Grades K–2 · Organisms
How does a tadpole become a frog?
Many frogs begin life as eggs in water. A tadpole hatches with a swimming tail and no legs. It uses gills to take oxygen from the water.
In the diagramOne growing animal changes its bodyeggtadpolelegs growyoung frog
As it grows, its body changes. Legs develop, lungs become useful for breathing air, and the tail becomes smaller as its material is taken back into the body. These changes happen over time.
The young frog can move in new ways and use different places. It has not climbed out of its body like a costume. One living animal has developed a different body shape as it grows.
About this explanation
Starting knowledge: Recognize a tadpole with a tail and an adult frog with legs.
Sources
- National Park Service — Cascades Frog