Dichotomous keys are used to identify and classify objects (i.e. people, animals, plants, bacteria, etc.) into specific categories based on their characteristics. It’s the most commonly used form of classification or type of identification key used in biology as it simplifies identifying unknown organisms. “Dichotomous” means divided into two parts, hence they present two choices based on key characteristics of the organism in each step. By correctly selecting the right choice at each stage, the user will be able to identify the name of the organism at the end.
Students can understand the use of a dichotomous key by creating their own using different types of foot-ware or U.S. coins. The activities provided will allow them to sort and group photos or dried specimens/shells into their proper classification categories.