Vertebraes

I. Class Amphibia
All of the classes of vertebrates that we have examined so far are aquatic. The next class that we will discuss is the Amphibia (both + life). As the name Amphibia suggests, amphibians have a dual life characterized by an aquatic larval stage and a terrestrial adult stage. Modern amphibians are included in Lissamphibia, which is divided into Anura (frogs), Urodela (salamanders and newts), and Gymnophiona (caecilians).
II. Challenges of Life on Land
Amphibians were the first vertebrates to adapt to the challenges of life on land. Life on land presents different problems than life in the water and amphibians exhibit a series of modifications that allow them to meet the challenges of life on land.
Aquatic versus Terrestrial Environments. The basic difference between life on land versus life in the water stems from the much greater density of water than air. Water is approximately 1000X more dense than air. Why is the difference between an aquatic medium and air impo...