Photo Credit: HTO, via Wikimedia Commons
To explore various hypotheses concerning the extinction of the woolly mammoth.
In this lesson, students will explore a Web resource that presents various hypotheses about why the woolly mammoth became extinct, with a special focus on an infectious disease as the cause.
Woolly mammoths died out in a puzzling extinction event during the late Quaternary period. This extinction event also wiped out a large number of other large mammal species, including the sabre-toothed tiger and the Irish giant deer. In August of 1998, a research team from the American Museum of Natural History, led by Ross MacPhee, chairman of the Museum's Department of Mammalogy, traveled to the Arctic Circle. There, they conducted an 18-day expedition, hunting for mammoth bones and teeth in the soggy tundra. The website used in this lesson is a record of the expedition, and it also poses questions and possible answers about why the woolly mammoth died out. As students explore the resource, they are encouraged to think about how species might become extinct, as well as how researchers look for evidence to support their hypotheses and theories.
The notion that scientific knowledge is always subject to modification can be difficult for students to grasp. Although most students may believe that scientific knowledge changes, they typically think that changes occur mainly in facts or through the invention of improved technology. It is important to help students understand the development of scientific knowledge through the interaction of theory and observation. However, it is important not to overdo the "science always changes" theme, since the main body of scientific knowledge is very stable and grows by being corrected slowly and having its boundaries extended gradually. Scientists themselves accept the notion that scientific knowledge is always open to improvement and can never be declared absolutely certain. (Benchmarks for Science Literacy, p. 332.)
As directed on the Mammoth Extinction student esheet, begin by having students read the Introduction to What Killed the Mammoths.
Discuss MacPhee's idea that the only thing capable of causing the puzzling mammal extinctions of the late Quaternary period was a highly lethal infectious disease. The rest of the lesson will help to explain MacPhee's reasoning in greater detail. Use this discussion to focus students' ideas about what causes species extinctions and how scientists can find evidence for their hypotheses regarding these extinctions.
Using the esheet, have students explore the following parts of the website. Distribute the Mammoth Extinction student sheet so that students can answer questions as they explore the resources.
Use the Mammoth Extinction teacher sheet to assess students' understanding of the questions posed in this lesson.
Have students read What Dies Out and Why? The student esheet will direct students to write a brief essay discussing some of the reasons for extinctions posed in the article. The essay will ask them to apply the ideas and theories in the article to the extinction of the mammoths.
Students should be able to describe various hypotheses regarding the extinction of the woolly mammoth, especially the hyperdisease hypothesis. They should also be able to relate the example provided in this lesson to general ideas about how scientific knowledge is tested and developed and how researchers look for evidence to support their hypotheses and theories.
The Mammoth Site Museum in Hot Springs, SD, contains pictures, educational activities, research data, and other information that can help students learn more about the extinction of the mammoths.
The Discovery Channel has a series of videos on mammoths that may interest your students.