1. Amphibians
The word amphibian comes fro the Greek word amphibious- meaning double life

2. Lifestyle spend part of their life on land
part of their life spent in water
ectotherms
hibernate
estivate

3. appearance smooth, moist skin no scales
thin skinned for oxygen exchange

4. heart three chambered heart one chamber receives oxygen filled blood
one chamber receives carbon dioxide filled blood
the third chamber pumps oxygen to body tissues and carbon dioxide back to the lungs

5. Reproduction depend on water for reproduction
their eggs dry out easily
external fertilization

6. Development metamorphosis fertilized eggs become a tadpole
tadpoles grow into the adult frog with legs, 3 chambered hear and lungs
In salamanders the young look just like the adults

7. Biological Indicators
Easily affected by changes in the environment
they absorb things directly through their skin making them susceptible to pollutants
Their eggs are exposed in the water and can be easily affected by pesticides