Friday, December 04, 2009

There's Just Something About a Punnett Square

This week we started a new unit on genetics.

I absolutely love genetics. It's a totally cool subject and there are so many activities that you can do with it that I could, if I had the time, spend an entire month on the subject. (Unfortunately, I don't because we have that Carved In Stone Deadline of the Very Big Deal Government Mandated Test looming on the horizon). has been my experience that this is one of those units where you will actually see a light go on over a kid's head when they all of a sudden get it. We'll be going over (and over and over and over) how to do a Punnett Square (and better yet, how to interpret the results) and you'll hear a kid exclaim, "I get it now!" and off they go, crossing genes left and right. It's a lot of fun.

When the kids actually listen, pay attention and retain anything you've said over the past, oh, three or four days. Or better yet - actually learn their vocabulary words so they know what in the heck we're talking about.

We are using (over and over and over and over) the words genotype, phenotype, dominant, recessive, homozygous, and heterozygous. We have written these in notes, given example after example, worked problem after problem, and used these words over and over to the point that I'm seeing them in my sleep. I've had the kids throughout each class period raise their hands to indicate "got it", hand clenched for "kinda got it", and thumbs down for "completely lost". By the end of each period, all hands were in the "got it" range. So you'd think, hey, we're home free, right?


Some of them are still absolutely clueless. (The ones, interestingly enough, who rarely do work and can't shut up.)

I teach our study skills class during one of my planning periods on Thursdays and I used that time to - once again - reteach the subject. I had Mrs. Aide in there with me (this was a repeat for her as she had just come from Mrs. Eagle's study skills class first period where she did the exact same lesson - we do collaborate after all!) After I finished the review I gave the kids an activity pack called Zork Genetics (developed by Rodger Moore from Wooster High School in Reno, Nevada - go here for a link to the pages; you'll have to scroll down a bit) which is a ton of fun and really, really easy. The idea was to walk them through the first problem, put them in pairs, have them solve the next problem, class discussion, pair up again, and so on.

Except they couldn't even get how we did the first problem.

Homozygous? Didn't have a clue (and couldn't even figure out how to look on the handy little table and read down the "homozygous" column for the answer). Heterozygous? Even worse.

I was aghast. Mrs. Aide was shaking her head. These were the same kids who assured me that they "got it", the day before. Today they were completely blank. Utterly unable to answer a single question.

"So, just a quick question," I asked. "How many of you actually did your vocabulary cards Monday and started studying them?"

They blinked. Not a hand went up.

"So, you have no clue what I'm talking about?"

More blinking.

"Any suggestions?" I asked them.

Polite Boy raised his hand timidly. "I think we need to learn our words, Ma'am," he said.

"I think you're right," I answered. "Because if you don't know what they mean, you're never going to figure out what's going on."

It's going to be a long two weeks...


Anonymous said...

I know those blank stares and it is so frustrating.

Hopefully you will more and more of those "I got it!" moments.

Darren said...

It's fun to introduce basic probability with Gregor Mendel and his experiments....