1. The Life Cycle of a Frog

2. Objectives Students will be able to determine what a tadpole is.
Students will understand the metamorphoses of the frogs life.
Students will be able to describe a frog habitat.

3. Let’s have a closer look.
Today we are going to look at the life cycle of a frog. This picture shows the different stages of development.
Let’s have a closer look.

6. Metamorphosis
Metamorphosis is the changes that a frog goes through during its life cycle.
There are four main stages in the life cycle of the frog.

7. These are my babies. They are like eggs but have a special name
These are my babies. They are like eggs but have a special name. Do you know what they are called?

9. Egg The first stage in the life cycle of the frog is the egg.
A frog lays many eggs at one time.
The eggs are covered with a jellylike coating.

10. Egg Frogs are amphibians.
Amphibians can live on land and in the water.
Frogs begin their life cycle in the water.
Female frogs can lay as many as 6,000 eggs in clumps called spawn.
Each egg is a ball of jelly.
The spawn floats to the top of the pond where the water is warmer and helps the eggs to grow.

11. Egg Stage 1
This Photo by Unknown Author is licensed under CC BY-SA

12. Frog Spawn Frogs lay their eggs in water or wet places.
A floating clump of eggs is called frog spawn.
    
This large and slippery mass of eggs is too big to be eaten. 
This is nature's way of protecting them.

14. DO YOU NOTICE ANY CHANGES?

16. Look closely at the tadpoles.
What can you see?

17. Tadpole The second stage of the frog life cycle is the tadpole.
Hatched tadpoles have gills for breathing in the water.
They have a tail, but no legs.

19. Tadpole
After about 10 days the tadpole is ready to wiggle from the egg.
Tadpoles breathe through gills on the outside of their bodies for about 5 weeks.

21. Tadpole The tadpole has a long tail, and lives in the water.
It must rely on its camouflage to protect it.
The tadpoles also face danger by being eaten by other water animals. 
Sometimes a pond dries up and the tadpoles die.

24. What has happened to the tadpole?

25. Tadpole
The back legs begin to appear and its outside gills begin to disappear.
It can still breathe underwater through gills which are inside of its body.
This Photo by Unknown Author is licensed under CC BY-NC-SA

26. Tadpole
About 1 week after the legs have appeared the tadpole will begin to develop lungs and then breathes air like us.
This means he now needs to come to the surface for air.

27. As a tadpole grows, lungs begin to form.
Back and front legs begin to grow. These parts allow the adult frog to live on land.

28. Tadpole
At about 10 weeks the tadpole develops front legs and will not need to eat as it will start to absorb its tail and get food from the nutrients that are in it.

30. What is the tadpole beginning to look like?

31. Getting bigger Froglet
After about five weeks the tadpole begins to change.
It starts to grow hind legs. Behind its head, bulges appear where the front legs are growing and its tail becomes smaller. 
Lungs begin to develop, preparing the frog for its life on land.   
Froglet

32. Froglet to Frog
After about 3 ½ months the tadpole has become a froglet and is ready to eat small bugs and spend time out of the water.
The frog continues to grow, it loses its tail completely and leaves the pond. The frog will eat crickets and other insects, bugs, and worms. Frogs need to live in damp places.

33. A young frog
Over time, the tadpole becomes even more froglike.  It has shed its skin and lips. Its mouth widens, and it loses its horny jaws. The tail becomes much smaller, and the legs grow. Its lungs begin to work.

35. Adult Frog
Once the lungs form and begin to work, the gills and tail disappear.
The adult frog is now ready to live on land.

37. An adult frog
Eleven weeks after the egg was laid, a fully developed frog with lungs, legs, and no tail emerges from the water.
This frog will live mostly on land, with occasional swims. The tiny frogs begin to eat insects and worms. 
Eventually, it will find a mate. The female lays the eggs, the male fertilizes them, and the whole process begins again.

38. I hope you enjoyed the show all about my life
I hope you enjoyed the show all about my life. What things can you remember?

39. Let’s have one last look at the life cycle of a frog.

40. What is the first stage of the frog life cycle?

41. The first stage of the frog life cycle is the egg (spawn).

42. What is the second stage of the frog life cycle?

43. The second stage of
the frog life cycle
is the tadpole.

44. What is the last stage of the frog life cycle?

45. The last stage of the frog life cycle is the adult frog.

46. Animations available from www.animationfactory.com