1. Inquiry 12.5 and 12.6 Prepare for a Warm-Up
Take out your yeast lab and pink dihybrid cross worksheet
Turn in your purple (or white) probability (p. 5, 6 only)

2. Warm-Up 12/5 and 12/6
Tall plants are dominant to short and round seeds dominant over wrinkled. Write the genotypes of parents who are: a. Heterozygous tall and round b. Homozygous short and homozygous wrinkled Write the phenotypes of plants with these genotypes: c. ttSs d. TTss

3. Learning Targets
I can determine the probability of offspring inheriting multiple traits using a dihybrid cross.
I can model and explain the process of chromosomes being separated into gametes in meiosis

4. Your Turn
Finish the pink Dihybrid practice WS (#4 is optional)

5. Yeast Lab
alpha2
(red)
alpha3
(cream) A2 A3
First set of parents
Second set of parents
Today: Make a sketch (in color) of your results Write your CLEVR conclusion

6. Good Results (from last year!)

7. Claim, Evidence, Reasoning
Yeast Lab Conclusion CLAIM: Make a claim about color dominance. EVIDENCE: Give number data to support your claim. Use percentages from your Punnett Square cross on your petri dish. REASONING: Why did you get the results you did? Use genetic terminology to help explain. Maybe use a Punnett Square? SELF EVAL: Color code (highlight or underline) your CER (see the bottom of your lab sheet)

8. Meiosis!

9. Meiosis Meiosis is the process of making gametes (sperm and eggs)
Gametes have half the number (23) of chromosomes of the original cells (46)
Meiosis turns one 46 chromosome cell into four 23 chromosome cells
See any math problems here?!!?

10. Meiosis: How it Happens23 46
Chrom 23 46
Chrom 92
Chrom
Interphase
(Double
Chromosomes) 46
Chrom 23
Meiosis I 23
Meiosis II

11. Guided Reading
Read pages
Complete the guided reading sheet

12. Steps that Increase Variation
Crossing Over in Prophase I
The way sets of 4 chromosomes line up in Metaphase I

13. After Meiosis
A sperm cell and egg cell, each with 23 chrom., fertilize to form a zygote. + = The cell of the zygote divides/grows to become an embryo, and eventually a baby! The zygote has 46 chromosomes! 23 23

14. You must half the number of chromosomes to get sperm + egg = 46!
Muy Importante!
Meiosis is necessary because if you merged two cells with 46 chromosomes each to make a baby, you would get a 92 chromosome mutant!
You must half the number of chromosomes to get sperm + egg = 46!

15. Why Did Meiosis Evolve?
Sexual reproduction increases the genetic variety in a population
Greater variety = stronger population (toothpick fish!)
Sexual reproduction always involves the combining of genes from two different organisms to form a zygote
Plants, animals, fungi, protists…

16. Asexual Reproduction
Asexual reproduction also exists in simple organisms, but makes a clone of the parent
This DOES NOT increase genetic variety, but does take less energy
Some organisms do both types of repr.
Potatoes form sprouts that are clones of themselves.
They can also make seeds/sperm to reproduce with neighboring plants.

17. Meiosis Modeling
Get a partner, a whiteboard, two colors of playdough, and a pen
Copy the blank diagram from the whiteboard
You need four chromosomes to start: two of one color (from mom) and two of another (from dad)
Model them from the original cell to the four gametes
Show crossing over in Prophase I and lining up in Metaphase I