Tag Archives: hamsters

The hamsters are amazed

My Year 7s return from a week long residential in deepest Somerset to start the final topic in their completely re-written Year 7 KS3 Scheme of Work. I’m quite excited about this, but also slightly nervous. As always with a new idea, there’s the lurking anxiety, will it work?

It’s Biology’s turn and I’ve decided to chuck out the flowering plants. They get to do this in Year 9 as part of their iGCSE and, frankly, you can have too much of a good thing. Plus, while there are fun things to do with pollen grains/tubes and dead nettle dissection and trying to address the whole bizarre concept that flowers are SEX ORGANS and that, yes, plants HAVE SEX, and hay fever is caused by… but let’s not go there…. it’s not really a topic that lends itself to investigative experimental question asking. It’s much more from the “here-are-lots-of-strange-words-and-weird-structures-and-you-need-to-learn-them-for-the-exam” school of information delivery, a throw-back to the days when all science really was just Physics or stamp collecting. Biology has moved on from just describing stuff; so should we.

So I’ve turned to an area very close to my heart, one I did my PhD in, and one that has been brutally stripped from the new A-levels – Animal Behaviour. After all, it they’re not going to study it anywhere else, they can do it in Year 7. Plus, cunning laugh, it allows me to put my baboon behaviour resource firmly into the Year 7 curriculum. More on that in a future burble. Today was just the introduction, and it’s back to the hamsters.

Quick review with accompanying pictures:Introduction to hamsters with notes

What’s this?       A hamster!

Where does it live? In the desert! The Syrian desert!

What’s it like in the desert, the Syrian desert? Hot, cold, dry, exposed, sparse food.

How on earth does a hamster survive in such an extreme place?

They’re very good at this. Lots of good ideas on camouflage and burrowing and cheek pouches and being nocturnal, having good sense of smell and so on. Excellent. They are children of Attenborough. Let’s focus on the behavioural adaptations.

I get them to sit in a closed circle, on their knees, no gaps. I then plonk the docile furry bean bag that is Herbie the hamster into the circle. I tell them to watch what he does. How is this behaviour helpful for surviving in the desert?

It works really well. They love seeing Herbie, they all get a chance to stroke him as he goes round, and they’re perceptive. Herbie is exploring, Herbie is sniffling, Herbie likes tunnelling into gaps. This all makes sense. What else? It’s so obvious that it takes them a while to see it, but eventually they do – Herbie sticks to the edges – he never ventures out into the middle. Again, they instantly see why this makes sense for a small, edible organism foraging in an exposed environment.

So that’s the introduction. We’re going to be investigating animal behaviour and why animals do what they do – how does it help them survive?

I then introduce the idea of mazes. Can they think why it’s easier to investigate behaviour in a laboratory setting? Brief discussion on this, as I want them to get started on their project. Right, here are the kind of questions you can ask with mazes.

In groups of 4, I tell them to decide on a question – one of the ones I’ve suggested, or one of their own, and then build a maze to test it. They are VERY happy with this! Year 7s, cardboard, scissors, sellotape, the chance to make something and then put a hamster into it…. I haven’t seen them this happy since they made apple juice in the autumn term.  They’re off and running.

Of course, being Year 7s, the excitement of maze building might distract them from the scientific question I want them to ask. Sure enough, a couple of the groups haven’t quite thought it through. There’s some nice ideas about hamsters and smell, and hamsters in the dark vs hamsters in the light, but they’ve not narrowed it down to a simple, testable hypothesis. It’s the price you pay for being open ended. I like the excitement and motivation that ownership of the project gives the girls, and they can generate some superbly original ideas, but they will need quite a lot of support along the way. It’s important to keep circulating, to keep talking, to keep asking them questions.

We talk about some of the options. How could they improve this? What are they going to measure? They start to become more focussed. The other groups are fine – they really seem to have grasped the idea of simple, controlled experiments. How on earth is this possible???? They haven’t written anything down all year!!!! So, do hamsters get quicker at finding their way through a maze – this group is building a magnificently complicated maze, know exactly what they’re doing and have taken on board ideas of repeats and controls. Wonderful. Another group is testing food preferences and is building an appropriately simple T-maze. A third is seeing if turns are made at random, or whether there’s a pattern – does turning left make the hamster more likely to turn right next time. Excellent.

