The Natural Selection of Stick-Worms

This lesson teaches students that traits are usually favored by natural selection only when they result in more reproductively successful offspring. Students go out onto the school lawn and play the role of birds, picking up toothpick stick worms which have been previously scattered in equal numbers of green-stained and unstained. Birds are chased away before the worm population drops too low. Back in the classroom, the number of green and non-green worms are compared individually and for the whole class. Discussion relates the experience to the elements of natural selection. As presented here, it does not lend itself to demonstrating the effects of selection over multiple generations. Educational levels: High school, Middle school