How are these two creatures helping each other (the bird gets insects for food, the impala gets a clean ear)? What is it called when two creatures help each other in this way (a "symbiotic relationship" or "symbiosis")?
Can you think of any other examples of this sort of relationship (insects, like bees, sucking nectar from flowers and then spreading their pollen; bacteria living in cows' intestines and helping them digest plants). Symbiosis, at its best, is mutual, so what is a parasite (the one-way version, a creature that lives off another, like mistletoe, a blood-sucking louse, or the cuckoo)?
Can you think of human symbiotic relationships (people who sell things you like and then become rich themselves; parents who get on well together and support one another)? Are there any bad versions (bribery, corruption, the thief's "fence")? Do you think most children are "symbiotic" (parents look after them, they give parents pleasure), or "parasites" (just sponge off their parents and give nothing back)?
A spaceship lands near the bird and impala. Write a conversation between you and a space creature, explaining what is happening.
Ted Wragg is professor of education at Exeter University