Dichotomous Keys
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Transcript Dichotomous Keys
Introduction to Agriculture, Food, and Natural
Resources
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Introduction to Agriculture, Food, and Natural
Resources
Dichotomous Keys
Unit 4 – Lesson 4.2 The Order of
Classification
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What is a Dichotomous Key?
• A method for determining the identity of
something by going through a series of
choices that leads the user to the correct
name of the item.
• Dichotomous means "divided in two parts“
• Somewhat like playing the game “20
Questions”
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Using Dichotomous Keys
Start by observing the item to be identified.
List the most general traits of that item.
At the beginning of the key, select the
choice that best describes your item.
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Using Dichotomous Keys
Each step will involve making a choice
between two characteristics.
Each statement should lead you to the
next step to narrow the selection further.
Each step will either identify the item or
direct you where to go next in the key.
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Example
1. If the object is used for writing, go to 2
1. If the object is used for organizing go to 3
2. The object makes a gray mark…pencil
2. The object makes a blue mark…pen
3. The object is metal...paper clip
3. The object is elastic…rubber band
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References
Detka, J. (2009). Designing and using a
dichotomous key. Retrieved from
http://watershed.csumb.edu/ron/roncor/cor/did.ht
m
Enchanted Learning. (2010). Make a dichotomous
key. Retrieved from
http://www.enchantedlearning.com/subjects/plan
ts/activity/key.shtml
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