12/18

This week, we discussed four common genetic disorders (cystic fibrosis, sickle-cell anemia, hemophilia, and Down syndrome). We spent time reviewing our genetics chapter on Tuesday and Wednesday, and took the chapter test on Thursday. When we return from break, we will discuss the structure and function of DNA.

Enjoy your two weeks off! I'll see you in 2010!

12/11

On Monday, students worked in small groups to practice using Punnett squares. On Tuesday, students participated in the "Face Lab." In this lab, students had to play the role of parents and flip coins in order to determine which traits would be passed on to their "child." This lab reinforced how alleles are passed from parents to offspring and how probability (in our case, flipping a coin) plays a major role in genetics. Students had to use the results from their coin flips to draw a picture what their "child" would look like. I will be hanging up these lovely (or not so lovely, in some cases) pictures next week. This week, we also discussed how certain traits were located on the X chromosome and that sex chromosomes determine our gender (XX for females, and XY for males). We used this knowledge to learn how to do X-linked Punnett squares. We spent time practicing these Punnett squares in small groups on Friday, and it seems like students are really getting the hang of it! Next week we will discuss a few common genetic disorders and take our Chapter 5 test (on Thursday).

12/3

This week, students were introduced to the basic principles of heredity and genetics. We looked into Gregor Mendel's scientific investigations with pea plants and did a "pollination" activity to see if our results matched up with his second experiment. On Wednesday, each student had the chance to observe their physical characteristics and those of our classmates in order to determine whether our classmates had more dominant or recessive traits. Out of the 10 traits we observed, we found that this year's 7th graders exhibit an equal number of dominant and recessive traits. On Thursday, we began using Punnett squares to determine all possible outcomes of a cross between two organisms. We will continue our work with Punnett squares next week, and we will begin to examine X-linked traits and Punnett squares.