One of the things that I find challenging about teaching science is that it’s a subject for which I have great enthusiasm, but which I have only a lay knowledge of. After all, my formal training in science ended in college with intro to geology my freshman year.
I try my best to understand what I’m teaching, but I often discover things with the kids as we read together. This is a mixed blessing, of course. On the one hand, I’d love to know enough to be able to pick out and elaborate on anything and everything or to spot every error instead of just occasional ones. On the other hand, I know at least I’m modeling interest and enthusiasm.
We just hit up against a perfect example of this with biological classification. Nearly all the books and resources about this are outdated. In case you’re not aware, biologists have been busy totally messing up the classification system you learned in school. Now, instead of five kingdoms, we’ve got three domains. And while kingdom comes under domain, I found some interestingly conflicting sets of categories. Basically, I think what it boils down to is that they’re not totally sure yet, especially when it comes to the multitudes of tiny life forms out there.
So, what to do? We began with a pile of clip art of all kinds of life forms, from single celled organisms to mushrooms to polar bears. I asked the kids to come up with their own system of classification. They immediately came up with one worthy of the ancients. There were a few categories that showed that they knew things went together such as invertebrates, but many of the categories were things like, “things that fly” and “things that climb” and “tiny things.” I explained that this was exactly the sort of categories that the first scientists used to organize animals.
But then, I said, scientists looked inside animals and realized things – so, for example, in the “things that swim” category, the jellyfish doesn’t have a backbone so it belongs with the invertebrates, and the dolphin has live babies so it’s a mammal. So we divvied up the larger life forms and showed the basic kingdoms system.
But now, I said, scientists have new information. After a moment of discussion, the kids knew that was DNA. We talked about how that has changed our understanding of how everything should be organized. Mostly this has effected the smallest life forms, but it has also effected others. For example, at the zoo the other day, the volunteer told us about how the orangutans had been reclassified into two species not too long ago, meaning that the zoo can no longer let some of them breed that they had before.
As we took notes, I did the best I could, pointing out how much these categories may change in the near future. And I hope that this sense of change and discovery with science makes it more interesting and compensates for my own lack of information and the outdated nature of many of the textbooks. At least for me, this is what’s so interesting and fun about science. We get to see how our understanding of the world changes and deepens.