Lesson Notes By Weeks and Term - Senior Secondary 3

Variation in population

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TERM – 1ST TERM

WEEK SEVEN

Class: Senior Secondary School 3

Age: 17 years

Duration: 40 minutes of 5 periods each

Date:

Subject: Biology

Topic: Variation In Population

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

  1. Describe morphological Variation
  2. Describe physiological variation
  3. Identify the applications of variation.

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 measures the height of students of the same age group e.g. 13-15 and 16-17 year

Students participate

STEP 2

EXPLANATION

Teacher discusses the morphological and physiological variation in living organisms

Students pay

attention and

participate

STEP 3

DEMONSTRATIO

N

Teacher discusses the applications of variation

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

VARIATION IN POPULATION

Morphological Variation

Morphological variation refers to the observable differences in the physical characteristics or form of individuals within a population, species, or group. These variations can include traits such as size, shape, color, and other features that can be visually distinguished. Morphological differences can arise due to genetic factors, environmental influences, or a combination of both.

a) Size, Height, Weight: Morphological variation in size, height, and weight refers to the differences in physical dimensions among individuals. This can be influenced by genetic factors, environmental conditions, and nutritional factors. For example, different breeds of dogs may exhibit variations in size and weight due to selective breeding.

b) Color (Skin, Hair, Eyes, Coat of Animals): Variation in color is a common aspect of morphological diversity. In animals, skin, hair, eyes, and coat color can vary significantly within a species. This variation can serve various purposes, such as camouflage, communication, or adaptation to different environments. Humans also exhibit diverse skin, hair, and eye colors influenced by genetic factors.

c) Fingerprint: Fingerprint patterns are unique to each individual and exhibit morphological variations. The distinct ridges, loops, and whorls in fingerprints are not only unique but also relatively stable throughout a person's life. This characteristic has made fingerprints a crucial tool in forensic science and personal identification.

Physiological variation

Physiological variation refers to the natural differences in the physiological functions and characteristics among individuals within a population or species. This includes variations in processes such as metabolism, organ function, biochemical reactions, and other aspects of the body's physiology. Physiological variations can arise from genetic factors, environmental influences, or a combination of both. Examples of physiological variations include differences in blood pressure, heart rate, hormone levels, enzyme activity, and responses to stimuli.

a) Behavior: Physiological variation in behavior refers to differences in how individuals or species respond to stimuli, interact with their environment, or exhibit specific patterns of activity. Behavioral variations can be influenced by genetic factors, environmental conditions, and learning experiences.

b) Ability to Roll Tongue: The ability to roll the tongue is a physiological trait that shows individual variation. This characteristic is often used as an example in genetics, where some individuals can perform this action (due to a dominant gene), while others cannot. The ability to roll the tongue is inherited, but environmental factors can also play a role.

c) Ability to Taste Phenylthiocarbamide (PTC): The ability to taste PTC is a genetic trait related to taste perception. Some individuals can taste PTC, while others cannot, and this difference is determined by variations in specific taste receptors. This trait is often used in studies of human genetics and demonstrates how genetic factors can influence physiological responses.

Application of variation

  1. Crime Detection: Variations, particularly in genetic traits such as DNA fingerprints or unique physiological characteristics, play a crucial role in crime detection. DNA analysis helps identify individuals, establish relationships, and link individuals to crime scenes. The uniqueness of genetic markers contributes significantly to forensic investigations.
  2. Blood Transfusion: Understanding variations in blood types is essential for safe blood transfusions. ABO and Rh blood group systems, which exhibit individual variation, must be carefully matched between donors and recipients to prevent adverse reactions. Knowledge of these variations ensures compatibility and successful blood transfusions.
  3. Determination of Paternity: Genetic variations, especially in DNA sequences, are employed in determining paternity. By comparing specific genetic markers between a child and potential parents, scientists can establish biological relationships. This is valuable in legal contexts, such as child custody cases or inheritance disputes.

EVALUATION: 1. What is morphological Variation

  1. Identify 3 morphological Variation in organisms
  2. What is physiological variation
  3. Identify 3 physiological variation in organisms
  4. Discuss the applications of variation

CLASSWORK: As in evaluation

CONCLUSION: The teacher commends the students positively