Lesson 3 - Dichotomous Keys

Question 1

Dichotomous Key

Answer 1

• A device used to identify an unknown organism.
• It means, “divided into two parts“ (Greek).
• A dichotomous key consists of a series of two-part statements that describe characteristics of organisms.
• At each step of a dichotomous key, the user is presented with two choices.
• As the user chooses a particular characteristic of an organism, they are led to a new branch of the key. Eventually, the user will be led to the name of the organism that they are trying to identify.

How to…
* Use constant characteristics rather than variable ones.
* Use measurements rather than terms like “large” and “small”.
* Use characteristics that are generally available to the user of the key rather than seasonal characteristics or those seen only in the field.
* Make the choice a positive one - something “is” instead of “is not”.