Lesson Note on Micro Organisms Around Us for SS1 (SSS 1)

Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 3rd Term
Week: 7
Age: 15 years
Duration: 45 minutes
Subject: Biology
Curriculum Theme: Biology
Previous Lesson: Population Growth & Food Supply.
Topic: MICRO-ORGANISMS AROUND US
Subject Matter: Classification of micro-organisms (viruses, bacteria, fungi, protozoa), carriers, vectors and transmitting organisms, beneficial and harmful effects, growth of micro-organisms, control and prevention of microbial diseases in public health.

Specific Objectives

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

Cognitive Domain:

• Define micro-organisms.
• Classify micro-organisms into viruses, bacteria, fungi, and protozoa.
• List beneficial and harmful effects of micro-organisms.
• State ways to control and prevent microbial diseases in public health.

Affective Domain:

• Appreciate the importance of hygiene in preventing microbial diseases.
• Value the role of micro-organisms in various aspects of life.

Psychomotor Domain:

• Collect samples from air, water, and fingernails for culturing.
• Set up simple cultures of micro-organisms in Petri dishes.

Social Domain:

• Work cooperatively in groups during practical activities.

Reference Materials

The following resources were used in planning this lesson:

• 9 Years Basic Education Curriculum for Biology (Senior Secondary Education)
• State Unified Scheme of Work for Biology SSS 1
• Essential Biology for Senior Secondary Schools by M.C. Michael

Instructional Materials

The teacher will teach this lesson with the aid of:

• Sterilized Petri dishes
• Culture medium (e.g., nutrient agar)
• Cotton swabs
• Water samples
• Gloves
• Hand sanitizer
• Labels
• Charts showing different types of micro-organisms

Rationale for the Lesson

This lesson helps pupils understand the invisible world of micro-organisms that exist all around them. It enables them to recognize both the positive and negative impacts these organisms have on human health and the environment, promoting awareness about hygiene and disease prevention.

Prerequisite/Previous Knowledge

Pupils have basic knowledge of living organisms and simple concepts of health and disease from their junior secondary school science.

Lesson Content/Board Summary

MICRO-ORGANISMS AROUND US

1. Definition of Micro-organisms

Micro-organisms are tiny living organisms that are too small to be seen with the naked eye. They can only be observed using a microscope.

2. Classification of Micro-organisms

Micro-organisms are broadly classified into the following groups:

• Viruses: Non-cellular, parasitic organisms that can only reproduce inside living cells (e.g., HIV, influenza virus).
• Bacteria: Single-celled prokaryotic organisms found everywhere (e.g., Salmonella, Lactobacillus).
• Fungi: Eukaryotic organisms that include yeasts, moulds, and mushrooms. Some are microscopic (e.g., Candida, Penicillium).
• Protozoa: Single-celled eukaryotic organisms, often found in water and soil (e.g., Amoeba, Plasmodium).

3. Carriers, Vectors, and Transmitting Organisms

A carrier is an individual who harbors a disease-causing micro-organism without showing symptoms but can transmit it to others. A vector is an organism (often an arthropod) that transmits a pathogen from one host to another.

Examples of vectors include:

• Mosquitoes (transmit malaria, dengue fever)
• Flies (transmit typhoid, cholera)
• Ticks (transmit Lyme disease)
• Rats (transmit Lassa fever)

4. Beneficial Effects of Micro-organisms

Micro-organisms are useful in the following ways:

• Food Production: Used in making bread, yoghurt, cheese, and alcoholic beverages.
• Decomposition: Break down dead organic matter, recycling nutrients in the ecosystem.
• Medicine: Used to produce antibiotics and vaccines.
• Digestion: Gut bacteria aid in the digestion of food and vitamin production in humans and animals.
• Bioremediation: Used to clean up oil spills and other pollutants.

5. Harmful Effects of Micro-organisms

Micro-organisms can cause harm by:

• Causing Diseases: Pathogenic micro-organisms cause infectious diseases in humans, animals, and plants (e.g., cholera, tuberculosis, measles).
• Food Spoilage: Cause food to rot and become unsafe for consumption.
• Material Damage: Some fungi and bacteria can cause decay in wood, fabrics, and other materials.

6. Growth of Micro-organisms

Micro-organisms grow and multiply rapidly under favourable conditions. Their growth can be observed on a culture medium in a Petri dish.

Factors affecting growth include:

• Temperature: Most micro-organisms have an optimal temperature range for growth.
• Nutrients: Require a source of food for energy and building blocks.
• Moisture: Water is essential for metabolic activities.
• pH: Grow best within specific pH ranges (acidity/alkalinity).
• Oxygen: Some require oxygen (aerobic), others do not (anaerobic).

