Name:_______________________
Period_____________
CPO Lab 3B
Crazy Creatures Dichotomous Key
A dichotomous key is made from a series of steps, each consisting of two statements. The
statements describe the characteristics of an organism or group of organisms. Usually, a
dichotomous key starts with broad characteristics that become more specific as more
choices are made. As you read each step, you choose one of the two statements based on
the organism’s characteristics. Eventually, the statements lead you to the name of the organism
or group to which it belongs. In this investigation you will create a dichotomous key to identify
imaginary creatures.
Setting Up
1. Examine the creature cards. Compare and contrast the major features of the creatures.
2. Make up a name for each creature – be imaginative!
3. Make a list in the table of the characteristics that may be helpful when you classify the creatures
into different groups. Some characteristics to consider include: numbers of arms/legs, types of
body parts and body covering.
Creature Number
1
Creature Name
Characteristics
2
3
4
5
6
7
8
9
10
Stop and Think
1. What types of features are contained in Table?
2. Can you think of one feature that would divide all of the creatures into 2 groups?
Developing a key to the creatures
1. Obtain a large dichotomous chart template.
2. Examine the creatures. Think of a “Yes/No” question that, upon answering, separates the creatures into two
groups. Write the question on your chart.
3. If the answer to question 1 is YES, write the number of the corresponding creatures below the YES box. If the
answer is NO, write the numbers of the creatures below the NO box. For the YES group, make a new YES/NO
question that would sort the creatures in that pile into two more groups. NEVER recombine the creature cards
once you have sorted them into groups.
4. Repeat the process you used in step 3 for the first NO group and continue the process until all of the creatures
have been sorted into piles of single creatures.
Making a dichotomous key
Use your key charts to create a dichotomous key to identify the creatures. Write your entire key below:
1a
1b
2a
2b
3a
3b
4a
4b
5a
5b
6a
6b
7a
7b
8a
8b
9a
9b
After you have created a complete dichotomous key, choose ONE of your creature cards and EXCHANGE
it with another group. See if they can correctly identify the creature and you will identify theirs. Fill in
the box below after the exchange:
I exchanged creatures/keys with Team #__________________
Circle one :
(worked!! I was able to identify the creature)
(oops, it didn’t work)