CLASSIFICATION IN THE CLASSROOM: A MIDDLE SCHOOL EXPLORATION OF TAXONOMY, FOSSILS, AND EVOLUTION

Middle school students often struggle with foundational concepts such as common ancestry and classification. Here I present a series of lessons designed to give students an experiential understanding of these ideas.

The objective of Lesson 1 is to explore the process of classification while modeling scientific investigation, collaboration, and presentation of research. Each group of students attempts to classify a mystery creature (the okapi) solely by comparing a picture of part of its anatomy to the corresponding features in several ungulate clades. Each group has a different okapi feature and is not aware they are all studying the same animal. After each group presents its hypothesis, the instructor reveals that all mystery photos were from one species, initiating an intergroup dialogue about the mystery animal’s clade. Regardless of whether a consensus is reached, the instructor emphasizes the importance of hypothesis testing and collaboration in research.

The objectives of Lesson 2 are to reveal how additional data can support or weaken a hypothesis and show the importance of osteological data to taxonomy. Each student group matches a picture of the mystery creature’s skull to the ungulate’s skull it most closely resembles. After each group presents its hypothesis, the groups debate any disparate hypotheses. Finally, the instructor reveals the okapi’s identity as a member of Giraffidae.

The objective of Lesson 3 is to demonstrate how fossils allow scientists to test evolutionary hypotheses. The instructor asks if the okapi and giraffe are only classified together due to common traits or if they share ancestry as well, encouraging a discussion of the extent to which animals change over time. After receiving pictures of giraffe and okapi skeletons, each student group describes traits a transitional form between okapis and giraffes might possess, completing their hypothesis with a drawing. After asking the class to discuss ways these hypotheses might be tested, the instructor reveals pictures of extinct giraffid skeletons with intermediate neck lengths. Each group then completes a writing assignment comparing their hypothesis to the Giraffidae fossil record and explaining the importance of fossil data.