February 17, 2013
We have been very busy in class this past week collecting data that will be used in our fruit fly lab reports that will be due near the end of our genetics unit.
Events of the Past Week
Monday - Class began with an explanation of the differences between the formation of sperm in males (spermatogenesis) and the formation of eggs in females (oogenesis). We then spent some time reviewing our meiosis material in preparation for our meiosis quiz on Tuesday. Homework was to study for the meiosis quiz that we took on Tuesday.
Tuesday - Periods were shortened on Tuesday due to the Late Start Day. The quiz took most of the class period, but there was time to introduce our fruit fly (Drosophila melanogaster, for you science geeks out there) computer software. The students learned how to use the program, and were given their groups for the project. I attempted to group students according to their math levels and grades, such that each group should have at least one strong math student in it. Genetics is a very mathematically based unit, and this particular project requires quite a bit of math skill, so this seems to be the best way for me to group students. I created the groups for all four of my classes.
Wednesday - The students began using the computer program to collect data for their projects. They were given two different fruit flies, each with a different mutation, to breed. They then counted 100 of their offspring, classifying them as male or female, and also looking for any mutations in the flies.
Thursday - The students continued collecting data, first by breeding 2 of the offspring from their first generation and counting 200 of their offspring, then by breeding two different males and females and counting them through two generations.
Friday - We finished collecting data, and the students then handed their data over to me so that I have a copy of it. This will prevent them from changing their data later in the genetics unit after they have determined how their traits are inherited. Class periods were only 28 minutes on Friday due to an early dismissal.
Monday - No school - PRESIDENT'S DAY
Tuesday - Students will be introduced to how to predict the results of a breeding between two individuals where we look at only one trait being passed down to the next generation. These types of problems are called "monohybrid" crosses. They will also be introduced to a special type of cross called a "testcross", and a type of inheritance called "incomplete dominance." Homework will be to complete Problem Set 1 on a separate piece of paper.
Wednesday - Problem Set 1 will be collected. 5 of the 10 problems will be graded. Each problem that is graded will be worth 2 points, with one point coming from the work that is shown being accurate, and the other point coming from having the correct answer. If an answer is given with no work, then no credit will be given for the problem. Since it is homework, without any work being shown, I have no way of knowing if the student just asked for the answers from a friend, or if they actually took the time to do the work.
After collecting Problem Set 1, the students will be introduced to "dihybrid crosses," where they will be determining the expected outcomes of a cross between two individuals where we look at two traits being passed down at the same time to the next generation. Homework will be to complete Problem Set 2 on a separate piece of paper.
Thursday - Problem Set 2 will be collected from the students, with 5 of those questions being graded at 2 points each. After being collected, the students will be given the opportunity to ask any questions they may have from Problem Set 2.
We will then be looking at traits that are carried on the sex chromosomes (specifically, the X-chromosome). This type of inheritance is called X-linked, or sometimes sex-linked, inheritance. The students will then be given Problem Set 3, and will complete up through and including number 7 on a separate piece of paper. Any problems not finished will be completed for homework
Friday - At the beginning of class, the students will be taking their first genetics quiz. The quiz will cover the topics of monohybrid crosses, incomplete dominance, and test crosses. In addition, the students will be expected to know any new vocabulary learned during the course of the week.
When everone finishes the quiz, we will learn about pedigrees. Pedigrees are family trees that trace the inheritance of a particular trait through a family. After looking at a few pedigrees, the students and I will look at the inheritance of hemophilia in Queen Victoria's descendants. We will look at how the inheritance of this X-linked recessive trait led to the rise of communism and the Cold War between the United States and Russia (we might be stretching it a little bit, but we'll have fun with it)! Homework will be to complete the worksheet "Human Pedigree Genetics" on a separate piece of paper.
Graba Geek of the Week
This week's Geek of the Week is Matt McCabe, who earned a perfect score on his meiosis quiz in the beginning of the week. Fantastic job, Matt!