MAMMOTH TEETH IN THE EARTH SCIENCE CLASSROOM: DEVELOPING SKILLS IN MEASURING, GRAPHING, COLLECTING DATA, AND HYPOTHESIS-TESTING

Mammoth molars are large, visually engaging objects that capture the interest of middle school and high school earth science students. Here we introduce an open-ended lab activity that involves the use of a collection of mammoth molars, all of which were collected at a single paleontological site in Las Vegas Valley. The activity was designed at UNLV and is currently being tested in classrooms within the Clark County School District of Southern Nevada. Sets of plastic-resin casts of the teeth circulate among the teachers involved. A four-part, forty-minute DVD has been created which introduces each component of the activity.

Throughout a mammoth's lifetime, if it lived long enough it used a total of twenty-four teeth, six in each quadrant of its mouth. We know from studies of elephants (which are close relatives of mammoths) that as one tooth got worn down, it was pushed out and replaced by a larger tooth. Each of the six teeth that moved through each quadrant of the mouth was longer and wider than the one it replaced. Students can quickly learn to distinguish upper-jaw teeth from lower-jaw teeth, and right teeth from left teeth. By measuring the length and width of a particular tooth and plotting their measurements on a graph, students determine which of the six molars they have in front of them: M1, M2, M3, M4, M5, or M6. They then use another graph to determine the approximate age of the animal that died when their tooth was deposited in the fossil record. By sharing data with their classmates, students then construct an age profile histogram of the mammoth assemblage, and they use this age profile to test hypotheses about the extinction of mammoths at the end of the Pleistocene.

In addition to helping students learn about the Pleistocene fossil record of North America, this activity emphasizes skills in measuring, graphing, working in teams, collecting data, sharing data with other teams of scientists, and hypothesis-testing.