Introduction to Dichotomous Keys Kit

Scientists use dichotomous, or taxonomic, keys to identify both living organisms and non-living specimens. Examples of this include a naturalist’s use of a field guide and a chemist’s use of the periodic table. All dichotomous keys are developed the same way—similarities and differences in characteristics and traits are observed and recorded. Similar to the way computers work (open/closed circuit), characteristics in dichotomous keys are typically given in pairs. The observer must make a choice as to which statement most accurately describes the specimen, since only one statement in each pair can be true. The statement chosen determines the next pair of opposing statements. Statement pairs become increasingly more specific until the specimen is identified. In this game-like activity, students focus on the physical attributes of an imaginary organism to narrow down its identification. The Introduction to Dichotomous Keys Kit provides materials for 30 students in grades 6 through 12.