1. Life Cycle of a Fish and a Frog

2. Fishes and frogs are two kinds of animals that have backbones
Fishes and frogs are two kinds of animals that have backbones. They are called vertebrates.
Animals with backbones
frogs
fishes

3. You have a backbone too. You can feel it in the middle of your back
You have a backbone too. You can feel it in the middle of your back. Your backbone helps you stand up straight. It also helps you move and bend.
backbones

4. Fishes and frogs are alike in another way
Fishes and frogs are alike in another way. They both lay eggs in or under water.
The eggs do not have a hard shell. They have thin coverings and are jellylike. Oxygen from the water passes easily into the egg.

5. Notice that young fish look very much like the adult
Notice that young fish look very much like the adult. In time, they will grow bigger, but their body shape will stay the same.
eggs
adult
larval fish
juvenile
fry (until 1 year old)

6. Fish get oxygen from water through their gills.

7. p. 17 Write the stages of the fish life cycle.
eggs
larval fish
fry
juvenile
adult

8. Frogs belong to a group of animals called amphibians
Frogs belong to a group of animals called amphibians. An amphibian lives part of its life in water and part on land.

9. Other examples of amphibians are toads and salamanders.

10. A frog life cycle begins with an egg.

11. The young frog that hatches from the egg is called a tadpole.

12. A tadpole has body parts for living in water
A tadpole has body parts for living in water. It has a tail for swimming. It breathes with external gills like fish do.

13. As the tadpole grows, it develops body parts for living on land
As the tadpole grows, it develops body parts for living on land. It grows legs. The tail disappears. Lungs replace gills.

14. Finally, an adult frog forms. It uses its legs to hop
Finally, an adult frog forms. It uses its legs to hop. An adult frog lays eggs in water. Some frogs reproduce many times before they die.

15. p. 19 Label the forg life cycle diagram
adult
adult
adult
eggs
tadpole
Tadpole with legs
froglet
froglet
adult

16. p. 20 Explain Does the tadpole look more
like a fish or its frog parents? Why?
It looks more like a fish because they
breathe through gills, swim in the water,
have a tail and a mouth like fish do.

17. Analyze How is the life cycle of a fish
different from the life cycle of a
frog?
The life cycle of the fish starts in the water and they live their whole lives in the water while the life cycle of the frogs start in the water but they live one part in the water and other part on land.

18. Infer Why does a frog begin its life cycle in
the water and then move onto land?
Because frogs lay the eggs in the water and when they hatch, the tadpoles breathe thorugh gills under water and they also feed on plankton in water.

19. Analyze What changes may occur in the
frog’s body before it can live on
land?
The tail disappears.
Lungs replace gills.
It grows legs.