Morphological and Physiological Variation in a Population for SS 3

Class: SS 3
Term: First Term
Week: 7
Age: 16 years
Duration: 45 minutes
Subject: Biology
Topic: VARIATION IN POPULATION
Subject Matter: Morphological variation; (physical appearance of individuals); size, height, weight, colour (skin hair, eyes, coat of animals); finger print; Physiological variation; Behaviour; Ability to role tongue; Ability to taste phenyl thiocarbamide (PTC); Application of variations; (a) Crime detection; Blood transfusion; Determination of paternity
Previous Lesson: Mendel’s Work and Applications of Heredity

Specific Objectives

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

Cognitive Domain

• Define morphological variation.
• List examples of morphological variation in humans and animals.
• Define physiological variation.
• List examples of physiological variation in humans.
• Explain the applications of variation in real-life scenarios.

Affective Domain

• Appreciate the diversity among individuals in a population.
• Value the importance of understanding variation in fields like medicine and forensics.

Psychomotor Domain

• Measure and compare the heights of individuals.
• Demonstrate the ability to roll their tongue.
• Identify different fingerprint patterns.

Reference Materials

The following resources were used in planning this lesson:

• 2025 Revised 9 Years Basic Education Curriculum
• Relevant State Unified Scheme of Work
• Essential Biology for Senior Secondary Schools
• The HeadTeacher Scheme of work

Instructional Materials

The teacher will teach this lesson with the aid of:

• Measuring tape or height chart
• Charts showing different skin, hair, and eye colours
• Diagrams or samples of different fingerprint patterns (e.g., whorl, arch, loop)
• PTC (phenylthiocarbamide) paper (if available)
• Pictures illustrating crime detection, blood transfusion, and paternity determination

Rationale for the Lesson

This lesson helps students understand why individuals within a species are not identical, even though they share common characteristics. It provides a foundation for understanding evolution and genetics by exploring observable and functional differences. Knowledge of variation is also practical, with applications in forensic science, medicine, and legal processes.

Prerequisite/Previous Knowledge

Students should have a basic understanding of living organisms, their characteristics, and the concept of a population from their previous biology classes.

Lesson Content/Board Summary

VARIATION IN POPULATION

Morphological Variation

Morphological variation refers to the differences in the physical appearance or observable structural traits among individuals within a population. These are traits that can be seen or measured.

Examples of morphological variation include:

1. Size: Differences in the overall dimensions of an individual.
2. Height: Variation in vertical stature.
3. Weight: Differences in body mass.
4. Colour:
   1. Skin colour: Ranging from light to dark.
   2. Hair colour: Such as black, brown, blonde, red.
   3. Eye colour: Such as brown, blue, green, grey.
   4. Coat colour of animals: Differences in fur or feather colour.
5. Fingerprint patterns: Unique ridge patterns on fingertips, such as:
   1. Whorl: Circular or spiral patterns.
   2. Arch: Ridges that rise in the centre and fall to either side.
   3. Loop: Ridges that enter from one side, loop around, and exit from the same side.

Physiological Variation

Physiological variation refers to the differences in the functional processes or internal workings of the body among individuals. These variations are often related to how the body performs certain actions or responds to stimuli.

Examples of physiological variation include:

1. Behaviour: Differences in responses to environmental stimuli, habits, or temperament.
2. Ability to roll tongue: Some individuals can roll their tongue into a U-shape, while others cannot. This is a genetically determined trait.
3. Ability to taste phenylthiocarbamide (PTC): Some people can taste PTC as bitter, while others find it tasteless. This is also a genetically determined trait.
4. Blood groups: Differences in the types of antigens on red blood cells (e.g., A, B, AB, O).

Applications of Variations

Understanding variations among individuals has several practical applications:

1. Crime detection (Forensics):
   1. Fingerprints: Unique to each individual and used for identification at crime scenes.
   2. Blood groups and DNA: Used to match suspects to biological samples found at crime scenes.
2. Blood transfusion:
   1. Knowing blood groups is critical to ensure compatibility between donor and recipient to prevent adverse reactions.
3. Determination of paternity:
   1. Comparing blood groups and DNA profiles of a child, mother, and alleged father can establish biological relationships.

Teaching Methods/Instructional Techniques

Discussion, Demonstration, Guided Practice, Question and Answer, Explanation, Observation, Group Work, Individual Practice.

Instructional Procedures

Step 1: Introduction

Time: 5 minutes

Teaching Skill: Engaging, Questioning

Teacher’s Activity: The teacher greets the students and asks them to observe their classmates, noting any obvious differences in appearance. The teacher then introduces the topic of variation in a population.

Pupils’ Activity: Students observe their classmates and share some differences they notice (e.g., height, skin colour). They listen attentively to the introduction.

Learning Point: Introduction to variation

Step 2: Explanation of Morphological Variation

Time: 8 minutes

Teaching Skill: Explanation, Listing

Teacher’s Activity: The teacher defines morphological variation and provides examples such as size, height, weight, and colour (skin, hair, eyes, coat of animals). The teacher uses charts to illustrate different colour variations.

