What is an Amphibian?
Definition: 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, and lacks scales and claws.
Definition: 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, and lacks scales and claws.
Body Plan:
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. Lungs and breathing tubes enabled amphibians to breathe air. The sternum, or breastbone, formed a bony shield to support and protect internal organs, especially the lungs. Feeding: Tadpoles are typically filter feeders or herbivores that feed off algae. Adults are almost entirely carnivorous. Circulation: The circulatory system forms a double loop. |
Respiration:
Breathe through gills when in larval stage and lungs when they are adults. Excretion: Wastes removed by kidneys, which are excretory organs that filter wastes from the blood. Response: They have well-developed nervous systems and sensory systems. Reproduction: Fertilized externally. |