Characteristics of Amphibians
Legs: ceacilians lost legs during adaptation to burrowing life style
Lungs: one pair of lungs, but internal surfaces still poorly developed; amphibians still breathe by movement of mouth floor
Cutaneous respiration: supplements lungs by respiring across skin
Pulmonary veins: two pulmonary veins return aerated blood to heart for re-pumping ? higher blood pressure to tissues
Partially divided heart: 2 front chambers (atrium) separated ? prevent mixing of aerated from nonaerated blood; main chamber (ventricle) not divided