Lesson Notes By Weeks and Term - Senior Secondary 1

TERM – 1^ST TERM

WEEK NINE

Class: Senior Secondary School 1

Age: 15 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Biology

Topic: EXCRETION

SPECIFIC OBJECTIVES: At the end of the lesson, pupils should be able to

1. Define excretion
2. Identify organisms with their respective excretory organs
3. Define reproduction
4. Identify the various types of Reproduction.
5. Differentiate between sexual and asexual reproduction.

INSTRUCTIONAL TECHNIQUES: Identification, explanation, questions and answers, demonstration, videos from source

INSTRUCTIONAL MATERIALS: Videos, loud speaker, textbook, pictures

INSTRUCTIONAL PROCEDURES

PERIOD 1-2

PRESENTATION	TEACHER’S ACTIVITY	STUDENT’S ACTIVITY
STEP 1 INTRODUCTION	The teacher discusses excretion and list organisms with their excretory organs	Students pay attention
STEP 2 EXPLANATION	Teacher explain reproduction and discuss the types of reproduction	Students pay attention and participate
STEP 3 DEMONSTRATIO N	Teacher aid students to spot differences between sexual and asexual reproduction	Students pay attention and participate
STEP 4 NOTE TAKING	The teacher writes a summarized note on the board	The students copy the note in their books

 

NOTE

EXCRETION

Excretion is the process by which living organisms eliminate waste products and excess substances from their bodies to maintain internal balance and prevent the accumulation of harmful substances. This biological process plays a crucial role in maintaining homeostasis.

Organisms and their Excretory Organs/Products

Organisms	Excretory organs	Excretory products
Humans	Kidneys	Urine (contains urea, excess salts, and water)
Fish	Gills (for removing ammonia) and kidneys	Ammonia, which is released into the water
Birds	Kidneys	Uric acid, which is excreted as a semi-solid paste along with minimal water loss
Insects	Malpighian tubules	Uric acid, excreted as dry pellets
Reptiles	Kidneys	Varied; some reptiles excrete uric acid, while others may excrete urea
Mammals (non-human)	Varies; for example, rodents have specialized structures like Harderian glands.	Varying types of waste products, including urea or other nitrogenous compounds.

 

REPRODUCTION

Reproduction is the biological process by which new individuals of the same species are produced, ensuring the continuity of life. It is a fundamental characteristic of living organisms and can occur through various mechanisms.

Types of Reproduction

1. Asexual Reproduction: The production of offspring without the involvement of gametes (sex cells) or the union of genetic material from two parents. Examples of asexual reproduction includes:

      - Binary Fission: Division of a single organism into two equal parts (e.g., bacteria).

       

      - Budding: New individuals develop as outgrowths from the parent organism (e.g., hydra).

      - Fragmentation: Breaking of the parent organism into fragments, each of which can grow into a new individual (e.g., starfish).

2. Sexual Reproduction: The formation of offspring by the fusion of gametes (sperm and egg) from two parent organisms, resulting in genetic diversity. The following are examples of sexual reproduction:

      - Internal Fertilization: Fusion of gametes occurs inside the body of the parent (e.g., mammals, birds).

      - External Fertilization: Fusion of gametes occurs outside the body, typically in aquatic environments (e.g., fish, amphibians).

      - Pollination and Seed Formation: In plants, sexual reproduction involves the transfer of pollen between flowers, leading to seed formation.

Differences between asexual and sexual reproduction

Aspects	Asexual reproduction	Sexual reproduction
Number of Parents	Typically one parent involved.	Requires the involvement of two parents - male and female.
Genetic Variation	Offspring are genetically identical to the parent	Offspring inherit a combination of genetic material from both parents, leading to genetic diversity.
Gametes	Gametes (sex cells) are not involved.	Formation and fusion of gametes (sperm and egg) are integral to the process.
Inheritance of Traits	Limited variation in traits, as they are inherited from a single parent.	Increased variation in traits due to the mixing of genetic material from two parents.
Speed of Reproduction     Examples in nature	Generally faster, as it doesn't involve complex processes like gamete formation and fertilization. Binary fission, budding and fragmentation	Slower, as it involves the production of specialized cells, mating, and fertilization.   Mammals, birds, fish and most higher organisms that reproduce sexually

 

EVALUATION: 1. Define excretion

2. Mention five organisms and identify their excretory organs
3. What is reproduction
4. Differentiate between sexual and asexual reproduction

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively