The Key to Classifying

We know that organisms are classified using the Linneaen taxonomic system, and they are named using binomial nomenclature. However, what do we do when we encounter an unknown organism? How can we name an organism found in the wild?

A dichotomous key is a tool used to identify organisms in a systematic way. It can be used to identify organisms parting from a certain taxonomic level. These keys are organized in such a way that the user has to make certain choices according to certain characteristics of the organism. Each step of the dichotomous key offers two choices (thus the name; dichotomous means: divided in two parts) until it points to a specific organism that has all the characteristics previously chosen.

Dichotomous keys are useful for identifying organisms in the field, or even in the lab when there is no other information available about the organism. Keys make come in diagram or in written form.

Here are two examples:

MLA: McGraw Hill. "Taxonomic Classification and Phylogenetic Trees." McGraw Hill Higher Education. The McGraw-Hill Companies, 2001. Web. 12 Aug 2010. .