Changes in Plants and Animals (III)

TOPIC: Changes in Plants and Animals
SUBTOPIC: Life Cycle of Insects
CLASS: PRIMARY 4
DATE: ____________________
PERIOD: ____________________
DURATION: 40 minutes

LEARNING OBJECTIVES:
By the end of the lesson, pupils should be able to:

1. Identify some common insects.
2. Describe the life cycle of insects.
3. Draw and label insect life cycles.
4. Compare stages of insect development.

KEY VOCABULARY WORDS: egg, larva, pupa, adult, metamorphosis.

INSTRUCTIONAL MATERIALS:

• Chart showing life cycles of butterfly, mosquito, housefly
• Model insects or plastic toys
• Pictures showing each stage

CONTENT OF THE LESSON:

Meaning of Life Cycle:
The life cycle of an insect is the series of changes it passes through from the egg stage until it becomes an adult.

Types of Insect Life Cycles:

1. Complete Metamorphosis – Insects change completely in appearance from young to adult. Stages:
   • Egg → Larva → Pupa → Adult
   • Examples: Butterfly, mosquito, housefly.
2. Incomplete Metamorphosis – Young insects look like small adults but without wings. Stages:
   • Egg → Nymph → Adult
   • Examples: Grasshopper, cockroach.

Example: Life Cycle of a Butterfly

• Egg: Laid on leaves.
• Larva (Caterpillar): Eats leaves, grows bigger.
• Pupa (Chrysalis): Resting stage, body changes inside.
• Adult Butterfly: Fully grown with wings, ready to reproduce.

Table: Complete vs Incomplete Metamorphosis

INTRODUCTORY ACTIVITY:
Teacher displays pictures of insects at different stages and asks pupils to arrange them in order.

CLASS EXERCISE 1:
List the four stages of complete metamorphosis.

CLASS EXERCISE 2:
Name two insects that undergo incomplete metamorphosis.

ASSIGNMENT (MCQs):

1. The resting stage in complete metamorphosis is called (a) larva (b) pupa (c) adult
2. A grasshopper undergoes (a) complete metamorphosis (b) incomplete metamorphosis (c) no change
3. The first stage of any insect life cycle is (a) egg (b) larva (c) pupa
4. In incomplete metamorphosis, the young insect is called (a) nymph (b) caterpillar (c) chick
5. The larva of a butterfly is also called (a) grub (b) caterpillar (c) maggot