Chapter 5: Genetics (Variation II)

Learning standard: 

Communicate about continuous variation and discontinuous variation

Lesson activity:

Hello everyone. Let us continue the lesson on variation. So, you already know what are the differences between continuous variation and discontinuous variation. Let us recap the differences.

Diagram 1: The differences between continuous variation and discontinuous variation

Now let us focus on factors that affect variation. There are 3 factors that can affect variation. The first one is genetic factor. Due to crossing over that occurs during meiosis process, the daughter cells produced will have a combination of genes from paternal chromosomes and maternal chromosomes. Mutation also can caused variation. The second one is environmental factor. For example, twins who have almost 99% similar genes; if they are separated into different environment, eventually they will look different in physical appearance in terms of style, attitudes or culture influences. Next one is adaptation. A person can be different when they have to adapt to their new environment in order for them to survive.

Diagram 2: Factors that caused variation

So, why variation is very important? Why do we need to be different from others? Do you want to have the same you?Or you want to be the only you in the world? Something for us to think about.

Diagram 3: Importance of variation

Ok students. Before you do today's exercise, watch this cartoon about genetic variation. Enjoy.

Practice
Answer the question below in a foolscap paper. Please leave comments if you enjoy your lesson today. Thank you students.

1. What is variation?
2. Give three examples of discontinuous variation.
3. State two factors which cause variation.
4. Why is the ability to roll one's tongue considered as a discontinuous variation?
5. State one important of variation.