Pupils’ Activity: Students listen, ask questions, and contribute additional examples of morphological variation.

Learning Point: Morphological variation defined

Step 3: Practical Activity on Morphological Variation

Time: 8 minutes

Teaching Skill: Demonstration, Guided Practice

Teacher’s Activity: The teacher measures the height of a few students from different age groups (e.g., 13-15 and 16-17 years) to demonstrate height variation. The teacher also demonstrates how to make fingerprints and identifies the different patterns (whorl, arch, loop) using a chart or prepared samples.

Pupils’ Activity: Students observe the height measurements, compare their own heights, and participate in making and identifying fingerprint patterns.

Learning Point: Examples of morphological variation

Step 4: Explanation of Physiological Variation

Time: 7 minutes

Teaching Skill: Explanation, Illustrating

Teacher’s Activity: The teacher defines physiological variation, explaining that these are functional differences. Examples like behaviour, ability to roll the tongue, and ability to taste PTC are discussed.

Pupils’ Activity: Students listen and understand the concept of physiological variation, asking clarifying questions.

Learning Point: Physiological variation defined

Step 5: Practical Activity on Physiological Variation

Time: 5 minutes

Teaching Skill: Observation, Guided Practice

Teacher’s Activity: The teacher asks students to attempt to roll their tongues and observe who can and cannot. If PTC paper is available, the teacher can conduct a simple tasting test. The teacher also asks students if they know their blood group as another example of physiological variation.

Pupils’ Activity: Students attempt tongue rolling, participate in the PTC test (if applicable), and share if they know their blood group.

Learning Point: Physiological variation examples

Step 6: Discussion on Applications of Variation

Time: 4 minutes

Teaching Skill: Discussion, Application

Teacher’s Activity: The teacher leads a discussion on how variations are applied in real life, specifically focusing on crime detection (fingerprints, blood groups), blood transfusion, and determination of paternity.

Pupils’ Activity: Students participate in the discussion, sharing their thoughts and understanding of the applications.

Learning Point: Applications of variation

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. What is morphological variation? Give two examples.
2. What is physiological variation? Give an example.
3. Mention two applications of variation in real life.
4. Name three types of fingerprint patterns.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Understanding of variations

Step 8: Note-Taking

Time: 4 minutes

Teaching Skill: Guided Writing

Teacher’s Activity: The teacher guides pupils/students to copy the essential Board Summary notes into their notebooks, ensuring they capture the definitions and examples of morphological and physiological variations and their applications.

Pupils’ Activity: Pupils/students copy the notes carefully into their notebooks.

Learning Point: Key concepts recorded

Step 9: Conclusion

Time: 2 minutes

Teaching Skill: Summarizing, Reinforcement

Teacher’s Activity: The teacher briefly reinforces the main idea that variation is a natural and important aspect of all populations, with significant implications in various fields. The teacher encourages students to continue observing variations around them.

Pupils’ Activity: Students listen and reflect on the lesson’s main points.

Learning Point: Variation importance reinforced

Continuous Assessment/Further Study

Type: Homework

Instruction: Answer the following questions in your notebook:

1. Differentiate between morphological and physiological variation, providing two examples for each.
2. Research and write a short paragraph on how DNA profiling is used in crime detection.
3. Identify two other examples of variation you observe in your family or community, apart from those discussed in class.

Lesson Keywords

• Variation – Differences among individuals in a population.
• Morphological – Relating to the physical form or structure.
• Physiological – Relating to the normal functioning of a living organism.
• Fingerprint – Unique ridge patterns on fingertips.
• PTC – Phenylthiocarbamide, a chemical used to test for a specific taste ability.
• Paternity – The state of being a father.

Differentiation

For weaker learners, the teacher can provide simplified definitions and focus on identifying common examples of variation. Visual aids like charts and diagrams should be used extensively. For faster learners, the teacher can encourage research into other types of variation (e.g., genetic variation) or more complex applications of variation in fields like genetic engineering or disease resistance.

Suggested Lesson Videos

For further understanding, students can search for “Biological Variation in Human Populations” or “Morphological and Physiological Variation” on YouTube.

Teacher Guide for Using This Lesson Plan

Before the lesson, ensure you have a measuring tape, charts displaying different human features (skin/eye/hair colour), and examples or diagrams of fingerprint patterns. If possible, procure PTC paper for a hands-on physiological variation activity. Begin by engaging students with observations of their peers to introduce the concept of variation. Guide them through the definitions and examples of morphological and physiological variations, making sure to include the practical activities as outlined. Emphasize the real-world applications of understanding variation. During the note-taking stage, ensure students copy the Board Summary accurately. Pay attention to students who may struggle with distinguishing between morphological and physiological traits, providing additional examples and analogies. Encourage critical thinking for faster learners by asking them to consider the evolutionary significance of variation.