7. Control and Prevention of Microbial Diseases in Public Health

Measures to control and prevent microbial diseases include:

• Hygiene: Regular handwashing, bathing, and maintaining clean surroundings.
• Sanitation: Proper disposal of waste, clean water supply, and effective sewage systems.
• Vaccination: Administering vaccines to provide immunity against specific diseases.
• Sterilisation and Disinfection: Using heat, chemicals, or radiation to kill micro-organisms on surfaces or medical instruments.
• Food Safety: Proper cooking, storage, and handling of food to prevent contamination.
• Vector Control: Eliminating vectors like mosquitoes and flies to break disease transmission cycles.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes

Teaching Skill: Set Induction

Teacher’s Activity: The teacher greets the pupils and asks them if they can see everything around them. The teacher then asks what they think are too small to be seen with the naked eye but are all around us. This leads to the topic of micro-organisms.

Pupils’ Activity: Pupils respond to questions and listen attentively.

Learning Point: Pupils are introduced to the concept of micro-organisms.

Step 2: Definition and Classification of Micro-organisms

Time: 10 minutes

Teaching Skill: Explanation/Classification

Teacher’s Activity: The teacher defines micro-organisms and explains their classification into viruses, bacteria, fungi, and protozoa, using charts to show examples of each. The teacher clarifies that viruses are non-cellular.

Pupils’ Activity: Pupils listen, take notes, and ask questions for clarification.

Learning Point: Pupils learn the definition and major classes of micro-organisms.

Step 3: Carriers, Vectors, and Transmitting Organisms

Time: 5 minutes

Teaching Skill: Explanation/Illustration

Teacher’s Activity: The teacher explains the terms ‘carrier’ and ‘vector’, providing examples of common vectors in Nigeria and the diseases they transmit.

Pupils’ Activity: Pupils listen and identify familiar examples of vectors.

Learning Point: Pupils understand how diseases are transmitted by carriers and vectors.

Step 4: Beneficial and Harmful Effects of Micro-organisms

Time: 8 minutes

Teaching Skill: Discussion/Brainstorming

Teacher’s Activity: The teacher leads a discussion on the beneficial roles of micro-organisms (e.g., in food, medicine, environment) and their harmful effects (e.g., causing diseases, food spoilage).

Pupils’ Activity: Pupils contribute ideas, giving examples of both beneficial and harmful micro-organisms.

Learning Point: Pupils identify the dual nature of micro-organisms as both useful and harmful.

Step 5: Growth of Micro-organisms (Practical Activity Setup)

Time: 10 minutes

Teaching Skill: Demonstration/Practical Guidance

Teacher’s Activity: The teacher divides pupils into groups and demonstrates how to collect samples from air, water, and under fingernails using cotton swabs. The teacher then guides pupils to carefully inoculate sterilized Petri dishes containing culture medium with their samples and label them. The teacher explains that observations will be made over the next few days.

Pupils’ Activity: Pupils work in groups, collect samples, and inoculate Petri dishes under supervision, following safety guidelines (wearing gloves, using hand sanitizer).

Learning Point: Pupils gain practical experience in culturing micro-organisms and understand the conditions for their growth.

Step 6: Control and Prevention of Microbial Diseases in Public Health

Time: 5 minutes

Teaching Skill: Explanation/Advocacy

Teacher’s Activity: The teacher explains various public health measures for controlling and preventing microbial diseases, emphasizing hygiene, sanitation, vaccination, and food safety.

Pupils’ Activity: Pupils listen and discuss the importance of these measures in their daily lives.

Learning Point: Pupils learn practical ways to prevent the spread of microbial diseases.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. Define micro-organisms.
2. Mention any three classes of micro-organisms.
3. List two beneficial effects of micro-organisms.
4. State three ways to control and prevent microbial diseases.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes

Teaching Skill: Summarisation

Teacher’s Activity: The teacher summarises the key points of the lesson, reiterating that micro-organisms are everywhere, have both good and bad effects, and proper hygiene is important for health. The teacher instructs pupils to observe their cultures over the next few days.

Pupils’ Activity: Pupils listen and prepare for the next lesson.

Learning Point: The lesson is brought to a logical close with a recap of main points.

Lesson Keywords

• Micro-organisms – Tiny living organisms not visible to the naked eye.
• Viruses – Non-cellular, parasitic micro-organisms.
• Bacteria – Single-celled prokaryotic micro-organisms.
• Fungi – Eukaryotic micro-organisms including yeasts and moulds.
• Protozoa – Single-celled eukaryotic micro-organisms.
• Vector – An organism that transmits a pathogen from one host to another.
• Pathogen – A micro-organism that causes disease.
• Culture medium – A substance used to grow micro-organisms in a laboratory.
• Hygiene – Practices that promote health and prevent disease, especially through cleanliness.

Differentiation

For pupils who grasp concepts quickly, the teacher can encourage them to research specific microbial diseases or beneficial applications of micro-organisms. For pupils needing more support, the teacher will provide simplified notes and pair them with more capable peers during the practical activity to ensure participation and understanding.

Note for teachers using this lesson plan

Ensure all safety precautions are strictly followed during the practical activity, especially when handling samples and Petri dishes. Emphasize the importance of sterile techniques. The observation of cultured micro-organisms can be extended into the next lesson or assigned as a project for pupils to record their findings over several days.