Amphibians hic.com/animals/amphibians/a mazon-horned- frog.html?nav=DL4 hic.com/animals/amphibians/a mazon-horned- frog.html?nav=DL4 hic.com/animals/amphibians/a mazon-horned- frog.html?nav=DL4 Chapter 30-3

Have survived for millions of years Have survived for millions of years Over 4000 living species Over 4000 living species

Evolution of Amphibians First amphibians to climb onto land probably resembled the modern coelacanth. (but had legs) First amphibians to climb onto land probably resembled the modern coelacanth. (but had legs) Appeared in late Devonian Period (360mya) Appeared in late Devonian Period (360mya)

Early amphibians evolved several adaptations that helped them live atleast part of their lives out of water. Early amphibians evolved several adaptations that helped them live atleast part of their lives out of water. Bones in limbs and limb girdles became stronger Bones in limbs and limb girdles became stronger Lungs and breathing tubes enabled amphibians to breathe air. Lungs and breathing tubes enabled amphibians to breathe air. Sternum protected internal organs. Sternum protected internal organs.

Became dominant during Carboniferous Period ( mya) Became dominant during Carboniferous Period ( mya) Gave rise to ancestors of living amphibians and vertebrates that live completely on land. Gave rise to ancestors of living amphibians and vertebrates that live completely on land. Most groups became extinct by end of Permian Period (245 mya) Most groups became extinct by end of Permian Period (245 mya)

3 Surviving Orders Frogs and toads Frogs and toads Salamanders Salamanders Caecilians Caecilians

Form and Function in Amphibians Feeding: Feeding: Tadpoles: strictly herbivorous grazers Tadpoles: strictly herbivorous grazers Adults: carnivorous Adults: carnivorous *Most amphibians equipped with long sticky tongues to catch prey *Path of food: mouth  esophagus  sto mach  small intestine  large intestine  cloaca (waste leaves)

Respiration Gas exchange occurs in various ways Gas exchange occurs in various ways Tadpoles: gills and skin Tadpoles: gills and skin Adults: skin, mouth cavity, and lungs Adults: skin, mouth cavity, and lungs

Circulation Amphibian heart: 3 chambers—left atrium, right atrium, ventricle Amphibian heart: 3 chambers—left atrium, right atrium, ventricle Double loop circulatory system: Double loop circulatory system: Loop 1: Carries oxygen- poor blood from heart to lungs and skin. Loop 1: Carries oxygen- poor blood from heart to lungs and skin. Loop 2: Carries oxygen- rich blood from skin and lungs to heart. Loop 2: Carries oxygen- rich blood from skin and lungs to heart.

Excretion Kidneys filter wastes from the blood Kidneys filter wastes from the blood Urine moves through tubes called ureters into the cloaca. Urine moves through tubes called ureters into the cloaca. Urine may be temporarily stored in a small urinary bladder above the cloaca. Urine may be temporarily stored in a small urinary bladder above the cloaca.

Reproduction Amphibian eggs do not have shells and dry out if not kept moist. Amphibian eggs do not have shells and dry out if not kept moist. Female releases eggs that are fertilized by male. Female releases eggs that are fertilized by male. Salamanders: eggs fertilized internally. Salamanders: eggs fertilized internally. Eggs are released in water, yolk nourishes developing embryos Eggs are released in water, yolk nourishes developing embryos Larvae: tadpoles Larvae: tadpoles

Response Well-developed nervous and sensory systems. Well-developed nervous and sensory systems. Nictitating Membrane: protects eyes from damage underwater Nictitating Membrane: protects eyes from damage underwater Tympanic Membrane (eardrum): responds to external stimulus of sound. Tympanic Membrane (eardrum): responds to external stimulus of sound.

Groups of Amphibians Salamanders and newts: long bodies and tails. Salamanders and newts: long bodies and tails. Most have four legs. Most have four legs. Larvae and adults are carnivorous. Larvae and adults are carnivorous. Some have gills as adults and live in water. Some have gills as adults and live in water.

Frogs and Toads: Ability to jump. Frogs and Toads: Ability to jump. Frogs: longer legs than toads—better jumpers. Frogs: longer legs than toads—better jumpers. Toads: ability to live further from water. Toads: ability to live further from water. Both: lack tails. Both: lack tails.

Caecilians: legless, live in water or burrow in moist soil or sediment. Caecilians: legless, live in water or burrow in moist soil or sediment. Feed on small invertebrates (termites) Feed on small invertebrates (termites) Many have fishlike scales embedded in skin. Many have fishlike scales embedded in skin.

Ecology of Amphibians Must live near water Must live near water Skin color and markings enable them to blend with surroundings. Skin color and markings enable them to blend with surroundings. Some have skin glands that ooze toxins. Some have skin glands that ooze toxins. Populations of amphibians in decline. Populations of amphibians in decline. Due to warming trends, habitat loss, fungus, acid rain, increasing human population, invasive predators Due to warming trends, habitat loss, fungus, acid rain, increasing human population, invasive predators