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Dichotomous Keys. Dichotomous Key. A dichotomous key is a tool that allows the user to identify organisms or things, such as trees, wildflowers, mammals , reptiles , rocks, and fish.
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Dichotomous Key • A dichotomous key is a tool that allows the userto identify organisms or things, such as trees, wildflowers, mammals, reptiles, rocks, and fish. • It does this by allowing the user to choose from pairs of descriptions about the organism’s visible characteristics. • "Dichotomous" means "divided into two parts”. Therefore, dichotomous keys always give two choices in each step.
Rules When Using a DK • Always start at the top. • Only look for 1 organism at a time. • Read each choice and decide yes or no, then move on. • Follow each step until you are narrowed down to one thing/organism.
Example: Type of Plant Diagrams can also be ways to show a Dichotomous Key
Rules When Making a DK • Use permanent characteristics that are visible on the thing/organism itself. Don’t use behavioral characteristics. • Be specific~ do not say things like big or small • Make choices positive~ something is or has not something is not or does not have • If possible start each choice in the pair with the same word. • When a series of steps are finished name the thing/organism.
