Life Cycle of a Bird
Lesson 1Most animals come from eggs. The eggs are produced by the adult female. Many eggs contain everything needed to form a new animal. Many eggs have a shell or outer covering. The covering keeps the egg from drying out. It also protects the new animal growing inside. Bird eggs have a hard shell. When the animal has grown enough, it breaks out of the egg. This is called hatching. Here you can see how a chicken hatches.
The new chick quickly grows into an adult. The adult female can then lay eggs and the cycle continues.
Student Activity for Lesson 1Obtain one hard-boiled egg and one uncooked chicken egg. The hard-boiled egg should not have developed a crack while cooking. Open the uncooked egg carefully (don't break yolk) and place it in a petri dish.
A. Carefully crack the shell of a hard-boiled egg. Peel the egg. Notice the dent at the end. Between this dent and the shell was an air space.
- Use a hand lens to examine the shell and its lining.
- Use a plastic knife to cut the hard-boiled egg open and observe the inside of the egg. Notice the white and yolk of the egg.
- Observe the uncooked egg in the petri dish.
- Find the twisted strands of egg white.
- Find the white spot on the yolk. The white spot is the part that may grow to be a chicken.
- Draw a picture of your findings and label the parts of an egg.
Life Cycle of a Turtle
Lesson 2Turtles, like most other reptiles, lay eggs. The turtle eggs have a softer shell that feels like leather. When the baby turtle has grown enough, it hatches. Newly hatched turtles look very much like the adult. The young turtle quickly grows into an adult. The adult female lays the eggs and the cycle continues.
Life Cycle of a Frog
Lesson 3Many young animals look much like their parents. Others do not. In each stage of growth they become more like their parents. Look at the pictures and notice how the frog changes in each stage of growth.
The frog’s eggs are laid in water. The eggs have a jellylike covering and look like a mass of jelly in the water. Young frogs hatch from the eggs.A young frog, which looks like a small fish, is called a tadpole. Like fish, tadpoles have tails and breathe air from the water in which they live.
Gradually back and front legs form. The tail disappears. Finally lungs form in the young frog. It can no longer breathe in water. It must breathe in the air. The frog is then an adult. The adult female can lay eggs and the life cycle continues.
Life Cycle of a Grasshopper
Lesson 4The grasshopper has three stages of growth. The grasshopper, an insect, begins its life cycle in an egg. After hatching, the young insect is called a nymph. A nymph is like a tiny adult, but it does not have wings. The nymph becomes an adult insect when it has wings and can fly. The adult female grasshopper can lay eggs and the cycle begins again.
Life Cycle of a Butterfly
Lesson 5Many insects, such as the butterfly, go through four stages of growth. The egg is the first stage of growth. Insect eggs may be laid almost anywhere. Often they are on leaves or other food the insects can eat after they hatch.
After hatching, the young insect is called a larva. A larva is the second stage of growth. A larva is always hungry.
After a certain time, a larva stops eating. Then it makes a covering for itself. The covering is usually hard. Now the insect is called a pupa. A pupa is the third stage of growth.
Inside the covering, the pupa slowly changes. When the changes are complete, the adult insect comes out. This is the fourth stage of growth. Now the insect looks the same as other adults of its kind. The adult female can lay eggs and the cycle begins again.
Life Cycle of a Fish
Lesson 6Most fish grow in eggs outside the mother's body. The parents usually do not protect the soft covered eggs. Many eggs are produced so that enough young survive to continue the species. When the eggs hatch the young look very much like the adult. The adult is the final stage of growth. The adult female can lay eggs to continue the life cycle.
Life Cycles of Mammals
Lesson 7Most mammals do not hatch from eggs. The animal grows in a special way in the female's body. Then they are born live. When the young are born, the mother produces milk to feed them. The babies need a lot of care. The young mammal then grows to be an adult. The adult female can produce a young animal that looks very much like itself. The animal's life cycle is then complete.
Identify stages of growth of various animals.Procedure:
Draw and label the stages in the life cycle of an assigned animal: (examples: grasshopper, butterfly, goldfinch, frog, elephant). Cut into individual stages the completed drawing of each animal's life cycle. Put all pictures in a bag. Have each student take a picture out of the bag. Each student should then find the other students who have drawings from the life cycle of the same animals. The groups that form should reassemble the order of the drawings to illustrate the life cycles of the animals. The groups should share their completed life cycles.