When I saw this almost prehistoric looking tadpole/frog I thought of Sean so I have to dedicate this image to him!

Frogs go through several stages of transformation before they become adult frogs. They start out as eggs and within a few days the eggs develop into tiny tadpoles. After a few weeks the tadpole's thyroid gland initiates metamorphosis. Within 24 hours the tadpole starts to transform into a frog.

Almost every organ has to change so the tadpole can go from living underwater to living on land. Next, the tadpole will grow hind legs - like the one in this image. After the hind legs start to form the front legs will begin to develop and the tail will start to disappear. The tadpoles skull is made out of cartilage but during metamorphosis the cartilage is replaced by bone so his face starts to look like a frog and his gills will disappear and the lungs will have enlarged. Now he is a froglet and ready to live on land. Once the tail disappears he will be an adult frog.