TAXONOMIC (DICHOTOMOUS) KEYS

One method of classifying and identifying objects includes using a taxonomic key, sometimes called a dichotomous key. A taxonomic key looks 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 out of the pair that happens to be 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, etc.). 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 A. Metal....................................................go to 2

1 B. Paper....................................................go to 5

2 A. Brown (copper)........................................penny

2 B. Silver....................................................go to 3

3 A. Smooth edge...........................................nickel.

3 B. Ridges around the edge...............................go to 4

4 A. Torch on back..........................................dime

4 B. Eagle on back...........................................quarter

5 A. Number 1 in the corners...............................$1 bill

5 B. Number 2 in the corners...............................$2 bill

Now, try to make your own taxonomic key (similar to the money taxonomic key). Make your key separate out each of the 5 kingdoms. Remember to use pairs of contrasting statements.

Possible Answer (your answer may vary)

Sample Key To The 5 Kingdoms

1 A. only 1 cell................................................go to 2

1 B. More than 1 cell..........................................go to 3

2 A. No nucleus...............................................Monera

2 B. Has a nucleus............................................Protista

3 A. Autotrophic..............................................Plantae

3 B. Heterotrophic............................................go to 4

4 A. Mobile....................................................Animalia

4 B. Immobile.................................................Fungi.

Extension: Make a taxonomic key for something living (such as leaves or different kinds of pets).