Cycles of Life
Spring is the season of new beginnings, so what better time to teach about life cycles?
- Grades: PreK–K
- Unit Plan:
Students learn about metamorphosis by watching one or more insects change from egg to larva to pupa to adult. They record the process and make a life cycle picture.
- Observe the eating habits of insect larva.
- Compare and contrast the larva and adult insect.
- Record the insect's metamorphosis.
- Sequence the life cycle of an insect.
- A picture or read-aloud book that illustrates metamorphosis. (I like to use the book The Very Hungry Caterpillar by Eric Carle.)
- Photographs (or your own drawings) of the four stages of butterfly's life cycle: egg, larva or caterpillar, pupa, adult butterfly
- Magnifying glasses, one for each student
- Live insect eggs or larva (mealworms, silkworms, caterpillars, or ladybugs work well), one or several for each student
- A cup or larva container, one for each student
- Student Recording Sheets (PDF), enough for each student to record observations on several days throughout the metamorphosis process
- White paper plates, two for each student
- Large brass brads, one for each student
- Pens, crayons, and markers
Set Up and Prepare
- Order live insect larva or eggs from commercial distributor or purchase from a pet store. Allow plenty of time for delivery, and see Directions for more details about ordering.
- On half of the paper plates (one per student), draw two intersecting lines to form four equal quarters.
- On the backs of the second set of paper plates (one per student), draw the same intersecting lines. Trace around a quarter in the center and keep the circle in tact. Cut out a ¼-quadrant from these paper plates to act as windows.
- Make multiple copies of the Student Recording Sheets (PDF) printable. You should have one sheet per student for each day you plan to observe the insects (at least four per student so the students can record each stage of the insect life cycle).
- If the insects did not arrive in separate cups or containers, place the insect larva in separate cups or containers for each student.
When ordering the live insect larva or eggs, be sure to allow enough time for delivery. Avoid beginning the process near school breaks, so the metamorphasis doesn't occur when students are gone! I have used mealworms, silkworm eggs, and monarch butterfly caterpillars in the past. Mealworms can be purchased at pet stores. I have silkworm eggs that moths laid last year that I kept in the refrigerator. Tiny caterpillar larva with individual plastic cups for each student can be purchased from educational supply catalog companies.
Step 1: Begin the lesson by reading The Very Hungry Caterpillar. Tell students that some insects change completely during their life cycle. This is called metamorphosis. Just like the tiny caterpillar in Eric Carle’s story, some insects go through four stages: egg, larva, pupa, adult. In the story, the first stage is an egg. Show the photograph of an egg or show the picture from the book. Continue by describing the second stage: the larva or caterpillar. The third stage is the pupa, which is inside the chrysalis. The fourth step is the adult butterfly.
Step 2: Distribute the paper plates with the four equal quadrants. Guide students in drawing the four stages in the butterfly life cycle:
- Upper right quadrant: Egg
- Bottom right quadrant: Larva or caterpillar
- Bottom left quadrant: Pupa inside the chrysalis
- Upper left quadrant: Adult butterfly
Note: Remind students that the butterfly is an insect and must have the correct amount of legs and body parts. Encourage them to label their pictures by the stage.
Step 3: Distribute the second paper plate and a brass brad to each student. Ask students to put the cut plate over the first and push the brass brad through the hole.
Step 4: Bring students together and demonstrate how to show each of the four stages by moving the plate with the window cut out.
Step 1: Remind students about the four stages of the butterfly life cycle. Even if the insects you will have in class are not butterflies, the four stages should still be the same.
Step 2: Distribute the Student Recording Sheets printable. Explain that students will be observing their own insect eggs or larvae. As scientists, they will record their observations of the developing insect. They should list the day, draw a picture of their insect, and write about it on the Student Recording Sheet. At the end, these will be collected and made into an observation journal.
Step 3: Distribute the insect eggs or larvae and magnifying glasses to the students.
Step 4: Instruct students to write Day 1 at the top of their Recording Sheet. Ask them each to draw a picture of the insect and write their observations.
Note: You may want to include craft sticks if you are using meal worms so that students can move them around.
Step 5: Gather students together to share their observations.
Day 3 and Beyond
Step 1: Every few days, distribute a new recording sheet and have students draw and record notes about their insects.
Step 2: Gather students together to share their observations as a class. Encourage students to ask questions during this time.
Supporting All Learners
Where appropriate, help students to label the stages. Take dictation for those students who aren't yet writing on the Recording Sheets.
- Dramatize the four stages of the insect metamorphosis with dramatic play or a Readers Theater script.
- Discuss other life cycles in nature.
Encourage students to discuss their own life cycle thus far (growing from infant to crawler to toddler to child) with their parents or guardians. They should discuss the different foods they ate at each stage and their changing needs.
- Make a life cycle plate.
- Keep an observation journal.
Observe how students record the changes in their insect. Note emergent writing and spelling patterns.
- Did students notice all stages of the life cycle in their observation journal?
- What would you do differently?