Basic Science and Technology - Junior Secondary 3 - Family traits

TERM: 1^ST TERM

WEEK: 3

CLASS: Junior Secondary School 3

AGE: 14 years

DURATION: 40 minutes each for 2 periods

DATE:

SUBJECT: Basic Science

TOPIC: Family traits

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

1. ) Define family trait
2. ) Discuss Gregor Mendel’s experiment
3. ) State the importance of family traits
4. ) Discuss the concept of blood group and genotype

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

INSTRUCTIONAL MATERIALS: Recommended Basic Science textbooks for Junior Secondary School 3

INSTRUCTIONAL PROCEDURES: PERIOD 1-2:

NOTE

FAMILY TRAITS

Family trait refers to a characteristic or feature that is passed down from one generation to another within a family, usually through genetic inheritance. These traits can include physical attributes such as eye color, hair texture, and height, or even certain health conditions and predispositions.

Gregor Mendel’s Experiment
Gregor Mendel is known as the father of modern genetics. His experiments with pea plants in the mid-1800s laid the foundation for understanding how traits are inherited. He studied how characteristics like seed shape, color, and flower position were passed down through generations. Mendel's key discoveries were:

• The Law of Segregation: Each organism has two alleles for each trait, one from each parent, and these alleles segregate during reproduction, so each offspring gets one allele from each parent.
• The Law of Independent Assortment: Alleles for different traits are inherited independently of one another.

Importance of Family Traits
Family traits are important because they help to:

• Understand genetic inheritance and how certain diseases or conditions are passed through generations.
• Track family health history to predict the likelihood of inheriting certain traits or conditions.
• Identify genetic markers that can inform medical decisions, especially in terms of prevention, diagnosis, and treatment of hereditary diseases.

Blood Group and Genotype

• Blood Group: The human blood group is determined by the ABO system, which categorizes blood into four main groups: A, B, AB, and O. Blood group inheritance follows Mendelian principles. For example, a person with type A blood can either be genotype AA or AO, and type B can be BB or BO. Type AB blood is the result of inheriting A from one parent and B from the other, while type O requires two O alleles (OO).
• Genotype: A genotype refers to the genetic makeup of an organism—specifically the alleles inherited for a particular trait. The genotype determines an individual's potential for traits like blood group, eye color, or susceptibility to genetic disorders. For example, the genotype of someone with blood type A could be either AA or AO, and this determines their physical characteristics. The genotype of an individual is crucial in understanding the hereditary nature of traits within families.

EVALUATION:

1. What is the difference between a family trait and a genetic disorder? Provide examples of each.
2. Explain the significance of Gregor Mendel's laws of inheritance in the study of genetics. How did his experiments with pea plants lead to the understanding of dominant and recessive traits?
3. How do family traits influence the likelihood of inheriting certain characteristics or conditions? Give examples of traits that can be inherited from parents.
4. Describe the concept of blood groups. How are blood group genotypes inherited, and what is the role of blood group compatibility in medical procedures like blood transfusions?
5. What is the relationship between genotype and phenotype? Provide examples to illustrate how an organism’s genotype affects its physical characteristics (phenotype).

CLASSWORK: As in evaluation

CONCLUSION: The teacher marks their books and commends them positively