Best of all, and one of my Key Performance Indicators (aarrrghhhh) of a successful lesson, they all look surprised and rather disappointed when I tell them it’s time to clear up. Is that really the end of the lesson? How has it gone so quickly?

The actual experiments take place on Friday….

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Co-operative pregnancy

The briefest of burbles this week as we’re setting up the Year 12 Practical Skills Assessments – 38 students – and it’s all a bit manic.

So, pregnancy testing kits. Even I would not ask for a student volunteer to donate urine to show how they work – finding out that you’re pregnant, whether it’s a moment of life-affirming joy, or an unmitigated disaster, is not something that should happen in a Biology lesson. Mind you, I would have no problem asking a volunteer to use a fertility testing kit – and several brave girls over the years have done so.

I did test the urine of the class female hamster (Hettie)

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with a pregnancy testing kit, as she had recently mated with the male (Herbie)

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and we had high hopes of baby hamsters. The test came up negative but, which turned out to be correct, but we still don’t know if HCG (Hamster Chorionic Gonadrotrophin) is sufficiently similar to HCG (Human Chorionic Gonadotrophin) for the test to work if she was pregnant. Maybe in the summer term when Hettie and Herbie will meet again…

Anyway, pregnancy testing is on the OCR A2 spec. How to teach it? Specifically, how to teach it so that they learn how it works, rather than telling them how it works so that they then have to go away and learn it?

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I started by showing them the positive test for George, our youngest son. There he is, bless him, George’s first communication with the outside world, a little message saying, “I’m here! Look after me!” I still look on this as faintly miraculous. I give them a little bit of human detail – we had hoped for a girl, 3rd time round, but on the 20 week scan, along with the bones and kidneys and brain ventricles and beating heart, there was another structure visible that could only mean one thing, another bloody boy… A few tears in the carpark afterwards… but once George had actually manifested himself as George, we obviously wouldn’t change a thing.

But how does the actual test work?

I set it as a kind of Dragons Den/The Apprentice/Young Enterprise exercise. I asked them to imagine they were the development team at GSK and you’d come up with a brilliant idea to invent a pregnancy testing kit. Make millions from grateful women the world over! And then told them to invent it. From scratch. No research allowed.

It was joyous. They quickly decided that they needed to look at it from the consumer’s point of view as well as the biological point of view. What would the customer want? Has to be reliable and easy to use. So urine rather than blood. Something in the urine that is uniquely associated with being pregnant. That means it’s also got to be small enough to get through the basement membrane (i.e. molecular mass < 69,000 in the kidney.

At this point I provided a bit of scaffolding – the molecule you’re looking for is HCG. Released by the embryo very early on in pregnancy to prevent the yellow body breaking down and maintain the supply of progesterone. I love this – the idea that your baby is chemically manipulating you right from the start.

They quickly come up with the idea of some kind of receptors. They’ve picked up on my much repeated assertion that if you can do jigsaws, you can do Biology. But somehow they’ve got to colour code the receptor. And they’ve got to arrange things so that there’s a control line as well as the positive/negative line. Someone finally hits on antibodies, and I scaffold some more, telling them that specific antibodies can be manufactured in sheep, and that antibodies can be tagged at the end of the constant region with the colour of their choice. Much amusement when someone imagines centrifuging a sheep (rather than the sheep’s plasma).

They keep going. They hit on the principle of capillary action. Perhaps the antibodies could move along a fabric or something? But then they need to be stopped. But only if they’re bound to HCG. Er, this is getting complicated. But they sketch it out, and I provide a bit more help, and they’re there. Pretty much. So when we finally draw out the diagram and sketch a positive/negative test, and answer some interpretive questions, they already know and understand it. pregnancy tests

It was a fabulous example of co-operative learning – it wasn’t a particularly bright group, but they trusted my implicit assertion that, yes, you can do this, and they worked together, every student making suggestions and thinking aloud. None of them could have done it on their own. As a group, they did.

They were thrilled at their own cleverness, and fascinated by the cleverness of the testing kit. And to add to my own happiness at a lesson that had worked so well, SLT had popped in to observe it as part of one of their Learning Walks.

Back to the PSAs! Have a good week.