Remember finding those little tadpoles along the water's edge when you went fishing with dad or grandpa? Those little tadpoles went from cute little "fishy things" to frogs!
The process by which frogs evolve from eggs, to tadpoles, to frogs, is called metamorphosis. Metamorphosis is a biological process that means animals change in appearance as they physically develop after birth.
Following the frog along this journey is very enlightening and can be a wonderful activity to watch if one is lucky enough to be near a place where frogs live or has somewhere to keep frogs in captivity and still allow them to reproduce.
The journey begins with the mating of a male and female frog. The female frog then lays as many as a 1000 eggs in a clump called a "frog spawn". The eggs are laid in masses and covered by a substance of jelly-like material that helps protect the eggs from predators.
Each egg matures by cell splitting activity until, inside, it begins to take the shape of a tadpole. It can take 10 - 20 days for the tadpole to emerge, or hatch, from the egg. The newly hatched tadpoles are made up of gills, a mouth, and a tail. They live off the yolk of their original egg and do not begin to swim around for 7 - 10 days.
As it begins to move about and continue on its journey, the tadpole grows hind legs and, soon after, legs in the front. Its age by now is anywhere from 9 to 12 weeks. The tails become smaller and tadpole begins to develop lungs. Instead of feeding off algae as it has been forced to do, it can, with the development of a larger tail, swim around and catch larger food. Tadpoles in this phase of maturity can eat plants, small insects, and even other tadpoles.
At about 12 - 15 weeks the tadpole looks a lot more like a frog. It's tail is nearly gone. It must surface and use its new lungs to breathe. The gills are no longer functionable. It continues its journey to adulthood and moves onto land where it will spend most of its time. It can now eat small insects and worms to survive.
As true frogdom approaches the newly evolved frog will set out to find a mate and begin the process all over again by laying, or fertilizing depending on its gender, frog eggs of its own!