Here’s how I introduced a new topic at the start of the autumn term for my bright and eager Year 10 classes this year.
It’s an interactive Powerpoint – no, wait! – nothing complicated, just a click and reveal quiz as they choose the blocks based on number or colour.
Simple question to start with, can they name any of the organisms?
In fact, why don’t you try it? See how many you get…
(brief pause while eager reader attempts quiz)
How did you get on? Here’s what Year 10s generally make of it.
They all get mosquito and vampire bat. Most of them will get flea and remember it as the Robert Hooke drawing from their introduction to microscopes in Year 7. The leech is sometimes identified as a slug, or a flatworm, but a little prompting gets them there. They often call the tick a spider – for valid reasons! – but usually get Tick, VG! (joke). Bed bugs is a lottery. I point them to the clues if they get stuck. Very few get beyond “bird” for the red-billed oxpecker, though students I have taught in previous years sometimes remember that this is my PhD species… and hardly any ever get the Masai warrior.
Next question – what do all these organisms have in common? The Masai and the oxpecker throw them, because they were thinking, “they all eat blood!” but this is new.
Yet they’re absolutely right. These are all organisms that subsist entirely or largely on a diet of blood.
I take time out to explain the Masai traditional lifestyle and how they use their cattle as a source of blood and milk. This year, I made up some stage blood and asked if anyone was brave enough to try the Masai diet. One brave girl tasted the blood/milk cocktail – and exclaimed, “that’s not blood!!!” (stage blood is syrup, corn starch and food colouring).
But, key question: what does this tell you about blood?
They instantly see that blood provides a perfect balanced diet. So it must contain what?
We discuss the types of carbohydrate, protein and lipids that appear in blood and their function. So many proteins! So many functions! This takes us neatly into the four main functions of blood as a whole (thanks to Bill Burnett for the following Powerpoint review)…
… and its overall structure….
…setting them up nicely for a look at their own blood in the next lesson.