Biology Guides SS 2 The Organism at Work – Digestive System, Excretory System, Respiratory System and Transport System

BIOLOGY 

THEME – THE ORGANISM AT WORK 

TOPIC 1 – DIGESTIVE SYSTEM

INSTRUCTIONAL MATERIALS

1. Dissected specimens showing the alimentary canals of earthworm, bird and rabbit

2. Specimens and/or charts of digestive system of housefly, butterfly, cockroach, sheep and dog

3. Diagrams of mouth parts of some insects

4. Teeth models of some animals, e.g. dog, man, etc.

LEARNING OBJECTIVES

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

1. describe with appropriate illustrations different types of alimentary tracts.

2. explain the feeding mechanism of some animals.

3. explain how some insectivorous plants feed.

CONTENTS OF THE LESSON

FOCUS LESSONS 

1. Types of alimentary tracts

2. Describe the functions of the parts of the alimentary canal.

3. Modifications of parts to effect their digestive functions.

4. Feeding habits:

categories and mechanisms.

5. Modifications in the feeding habits of:

• filter feeders

• fluid feeders

• insects feeders

• parasitic and saprophytic feeders

6. Feeding in protozoa, hydra and mammals

LESSON PRESENTATION

TEACHER’S ACTIVITIES

The teacher,

1. With the aid of dissect specimens, models or charts, teaches the alimentary canals of planarian, earthworm, grasshopper, birds and rabbits.

2. Uses the specimens and charts of the digestive system of housefly, butterfly, cockroach, tapeworm, sheep and dog to illustrate different types of feeding mechanisms.

3. Explains with well drawn charts the differences in the mouth parts of some insects.

4. Shows students specimens of different teeth to illustrate modifications in feeding habits of animals.

 

STUDENT’S ACTIVITIES

The students,

1. Observe the learning materials and compare the various alimentary canals.

2. Observe the specimens noting the various modifications found in the animals.

3. Identify the modified mouth parts.

LESSON EVALUATION

Students to,

1. explain the feeding mechanism of the listed animals, housefly, cockroach and dog.

2. give reasons for the modifications found in listed animals (dog, man, etc).

3. describe briefly the modifications and mechanisms associated with a named filter feeder and parasitic feeder.

BIOLOGY 

THEME – THE ORGANISM AT WORK 

TOPIC 2 – EXCRETORY SYSTEM

INSTRUCTIONAL MATERIALS

1. Dissected cockroach showing malpighian tubules, dissected rat and kidney of the sheep.

2. Dicotyledonous leaf, glass slides and microscope.

3. Charts or diagrams of nephron.

LEARNING OBJECTIVES

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

1. identify and describe different types of excretory systems in plants and animals.

2. explain the mechanisms of some of the excretory organs and relate structure to functions.

CONTENTS OF THE LESSON

FOCUS LESSONS 

1. Excretory systems:

• Contractile vacuoles

• Flame cells

• Malpighian tubules

• Kidney

• Stomata and lenticel

2. Excretory mechanism in:

• Earthworm

• Insects

• Mammals

LESSON PRESENTATION

TEACHER’S ACTIVITIES

The teacher,

1. Discusses the various excretory systems with the students.

2. Asks students to observe:

• malpighian tubules in a dissected cockroach.

• excretory system in a dissected rat.

• internal structure of a dissected kidney of a sheep of pig.

3. Removes the epidermis of the lower surface of a dicotyledonous leaf.

4. Prepares a wet mount slide and asks students to examine the kidney shaped guard cells and the stomata in the centre of the cells.

5. Displays charts or diagrams of nephron to students, leads them to identify the different parts and relate the identified parts to the functions they perform.

 

STUDENT’S ACTIVITIES

The students,

1. Take part in discussion.

2. Observe and draw the malpighian tubules, the excretory system of rat and the internal structure of the kidney of a sheep or pig.

3. Observe the slide, record the observations and make a labelled diagram of the guard cells and the stomata.

4. Relate parts identified to functions.

LESSON EVALUATION

Students to,

1. identify and describe the different excretory systems presented.

2. draw and label a mammalian kidney.

BIOLOGY 

THEME – THE ORGANISM AT WORK 

TOPIC 3 – RESPIRATORY SYSTEM

INSTRUCTIONAL MATERIALS

1. Prepared slide

2. Gills of tilapia

3. Chalkboard, relevant diagrams/charts

4. Cellophane tubing to make models of stomata

5. Microscope

LEARNING OBJECTIVES

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

1. describe the different types of respiratory systems.

2. list the characteristics of a respiratory surface.

