Life Cycle of a Frog

From Egg to Adult

CA 2nd Grade Science Standard 2.b

Students know the sequential stages of life cycles are different for different

animals, such as butterflies, frogs, and mice.

Life Cycle or Metamorphosis

What name do we have for all the parts of an animal’s life from birth to death; different stages of life?

Life Cycle

Amphibian

What name do we have for an animal that lives both in water and on land?

Spawn (egg-mass)

Frogs tend to lay single eggs in big masses. Some frogs leave after this point, but others stick around to watch over the little ones.

Egg

Frogs lay many, many eggs because there are many dangers! Life starts right as the central yolk splits in two. It then divides into four, then eight, etc. Soon, the embryo starts to look more and more like a tadpole, getting longer and moving about in its egg.

About 6-21 days after being fertilized, the egg will hatch. Most eggs are found in calm water.

TadpoleShortly after hatching, the tadpole still feeds on the remaining yolk. The tadpole at this point consists of poorly developed gills, a mouth, and a tail. They usually will stick themselves to floating weeds or grasses in the water. Then, 7 to 10 days after the tadpole has hatched, it will begin to swim around and feed on algae.After about 4 weeks, the gills start being covered by skin, until they finally disappear. The tadpoles get tiny teeth which help them grate food turning it into soupy particles.

Tadpole with legs

After about 6 to 9 weeks, little tiny legs start to sprout. The head becomes more distinct and the body becomes longer. By now the diet may grow to include larger items like dead insects and even plants. After about 9 weeks, the tadpole looks more like a teeny frog with a really long tail. It is now well on its way to being almost full-grown!

Young frog (froglet)

By 12 weeks, the tadpole has only a teeny tail stub and looks like a small version of the adult frog. Soon, it will leave the water, only to return again to lay more eggs and start the cycle again!

Adult frog

Depending on water and food supplies, the frog usually completes the full growth cycle in 12 to 16 weeks. Some frogs that live in higher altitudes or in colder places might take a whole winter to go through the tadpole stage...others may have stages that vary from the typical tadpole-in-the-water type life cycle.

From Egg to Frog

Bibliography

Animal Profiles: Frogs. Rainbow Educational Media. 1991. unitedstreaming. 13 December 2005 <http://www.unitedstreaming.com/>