Teacher Site Map
7th Grade Core
USOE Science Home Page
USOE

A taxonomic key can also be called a dichotomous key. A taxonomic key is designed to look at the similarities and differences between objects using a series of paired statements. The paired statements describe contrasting characteristics (it is best to use observable physical characteristics). You choose one statement of the pair that is true of the object you are trying to identify. The statement you choose may ask you to go on to another pair of statements, or it may give you the name of the object.

For example, here is a taxonomic key to some common forms of money you may have handy. Gather some money (penny, nickel, dime, quarter, $1 bill, $2 bill). Choose one denomination of money and try to follow the key to identify what you have. Although you already know the names of the denominations of money you are looking at, practice using the taxonomic key.

 

Money Taxonomic Key

  1. Is it made of metal?
  Yes ............................................... Go to 2
  No ............................................... Go to 5
  1. Is it a silver type color?
  Yes ............................................... Go to 3
  No ............................................... Penny
  1. Is the outer edge smooth?
  Yes ............................................... Nickel
  No ............................................... Go to 4
  1. Is there an eagle on the back?
  Yes ............................................... Quarter
  No ............................................... Dime
  1. Do the corners have a number 1 in them?
  Yes ............................................... $1 Bill
  No ............................................... $2 Bill

Now you are to use a taxonomic key to identify plants of Utah. This key is designed to help you find differences between common evergreen trees in the state of Utah (not every evergreen tree in the state is included). Have a competition with some of your friends. See who is able to use the key to identify the most trees!

Analysis:

  1. Which trees were most similar and the most difficult to identify?
  2. Which trees were you able to identify most easily?
  3. How many trees did you have which were not on this list?
    • Borrow a tree identification guide from your teacher or the library and see if you can identify the names of the trees which were not on the list.

Review science safety rules here.

Get the plug-ins: Get Adobe Acrobat Reader , and Get Quicktime Player. (The Quicktime plug-in is needed to play sounds and movies correctly.)

Want to share photos of you or your friends doing this activity? Send it in an e-mail with the following information:

  1. The title of the activity
  2. The URL (Internet address)
  3. Your name.

Remember that no pictures can be used that show student faces or student names on it. 

Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE 7th grade science core.


Updated October 24, 2008 by: Glen Westbroek

Science Home Page | Curriculum Home Page | 7th Science Core Home Page | USOE Home Page


Copyright Utah State Office of Education.