Like last year, I will begin the second semester of biology with the ecology unit. Many teachers leave ecology until the end of the year or teach it at the very beginning of the year, but I’ve found that it’s a good unit to begin the second semester with. After a semester of cells and genetics, the students find ecology much easier to comprehend. Also, our next unit is evolution, and the examples that I use in ecology to explain how species function in their environment lead nicely into explanations of why species look the way they do.
Since we live in the Central Valley of California and have no money for field trips, I take the students around the world with Planet Earth. For example, for our first lesson we talk about how ecology is the study of interactions between biotic and abiotic factors in the environment. I show this clip and have the students jot down the characteristics of the environment.
After the video, they decide whether each characteristic is biotic or abiotic and state how it interacts with the other parts of the environment. (There are always a few students who debate whether snow is alive…)
This strategy of introducing an idea, showing a video clip, and then discussing it works for most topics in ecology (predator-prey relationships, food webs, competition, community vs. ecosystem), but I’m still looking for a good way to teach nutrient cycles. It’s difficult to find a video showing invisible interactions like bacteria fixing nitrogen. Last year I just lectured about the cycles, but the students couldn’t find a reason to care. Nitrogen isn’t cute and cuddly like a panda. I’ll see what I come up with for this year.