Frog.
Frogs are an ancient group, the earliest known fossils of frogs date from the
Jurassic Period (208 million to 144 million years ago).
Amphibians are among the oldest creatures on earth.
The earliest amphibian evolved from a prehistoric fish about 350 million years ago
and became the first vertebrate (an animal with a backbone) to walk on land.
Today most scientists believe that amphibian populations are disappearing or declining at a disturbing pace.