of 47 End Show 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. Slide 25 of 47 End Show 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. Slide 26 of 47 End Show Copyright Pearson Prentice Hall

30 -3 The tympanic membrane in a frog enables it to a. hear. b. see. c. smell. d. taste. Slide 27 of 47 End Show 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 Slide 28 of 47 End Show Copyright Pearson Prentice Hall

END OF SECTION