Kindergarten Through Grade 4
Eventually only the flying birds will be left to reproduce, and their offspring will likely be flying birds too. There can be small variations in offspring, however, so maybe a few of these red birds will have green baby birds that can hide in the trees. The eagle will then eat the red birds but miss the green birds. Eventually, most birds will be green instead of red. Explain that in a similar way, new types of animal populationseven peoplecan develop over long periods of time. Show students pictures of some early hominids, including Australopithecus africanus, and ask what factors allowed these species to evolve into Homo sapiens. (Youll find appropriate pictures in the February 1997 and August 1998 issues of NATIONAL GEOGRAPHIC.)
Now compare humans to another type of mammal, such as a dog, cat, or horse. How are we similar to and different from this animal? What about a bird, reptile, or insect?
Give each student an index card bearing the name of an animal. (If time permits, students might draw their animals on the cards.) Have a variety of insects, birds, reptiles, nonprimate mammals, nonhuman primates, and human beings.
Gather the class around a large piece of poster board, a rug, or a table. Ask students to place their index cards in an order that represents the similarities between animals. The most primitive animals (insects) might be at the top, followed by species that have progressively more in common with people. Let students discuss where animals should be placed. Explain to the class that certain scientists have a similar job and must try to figure out the similarities and differences between all types of animals, including animals that have been extinct for a long time. In that case, they have to classify animals based on fossils, which is much more difficult.
About Early Humans
Art at left by John Gurche