The last set of guided reading questions has been updated and is ready to go. The end of the year is in sight. I'm excited, since this year we'll actually finish the AP Bio curriculum by the exam. This means we get to do a fun (in a morbid way) Ebola unit for the last three weeks of the year. Anyway, for the human unit we focus on the nervous, endocrine, and immune systems and embryonic development. I'm going to try the Pom-Pom Potential activity from Learn Genetics Utah and possibly Jumpin The Gap. Then we'll look at the Nerve Cell Communication activity from the Life Sciences Learning Center of the University of Rochester. We also do a fun lab looking at circulation in goldfish tails and the effect of epinephrine on the circulation. Still looking for a good immune system lab or activity.
This week both of my classes (high school level Biology and AP Biology) did a termite lab. I love both of these labs. In general, I'm not a big fan of bugs. Dissecting grasshoppers grosses me out. But termites--I just tell myself they're little white ants. Fortunately, you are supposed to avoid touching the termites, so we use paintbrushes to move them around. No complaints here about that! They're pretty low maintenance too. I order a 25 pack of worker termites from Carolina. Both years I've ordered them, Carolina has been generous with the termites, and we've had at least 40 in the package.
In HS level Biology our termite lab is part of our evolution unit. This lab emphasizes the adaptations of the termites and how that helps them to live to reproduce--increasing their fitness for their environment. But to me, the real emphasis of this lab (and AP Bio's) is experimental design. For my middle school/high schoolers this lab provides a whole lab period of design/evaluate/redesign.
Each lab group starts with a petri dish with a piece of paper that I've instructed them to draw a closed shape on with a Paper-mate red pen. I give them three termites and have them observe for a few minutes. Then they must decide on a hypothesis about why the termites behave the way they do and test it. Before they test the hypothesis, they write out the independent and independent variables and the controls they will use so they are only testing one variable at a time. Then students carry out the experiment and observe. After observing for a few minutes, more questions arise and a new or updated hypothesis is formed. The process repeats. Our goal is at least 4 hypotheses tested.
Each time they go through the process, they start to see how their design can be improved. We can talk about how scientists in real life are continually working to improve the design of their experiments and fine tune their hypotheses. The process gets them thinking in a different way than cook book experiments do. For many labs, this process just takes too long, but this one goes fast enough and is simple enough to refine several times in one period.
In AP Biology, this is our animal behavior lab. In this lab, we also discuss taxis and kinesis. We start the same way as the other lab, with the petri dishes, but then they have to develop a hypothesis to test using the choice chambers. They also have to perform a chi-square analysis for each set of results to determine if random chance brought the termites to the chambers that they went to, or if some other factor was in play. We had some great discussion about experimental design with one group who was testing different colors of pen. After their first trial, they realized that maybe the shapes were too far away from each other for the termites to even realized there was another side. Their second round included drawing the shapes closer together. They improved on their experimental design.
The source of the idea for this lab came from the book, Biology Inquiries: Standards-Based Labs, Assessments, and Discussion Lessons by Martin Shields. I developed a sheet that I give my HS Biology kids and then I also outlined requirements for a lab report for my AP Bio kids. I'll include both below.
We are coming up to our ecology unit soon, so I've been revising our guided reading notes for this next-to-the-last-unit for the year. We actually start this unit with animal behavior and I pull out the termites for us to experiment with. This unit also includes estimating population sizes--with a fun capture/recapture lab with "bean" organisms.
Last year I went to an AP Biology workshop and the presenter shared several resources with us. One of the resources was The Great Clade Race by David W. Goldsmith. This activity first appeared in The American Biology Teacher, 65(9):679-682. 2003. Here is one link to that article. There are several other resources associated with the Great Clade Race here. Our presenter also shared a set of student questions for the students to use as they walked through the activity. I reworked that sheet to better flow with my class. Here is my adapted version of the student sheets.
Each student lab group receives a huge piece of paper, a set of markers, and a set of racer cards that have been stamped along the pathway they take in the race. Students use the cards to determine what path each racer took to get to the finish line. I encourage each group to plan their race course out on scrap paper first, and then move on to the big paper when they're happy with their map. Initially, students tell me this is impossible, but after some struggle, they all figure it out. All the lab groups draw the race out on their huge sheets of paper and we compare them. At first they exclaim that theirs is different from another, but then they realize the paths are just rotated around a branch point. This leads into the understanding that cladograms can pivot at branch points and still be the same cladogram.
Once they're feeling fairly confident in their cladogram skills, we add another racer--who of course doesn't easily fit within the original paths of the race. Eventually, they figure out that they have to draw in a checkpoint a second time to get him out of the race--an analogous trait!
Then we're ready to move onto classifying organisms, and so they move onto their clade critters. In this part they also make a table comparing the characteristics and use it to help them make their new cladograms. I love how this lab pulls in so many concepts in a step-wise manner.
