Mr. Ribbit, the science teacher, cleared his throat.
"Ribbit! Do you know how we became frogs?" he croaked.
The young frogs looked at each other.
Mr. Ribbit held up two pictures.
In one hand was a picture of a tadpole.
In the other was a picture of a frog.
"Today we are going to learn about metamorphosis. Ribbit!" he said.
"Meta . . . what?" asked Freddy.
"Metamorphosis," Mr. Ribbit repeated.
"It is how we change from tadpoles into frogs.
In the spring male frogs attract female frogs by singing.
The frog couple starts their family in the pond. Ribbit!
The male frog fertilizes the eggs in the water.
A few days later, the eggs begin to change."
"Do they become tadpoles?" asked Hetty.
"Ribbit! Yes. At this stage, the head is big and the tail is very long," explained Mr. Ribbit.
"Soon the eggs hatch and the tadpoles come out.
Tadpoles, like fish, use gills to breathe."
"But Mr. Ribbit, we aren't fish, are we?" asked Lily.
"Of course not! We are amphibians.
Who knows what that means?"
"Amphibians can live on land and in water," answered Boris.
"Right! But at first, tadpoles can only live in the water."
"What do tadpoles eat?" asked Freddy.
"Ribbit! As soon as they are born, tadpoles eat plants and algae.
A few days later, they develop teeth.
Then the tadpoles start to eat insects."
Mr. Ribbit continued, "Tadpoles use their tails to swim.
They are very active at this age.
Tadpoles swim around in a group called a school.
Six to nine weeks after they are born, metamorphosis begins. Ribbit!
The back legs begin to appear and the tadpoles use them for swimming.
The body grows larger, and the head begins to take shape.
Next, the front legs begin to grow."
"That looks like my brother!" Hetty laughed.
"Ribbit! It looks just like a small frog except for the long tail.
The tadpole is almost a frog now," said Mr. Ribbit.
"During the last days of metamorphosis, the tail slowly disappears into the body.
Remember the tadpoles' gills? Ribbit!
They don't need them any more.
The gills are covered over by skin.
So the little frogs learn to breathe with their lungs.
Once the tail is gone, the little ones can climb onto land.
Now the tadpole is completely transformed into a frog.
In a few days, the new frogs can leave the pond.
They can enjoy life both in the pond and on land.
Metamorphosis takes about 12 to 16 weeks.
There are many different kinds of frogs.
Some like to live in the water.
Others spend all their time on the land.
But we always have to return to the water to start our own families," concluded Mr. Ribbit.
"Wow! We are special in many ways!" Victor exclaimed.
"It's interesting to know how we got here," the young frogs croaked.
"We are proud to be frogs! Ribbit!"