Lesson 1: Models of the tree of life

How did the tree of life change through history?

Students learn about the nature of science as they examine how models of the tree of life have changed through history.  Students begin with an activity that introduces the classification systems of past scientists (including Carl Linnaeus, Ernst Haeckel, and Robert Whittaker) to recreate the historical timeline of different taxonomies using original scientific drawings and excerpts from scientists’ writings to support their model. For each different taxonomic model students examine, they address questions such as “What information did the scientist use to create this taxonomy?” and “What are some of the defining characteristics of each of the groups of organisms?” These progressions of scientific thought and models over time illustrate some key nature of science concepts: scientific knowledge is a result of human endeavors and has a history that includes the refinement of, and changes to ideas over time.

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