3. draw and label some of the respiratory organs of some animals.

4. explain the various mechanisms of respiration in some animals, e.g mammals.

5. describe the mechanism of exchange of gasses through the stomata of plants.

CONTENTS OF THE LESSON

FOCUS LESSONS 

1. Types of respiratory systems: 

• Body surface respiration 

• Cutaneous respiration

• Gills  

• Tracheal system

• Lungs 

2. Mechanisms of respiratory system in:

• higher animals

• lower animals

• plants

3. Mechanisms of gaseous exchange through the stomata of plants.

LESSON PRESENTATION

TEACHER’S ACTIVITIES

The teacher,

1. Mounts prepared slides showing respiratory organs of earthworm, tilapia, toad, grasshopper and rat.

2. Displays the gills removed from a dead tilapia for students to observe the various structures.

3. Discusses respiratory movements in higher and lower animals and in plants.

4. Leads students to perform experiments showing effects of turgidity on the opening and closing of stomata using a model of stomata.

 

STUDENT’S ACTIVITIES

The students,

1. Observe the respiratory organs of the various animals.

2. Observe the gill fakes, gill arch and the gill filaments and draw.

3. Make notes on the respiratory mechanisms.

4. Observe and record their observations.

LESSON EVALUATION

Students to,

1. draw and labe the respiratory organs.

2. state the number of gills in each chamber and how they are attached.

3. explain the mechanisms of respiration in a named lower and higher animals and plants.

4. describe gaseous exchange through the stomata of leaves.

BIOLOGY 

THEME – THE ORGANISM AT WORK 

TOPIC 4 – TRANSPORT SYSTEM

INSTRUCTIONAL MATERIALS

1. Diagrams showing arteries, veins, capillaries and vascular bundles.

2. Prepared slide of tradescantia petal.

3. Prepared slide of artery and vein.

4. Charts of cockroach or grasshopper, toad or frog and a named small mammal.

5. Cosine , a young herbaceous plant, beaker, blade, glass slide and light microscope.

LEARNING OBJECTIVES

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

1. define diffusion.

2. explain the inadequacy of diffusion alone as a transport system for complex organisms.

3. explain the necessity of a transport system in complex organisms.

4. identify source of materials and where they are transported to.

5. discuss the different types of transportation media such as cytoplasm, cell sap, lymph and blood.

6. describe the mechanisms of transportation in various animals.

7. compare and contrast various mechanisms of transportation.

8. demonstrate experimentally the flow of materials in plant.

CONTENTS OF THE LESSON

FOCUS LESSONS 

1. Definition of diffusion and osmosis and the principles behind them.

2. Need for diffusion.

3. Transport system in large organisms.

4. Need for substances to move over greater distances.

5. Materials for transportation.

6. Structure of arteries, veins, capillaries, vascular bundles.

7. Media of transportation

• Fluid as medium of transportation-structure and function of blood.

• cytoplasm in small organisms

• cell sap or latex in most plants

• closed and open circulation.

8. Mechanisms of transportation:

• organisms

• multicellular organisms

• higher animals

• higher plants

9. Absorption of water and minerals salts.

LESSON PRESENTATION

TEACHER’S ACTIVITIES

The teacher,

1. Set up an experiment on rate of diffusion of a coloured liquid.

2. Instructs students to detach the leaves of pawpaw, cassava, allamanda, thevetia (milk bush) or rubbet required.

3. Explains the structure of artery/vein etc. using well drawn diagrams.

4. Mounts the slide of the young petal of Tradescantia plant.

5. Mounts a slide of blood smear and transverse section of an artery and a vein.

6. Dissects:

• cockroach or grasshopper to expose the heart.

• toad, frog or a small mammal to show the heart and some blood vessels.

7. Guide students to set up an experiment showing absorption of water in higher plant.

 

STUDENT’S ACTIVITIES

The students,

1. Observe the experiments and carefully record the time taken by the coloured liquid to diffuse.

2. Detach the leaves of those plants.

3. Observe and make inferences on the materials the plants transport.

4. Note the structures.

5. Examine the slides, observe and draw noting the cytoplasm and granules around the hair cell.

6. Observe and draw the slides of blood smear, and transverse section of an artery and a vein

7. Examine and draw dissected specimens.

8. Locate the transport vessels. Note the differences in the thickness of the walls of the vessels.

9. Observe the experiment and make inferences.

LESSON EVALUATION

Students to,

1. write short notes on the structures of arteries and vascular bundles.

2. make large labeled diagrams of the specimens.

3. what are the differences between the transport system in small animals and large animals.

4. name two transportation media in large animals.