Kabib Plateau Deer
Tell the students that in the last century, there were wolf packs in northern Arizona. Have a student come up to the U.S. map and locate Arizona. Tell the students that in the forests and meadows of northern Arizona wolves once hunted deer. Put a wolf cut-out on the board. Below it put three deer cut-outs. Tell them that the deer found food in the forest, nibbling moss, leaves and twigs. Put six tree cut-outs below the deer cut-outs. Try to arrange the cut-outs to form a pyramid shape. Point out that producers (the trees) fed the consumers (the deer) which fed other consumers (the wolves) making a food chain. Tell the students that people who lived in northern Arizona decided that wolves were a nuisance. They didn't like predators killing the deer they wanted to shoot as game. They thought the wolves threatened their cows and sheep. So they began hunting and shooting the wolves. The human hunters shot or poisoned every wolf in northern Arizona. Remove the wolf cut-out. Ask: With the wolves gone, what do you think happened to the number of deer? (Their numbers increased.) Tell the students that with no wolf predators, many more deer survived and the deer population grew and grew. Add four more deer cut-outs to the row on the board. Tell the students that population explosion is a way to describe the number of deer. Ask: What did the deer eat? (twigs and leaves from trees) Did the number of grown-up trees increase quickly? (no) Point out that trees grow slowly. The deer's food supply stayed the same, but the number of animals depending on it increased. Tell the students that the deer were so hungry that they began eating young trees that couldn't survive the nibbling. Those trees died. Before long, the forest had fewer trees. Remove some of the tree cut-outs. Ask: What do you think happened to the deer when their food supply dwindled? (They starved.) Tell the students that many of the deer died because there was not enough to eat. Remove all but two deer cut-outs.
Ask: What was the result of killing all the wolves? (At first there were more deer, but then there were fewer trees and fewer deer.) Tell the students that the people who killed all the wolves did not understand that the web of life connects animals and plants together. What happens to wolves affects what happens to deer, trees and any other plants and animals in their food web.