Class Amphibia
Life
History
•Amphibians were the first vertebrates to colonize
land.
•They evolved from their aquatic ancestors 350 million
years ago.
The
term “amphibian” means “double life” and refers to the biphasic life cycle which is attributed to this class.
•The first stage is the aquatic larva, or tadpole.
•The second stage is the terrestrial form or second phase
of the life cycle.
•In general, amphibians are regarded as requiring both
land and water.
