The mysterious bony thing in this week's picture offers a wonderful opportunity for pupils to be detectives. Ask them what on earth it could be - a fossilised dinosaur dug up in the Arizona desert? A space creature from 'Star Trek'? Or is it real and alive? What clues do they pick up on?
The leafy sea dragon raises many points about life and the environment. How well is it adapted to its surroundings? It looks like the kelp that grows under the sea where it lives, so it is well disguised. It would be very conspicuous against sand or rock.
It sucks up food through its vacuum cleaner snout, like a pipefish. How and to what do creatures adapt? (Survival of the fittest, coping with temperature and climate, hunting and food gathering, land or sea, avoiding predators.) Can you think of other well-adapted species? (Polar bears, penguins, mice, worms, human beings.) What about the panda (can't breed easily, food problems), or the dodo (extinct since 1681, couldn't fly, too slow)?
How and why do creatures merge with their background to catch prey, and avoid predators. What about colour protection or changes (Arctic fox, chameleon), mimicry (black and yellow striped insects that do not sting, but look like bees and wasps). How does military camouflage work? (painted buildings, soldiers covered in twigs). Paint a picture of something camouflaged, or make a simple hide to watch birds.
* Ted Wragg is professor of education at Exeter University