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Amphibian Land Adaptations As amphibians evolved from lobe-finned fishes, they developed adaptations that helped them spend parts of their lives out of water. These included adaptations to their lungs, bones, and skin. Use the words below to identify how each adaptation helps amphibians survive on land. The first one has been done for you.

more efficient movement permits gas exchange protects internal organs

Body Part Adaptation How It Helps Survival Lungs blood vessels, folds that allows amphibians to increase surface area, breathe air breathing tubes

limb bones stronger limb and pelvic bones

chest bones development of sternum, or breastbone

Skin thin, richly supplied with blood vessels; watery mucus secreted by glands

Answer the question. Circle the correct answer. 1. For how long does an amphibian live on land? its entire life part of its life

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Frog Digestive System Adult frogs are mostly carnivorous. Their digestive systems are specialized to digest other organisms. Use the words below to label the structures in the frog’s digestive system.

large intestine pancreas stomach liver small intestine

Use the diagram to answer the question. Circle the correct answer. 1. Which is the first organ food passes through after it leaves the esophagus? pancreas stomach

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Fish and Amphibian Circulation Complete the table to compare fish and adult amphibian circulatory systems. The first one has been done for you.

Fish Adult Amphibian Structure of single loop double loop system

Organs that bring gills oxygen to blood

Number of atria one in heart

Do oxygen-poor yes and oxygen-rich blood mix in the heart?

Answer the questions. 1. How many ventricles do the hearts of amphibians and fishes have? 2. Which describes the blood that passes through a fish’s heart? Circle the correct answer. oxygen-rich oxygen-poor

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Frog Life Cycle Like most other amphibians, frogs spend part of their life cycle liv- ing in water and part living on land. Frogs use gills for respiration when they live in the water, and lungs when they live on land. Color the stages of the frog’s life cycle that are lived on land brown. Color the stages that are lived in the water blue.

Use the diagram to answer the questions. Circle the correct answer. 1. Where do frog eggs hatch into tadpoles? in the water on land 2. Which respiratory organs do adult frogs use? gills lungs

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