dichotomous key

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Last updated

July 23, 2026

Quick Summary

A dichotomous key is a tool used in biology to identify organisms. It works by presenting a series of choices between two alternative characteristics. By following these paired options, you can narrow down the possibilities until you identify the specific organism you are studying. This method is effective for classifying and understanding the diversity of life.1

In contrast, a polychotomous key offers a choice between several alternative characters, rather than just two.2

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taxonomy
The objectives of biological classification
…are set out as a dichotomous key with opposing pairs of characters. The butterflies of a region, for example, might first be separated into those with a lot of white on the wings and those with very little; then each group could be subdivided on the basis of other characters.…
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…are set out as a dichotomous key with opposing pairs of characters. The butterflies of a region, for example, might first be separated into those with a lot of white on the wings and those with very little; then each group could be subdivided on the basis of other characters.…
Read More