SHS3 Biology · Semester 1 Week 8: Cell Structure and Functions

Lesson notes

Learning Objectives

Indicator: 3.2.1.LI.1 - Explain Mendel’s laws of inheritance.

By the end of the lesson, learners can:

State Mendel’s three laws of inheritance: the Law of Segregation, the Law of Independent Assortment, and the Law of Dominance, using the correct genetic terminology.
Explain the key events in Mendel’s experiments with the pea plant that led to the formulation of each law.
Apply the Law of Segregation and the Law of Independent Assortment to predict the genotypic and phenotypic ratios of offspring in monohybrid and dihybrid crosses, using Punnett squares.
Use the Law of Dominance to explain why certain traits appear in the F1 generation while others disappear and reappear in the F2 generation.
Demonstrate the practical application of Mendel’s laws using simple models (such as marbles of different colours) to simulate the segregation and independent assortment of alleles.

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Curriculum details

Strand: Life in the Fundamental Unit (Strand 2)
Sub-strand: Cell Structure and Functions (2.1)
Content standard: 3.2.1.CS.2 - Demonstrate knowledge and understanding of Mendel's laws and concepts of inheritance, blood groups and their applications in life. 3.2.2.LO.1 Explain key terms in Genetics and their applications. 3.2.1.LO.2 Relate Mendel's laws and concepts of inheritance to human blood groups and their importance. 3.2.1.LO.3 Explain the concept of variation, its causes, processes, and consequences in life. 3.2.1.LO.4 Explain evolution and the factors leading to its occurrence in nature. 3.2.1.LO.5 Explain the cell cycle, cell division, and their relevance in living things.
Indicator: 3.2.1.LI.1 - Explain Mendel's laws of inheritance.
Suggested placement: Semester 1, Week 8 (Week 8 of the year)
Our suggestion, laid out in curriculum order across three terms of twelve weeks. NaCCA does not fix the week, so follow your school's scheme of learning.
Curriculum reference: NaCCA curriculum document, p. 97

Exemplars (from the NaCCA curriculum)

Experiential, Project-Based Learning: in mixed ability, all-inclusive groups, learners research from textbooks and libraries on Mendel's experiments with the pea plant, and the class embarks on a visit to a nearby farm (e.g. the school farm) where learners may observe common organisms used as models for genetic experiments. Equally, learners may observe charts and pictures showing the results of Mendel's experiments on monohybrid and dihybrid inheritance. Learners note their observations for presentation. Learners develop self and group emotional and social support in these activities.
Task-Based Learning Approach: using marbles of different colours demonstrate the application of Mendel's first law (law of segregation), second law (law of independent assortment), and third law (the law of Dominance) of inheritance in mixed ability, all-inclusive groups. Learners acquire self-confidence and emotional satisfaction by experiencing genetic principles and how they work through such simple exercises.
Talk-for-Learning Approach: using practical examples, discuss, based on the groups, how Mendel's laws can be applied to ensure the breeding of off-springs with desired characteristics: Learners learn from one another in group presentations and boost their confidence in contributing to group work.
Teaching and Learning Materials:
- * Simulations * Photos * Textbooks and posters on variation in skin colour hair texture and shape of nose
- * Fingerprints of humans etc. * Phenylthiocarbamide - PTC.
Assessment (3.2.1.AS.1). The document marks these depth-of-knowledge levels for this indicator: Level 2 Skills of conceptual understanding; Level 3 Strategic reasoning.