While discussing homeostasis in biological systems, one of my biology students asked why humans could only survive with only a very narrow range of body temperature. Part of the answer is that the human body is a complex system, and the chemical reactions rely on enzymes that only work effectively within a narrow range of temperatures.
Worthington Biochemical has detailed (probably too much so for our purposes) introduction to enzymes: how they work, how they’re named, etc.
In particular, they have this useful graphical diagrams showing how enzymes have an optimum temperature and pH.
Enzymes work best within an optimum range of temperatures. Image from Worthington Biochemical.
Yesterday, Dr. Sansone was kind enough to lead my Biology class through a small mammal dissection (details here). He’d brought in five New Zealand White rabbits (2 male and 3 female) that had been raised for market by an Amish family in northern Missouri.
Over our two-hour class period, we had time to examine the organs in the abdominal and thoracic cavities in some detail. Students had been prepared with group reading assignments of the different organ systems based on the anatomy outline.
Dr. Sansone points out a rabbit’s ovaries. A kidney is visible to the lower right.
After the dissection we removed the pelts and froze them for later preservation. We also froze the carcases for later. I’ve convinced Mr. E. that cooking them would be a great interim activity. Mr. E. is a bit of an epicure, so it did not take much convincing.
Notes
Only one student declined to participate in the dissection for ethical reasons. About half of the class declined to observe the harvesting. Four students volunteered to assist in the harvesting, two of whom were not even in my biology class. They were seniors. One of them, P., had done it before and demonstrated the procedure for us.
Concept map for the study of anatomy. This diagram will be used for the introductory lesson.
Because we have the opportunity to get a few rabbits, we’re starting Biology this year with anatomy. In the first week, our discussions will be based around the rabbit dissection so we’ll be focusing on the systems where the organs are easiest to find: the fluid regulation/excretory, respiratory, cardiovascular, reproductive, and digestive systems.
This year I’m trying teaching pre-Calculus (and it should work for some parts of algebra as well) based on this concept map to use as a general way of looking at functions. Each different type of function can by analyzed by adapting the map. So linear functions should look like this:
Adapting the general concept map for linear functions.
You’ll note the bringing water to a boil lab at the bottom left. It’s an adaptation of the melting snow lab my middle schoolers did. For the study of linear equations we’ll define the function using piecewise defined functions.
The relationship between temperature and time on a hotplate. The different parts of the graph can be defined by a piecewise function. Graph by A.F.
Over the weekend I ran into this article from Planet Money/This American Life about a charity that just gives money directly to people. It should help to prepare my students for the Heifer International Ranch trip next month. It’s interesting to hear what people spend the money on; things like metal roofs and cows. Heifer gives cows and training instead of just cash. The article compares and contrasts the two approaches.
One of these days I’d like to put in a garden at school. Or maybe a few gardens. An indoor hydroponic system would be nice for the winter months, as would a greenhouse. However, the easiest thing to start with might be putting in some raised beds. To this end, the University of Santa Cruz’s Center for Agroecology and Sustainable Food Systems has detailed information in their Teaching Organic Farming & Gardening: Resources for Instructors manual.
