Tag Archives: Year 10

Fun with Fungi

OK, I take it back; WordPress is great – I’m just being more than unusually incompetent in trying to figure it out. I think (touch wood) that I’m getting the hang of it…

And golly, the burblings are being read all over the world! OK, so 1 hit in Australia (hello, Melissa!) and one hit in America (hello, Julie!) doesn’t quite equate to global domination, but it’s a start….

Back to the plot.

iGCSE classification.

Ugh.

Doesn’t get much duller than having to learn the defining features of the 5 Kingdoms. It’s rather like conceding to Rutherford that, yes, all science is either Physics or stamp-collecting, a grim throwback to the days when all Biology could do was describe and classify things, because it was all far too complicated/small to actually understand. It’s a challenge, I think, to make this topic interesting.

The first thing I do is break it all up; schemes of work don’t have to follow the exact order of the specification, and it’s a good tactic to disperse the duller stuff across the terms and years. So the Year 9s can compare plant and animal cells under the microscope and observe some of the obvious differences – a homework where a plant and animal cell meet in a bar and have an argument as to which is the superior cell gets them to use the information. Comparing a student to a geranium from the perspective of an alien scientist draws out the other points of comparison.

Bacteria and protoctists? Save them until Year 11 when they can meet them in the context of disease.

But Year 10 is when they meet yeast as they learn about respiration so it seems a sensible time to learn about yeasty things. It starts easily enough with a picture of a mushroom. What’s this? A mushroom. Well done. How would you classify it? It’s a bit like a plant – sessile, multi-cellular – but it can’t be a plant with that chitin cell wall and the lack of chlorophyll. Hang on, lack of chlorophyll? That means it must be…. anyone remember the term?…. heterotrophic! But how can you be heterotrophic if you can’t run after your food (which is the whole point of not having a cell wall!)?

This is where it gets hard. A mycelium of hyphae? A who? A what? I can still remember that awful feeling of blank incomprehension that usually swept over me in French lessons, but reared itself in Biology when I first encountered these terms. Without context, without function, it’s just meaningless vocabulary. So they need to see it and understand it.

Here are three ideas, not mutually exclusive. One, suggested by Bill, is to carve up a pumpkin about 4 days before the lesson. As he says, nothing does fungal growth quite like a pumpkin. You get to pull it apart in front of the students to reveal the great fluffy mass within the oozing, pulpy ex-pumpkin. Yum. Another, discovered serendipitously, is to just leave an agarose gel in the fridge for 3 weeks. The inevitable fungal spores grow into glorious 3D stars, captured within the gel, as the hyphae snake out into the gel. They are startlingly beautiful.

Or (and this is my personal preference), you can start by asking them if they’re hungry (always a good question for teenagers). Yes? Right, come over here! Lots of food over here! They cluster eagerly around the big box – but are rather disappointed when I reach in and pull out a toilet roll. No? No-one wants to eat a toilet roll? But why not? It’s full of energy! Burn a few sheets to demonstrate presence of energy in toilet paper. Not tempted? Hmmm. But what’s paper made of? Wood. Which comes from? Trees. Which are? Plants. And plants are made of? Plant cells. So which part of a plant cell do you think paper is made of? The cell wall. Which is made of? Cellulose. Aha, what’s cellulose made of? They probably don’t know, so point them at the helpful cellulose models made by your Year 12s (next week for details on this!). Cellulose is just hundreds of glucoses joined together. And glucose is a? Sugar.

So, why can’t you eat toilet rolls?

And here’s the chance to revise digestion, and enzymes, and enzyme theory.

So, even if we did eat a toilet roll, it would have little nutritional benefit because we can’t digest it, we don’t have the right enzymes. But I’m going to introduce them to an organism that can…

At this point they stuff their own toilet roll with a fungal spore mix from http://www.ncbe.reading.ac.uk/NCBE/MATERIALS/MICROBIOLOGY/oyster.html.  This then goes on the back burner as we do a few more respiration experiments, or set up the fast plant experiments, or whatever. A few weeks later, we fish them out and take a look.

OK, a word of warning. It’s a pretty strong pong! Think rotten Stilton with a strong overtone of even more rotten Camembert. But! What can they see? How would they describe it? The toilet roll is full of wispy fluffy hairs. What’s going on? And here you can talk about hyphae and extra-cellular digestion and how the whole fluffy mass is the mycelium. Words to describe what they can see, a function to fit to the new vocabulary, it all makes sense.

A few weeks later, the toilet rolls sprout an amazing crop of oyster mushrooms, and we go up to the kitchens to fry them in butter and garlic. And isn’t it amazing??? I mean, just think about it!!!! Here’s an organism that can convert a toilet roll into oyster mushrooms! Saprophotastic!

Even Harry Potter can’t do that.

Sylvia Plath mushroom poem can be found here http://genius.com/Sylvia-plath-mushrooms-annotated with some nice pictures of fungi… would make a lovely addition to the lesson