Talking Teaching

March 10, 2012

a map for ‘basic biology bits’

Students in my first-year bio class have quite varied backgrounds in terms of their prior learning in biology. I’ve had a little survey running on our Moodle page in the lead-up to beginning to discuss plants: roughly 1/4 of them didn’t take year 12 (6th form) bio; 1/4 did, but didn’t study plants; and most of the rest both studied year 12 biology and learned about plants. (For readers outside of NZ, year 13 is the final year of high school.) This is going to make teaching about plants – which occupies not quite half of the paper, quite ‘interesting’. It also means, of course, that 25% of the class don’t have any formal leaning in biology as a separate subject at all: something that my colleagues & I need to keep in the back of our minds in our teaching.

And of course, even those who report having studied something in school may not actually remember it in any meaningful way, in the sense of having accurate conceptions about the topic. However,  the misconceptions that they may have in lieu can make expanding & correcting their understanding quite tricky. For this reason, a few years ago I began starting the new semester with a class called ‘Basic Biology Bits’ – pop quizzes & discussion around a few key ideas that many students appeared to be having trouble with. Feedback from the class was positive, so I’ve kept that in the curriculum.

However, having read & blogged about visual curricula, I realised that just dishing out a set of apparently unrelated concepts probably didn’t make a lot of sense to the students, even if they were gaining an enhanced understanding of the concepts in isolation. So now I have a little map to show them where we’re heading, & I thought I’d share that here (since my last post seems to have attracted so much interest, lol).

We started off with an idea that everyone agreed with – that living things are made of cells. Cells are very small, & I wanted them to think about why this might be:

This gave the opportunity to talk about just how ‘small’ is small & to introduce the units of measurement (micrometres) that they’ll be using with their microscope work in the lab. I find a lot of bio students tend to be quite maths-phobic & a little gentle intro to these units & also to the idea of converting between them will hopefully be useful when they come to work out the size of the things they’re seeing down the microscope. And the ‘why’ question meant that we could talk about diffusion & osmosis & why multicellular organisms need some sort of transport system.

We’d talked a bit about plants being autotrophs in a previous class, but I wanted to give a heads-up that they’d be learning more about photosynthesis in another paper. Turned out not all of them were familiar with writing or interpreting a chemical equation, so showing

CO2 + H2O + light energy –> C6H12O6 + O2

was quite useful as a means of signalling that they’d need to become familiar with the basics of chemical formulae. (Also, it turned out during the body of the lecture that I’d got a mistake on the relevant slide. Someone was brave enough to point this out, & I thanked him & took the time to say that this was good; students shouldn’t be afraid of asking if they think someone’s made a mistake, just as it’s important to ask if they don’t understand something.)

A few years back I was rather taken aback to discover a particularly common misconception among our first-year bio students: the idea that plants photosynthesise, but don’t respire. Ever since I’ve taken the time to point out that all living cells respire, albeit not necessarily aerobically. I use a couple of pop quizzes on the processes that cells might need energy to carry out. And we also talk about ATP as a carrier of energy – and why cells might need such carriers.

(Don’t know how I managed to include that line just above!) It’s interesting to think about respiration & photosynthesis in terms of the carbon cycle, something that we’ll be considering in more depth towards the end of the semester.

 And finally, reminding them of the role of DNA in controlling all these goings-on. (That 25% of the class who didn’t study biology at the senior high-school level are going to need a lot of help in this area!) When we looked briefly at mitochondria & chloroplasts I noted that both organelles have their own loops of DNA – & asked why some mitochondrial genes are located in the nucleus & not in the mitochondria at all. A very interesting discussion ensued.

Teaching like this is probably more work, in some ways, than a traditional lecture. It certainly can demand more of the lecturer. But I firmly believe it provides a much better learning experience for the students! The thing is, you just need to signal what you’re going to do from the start – and explain why. “I’m going to be teaching in this way because science education research clearly shows that it significantly enhances learning outcomes for students.” That way, we’re all in the same boat & paddling in the same direction :-)

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