Using the model of a Punnett Square to predict offspring ratios

Objectives ► Objective 1: Students will know that chromosomes have genes that control the phenotype (appearance) of organisms ► Objective 2: Students will calculate the percentages of various types of potential offspring based on a simple dominance model and using a single trait. ► Objective 3. Students will extend the model of the Punnett Square in order to apply the concept of simple dominance to new traits.

Interactive Concept Building Attributes: ► “just-in-time” instruction XXX-----XXX ► Teacher-student & student-student discourse Goals: ► Help students interpret, understand, synthesize info they have been working with (build on their experiences & language) ► Facilitate discussion with Questions & new info (integrate student language & encourage cross-talk) ► Provide a bridge to scientific way of talking/thinking ► Challenge students to return to activity armed with new knowledge

“Will your kids be able to roll their tongues?”

Sperm + Egg = Offspring ► We have been talking about the idea of sperm and egg getting together to create a new life. We know that this happens in both plants and animals. In animals, the male contributes the sperm, and the female contributes the egg. In plants, the male part of the plant contributes pollen, which acts like the sperm, and in the female part of the plant is the egg.

Mysteries & Inheritance ► If we look at brothers or sisters who all come from the same parents, do these brothers and sisters all look exactly the same? So are we not clones of our parents? ► What are some differences between brothers or sisters who come from the same parents?

More questions ► If you have a mother who is 5 feet 5 inches tall and a father who is 6 feet tall, and they have four children, how tall do you think they should be? All the same? ► Is it possible for a child to end up shorter than both parents? Or taller than both parents?

And what about… ► Have any of you seen a person who looks like they have the traits of one of their grandparents but not the parent, like the traits skipped a generation? ► Do any of you have traits more similar to your grandmothers or grandfathers than your parents?

To begin to understand how these kinds of traits can be inherited, we have to go back to the idea of the sperm and the egg contributing to who we are.

23+23  46 Chromosomes Female & Male

► These paired chromosomes are made up of thousands of sections called genes. Each gene controls some kind of trait, like color of hair, or color of eyes, or contribute to height. There are about 100,000 genes There are about 100,000 genes that make up the human body. that make up the human body. MotherFather

What is interesting is that we can tell a little about what kind of genes we have by observing various traits in ourselves. Which form of the gene is wins? loses? Free (F)Attached (f) Roll (R)Not Roll (r)

Beaker Babies ? f F F or F f

F f F f Male FemaleFemale Punnett Square F F F f f F f f Phenotype Ratio (what shows): 3:1 POSSIBLE Combinations of Genes

rrrrrrrr r r r r Male FemaleFemale Phenotype Ratio (what shows): 4:0 Now to answer our question for the day…

Tasks for the day: ► 1. If you can roll your tongue, what do you know about the two genes that you have inherited? Explain. ► 2. If you cannot roll your tongue, what do you know about the two genes you have inherited? Explain. ► 3. Using a Punnett Square, can you show if it is possible to have another and a father who can roll their tongues, but have children that cannot roll their tongues? Explain. ► 4. Using a Punnett Square, can you show if it is possible to have a mother and a father who cannot roll their tongues, but have children that can roll their tongues? Explain. ► 5. Extra challenge: Create a Punnett Square that incorporates not one, but two traits (tongue rolling AND earlobes). Hint: You will need a total of 16 cells in your Punnett Square. Tell about the different kind of offspring that are possible.

So what did we learn today? ► About ourselves ► About genes ► About inheritance ► About Punnett Squares ► About science

Where are we going? To study the particular diseases that can be inherited & what those patterns of inheritance are…

How did your partner help you learn today? What’s something you did well together? Say thanks & something you appreciate about them.

For your microteaching… ► What big ideas & their related concepts are best suited for this strategy? ► What inquiry activity might they be doing as a context for using this strategy? ► How can I have the students participate in creating the bridge to this scientific concept?

Female- Body Cell Chromosomes

Male- Body Cell Chromosomes