Compare and contrast characteristics of amphibians and reptiles. Include morphological structures, differences in reproduction, respiration, circulation, and their habitats.

Concepts to Consider: Most amphibians are tetrapods, and many have tails; the skin of amphibians is moist and participates in gas exchange, whereas reptiles rely on lungs; many amphibians lay eggs in water, and larvae known as tadpoles are free-swimming; reptiles lay amniotic eggs; amphibians have a three-chambered heart, and some reptiles have a four-chambered heart (the remainder have three chambers); because of their reproductive habits, most amphibians must return to water to lay eggs; reptiles typically bury their shelled eggs and may thrive in arid habitats. Many amphibians undergo metamorphosis during development but reptiles do not.