Level: JHS, Basic 8 | Subject: Integrated Science | Strand: Cycles | Topic: Life Cycle of Organisms (The Mosquito)
Curriculum reference: B8.2.2.1 Understand the life cycle of a mosquito and its health implications. Indicators B8.2.2.1.1 (life cycle of a mosquito) and B8.2.2.1.2 (mosquitoes as vectors of diseases and methods of control) are merged into one set of notes.
1. The Life Cycle of the Mosquito
The mosquito goes through complete metamorphosis, which means four stages that look very different from each other.
| Stage | Where | What it looks like |
|---|---|---|
| 1. Egg | On the surface of still water, such as puddles, gutters, old tyres and open containers | Tiny; laid singly or in a group called a raft |
| 2. Larva (wriggler) | In water, hanging at the surface | Worm-like; breathes through a tube at the tail end; feeds on tiny living things |
| 3. Pupa (tumbler) | In water, near the surface | Comma-shaped; does not feed; changes into the adult |
| 4. Adult | Leaves the water and flies | Slim body, six legs, one pair of wings, long mouthparts for piercing |
The cycle is: egg, larva, pupa, adult. Pupils can see the stages by keeping some stagnant water in a jar for a few days or by watching a video, and then drawing and labelling each stage.
2. Mosquitoes as Vectors of Disease
- A vector is an organism that carries disease-causing germs from one person to another.
- Only the female mosquito bites people because she needs blood to produce eggs. Male mosquitoes feed on plant juices.
- The female Anopheles mosquito carries the malaria parasite (Plasmodium). When she bites an infected person, she picks up the parasite. When she bites another person, she passes it on.
- Other mosquitoes spread yellow fever, dengue fever and filariasis.
- Signs of malaria: fever, headache, shivering, sweating, vomiting and body pains. Malaria is a leading cause of illness in Ghana and can kill young children if not treated early.
3. Methods of Controlling Mosquitoes
| Type | Examples |
|---|---|
| Environmental | Clear gutters and bushes; fill or drain stagnant water; cover water containers; throw away old tins and tyres; keep the surroundings clean |
| Chemical | Spray insecticide; pour used oil or larvicide on breeding water; use mosquito coils |
| Biological | Introduce fish such as tilapia that feed on larvae |
| Personal protection | Sleep under insecticide-treated mosquito nets; fix nets on windows and doors; wear long sleeves in the evening; use repellents |
Remember: Egg, larva, pupa, adult. The female Anopheles mosquito spreads malaria. Destroy breeding places and sleep under a treated net.
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Education Always (education.inspiringalways.com). Original notes written to follow the NaCCA Basic 8 Integrated Science curriculum.