Key

Key

A key is a taxonomical aid used to classify plants and animals — essentially a structured tool that lets someone work through a series of choices to arrive at the correct identification of an unknown organism.

Most keys used in taxonomy are dichotomous keys, built on pairs of contrasting characters. At each step, the user compares the specimen against a pair of opposing statements; whichever one matches is accepted, and the other is rejected, before moving on to the next pair of contrasting statements. Each individual statement within a key is called a lead. Because the process moves the user step by step toward a single correct identification, keys are described as being analytical in nature. …