Create Your Own Dichotomous Key - Template And Instructions printable pdf download

Create Your Own Dichotomous Key

In this project, you will be creating a dichotomous key. Dichotomous keys are tools used

by scientists to identify unknown organisms.

1. Use the animals listed to create a dichotomous key.

2. Decide upon a way to divide the items into two groups. Think of identifying

characteristics such as shape, size, position, colour, texture, etc. One

characteristic must be defined and used to decide which items are placed in which

group. For example: a group of big cats could be divided into those with long tails

and those with short tails. The groups created must be opposites of each other.

3. Record what factor was used to make the division and note which members of the

original group belonged to each resulting group.

4. After two groups (A and B) have been created, divide the first group (A) into two

more groups based again on one criterion (C and D). For example, if group A were

the short tailed cats, group C might be short tailed cats with a plain colored coat.

Group D would then be short tailed cats with a patterned coat.

5. Do the same with Group B.

6. Continue to divide the groups until each item is by itself. Keep careful records of

the groups that were created and the dividing criteria.

7. Looking at your records and the divisions you made, create a dichotomous key that

would lead someone else to make the same distinctions you did. Begin your key by

recalling the first factor you used to divide into two groups. Again using the big cat

example: The first group was created depending on tail length. So, the first

question in the key should be: Does the cat have a short tail? If so, go to step 2.

The second question should be the other choice: Does the cat have a long tail? If

so, go to step ??? (You may need to wait until you have worked through several

steps of the key to assign the second destination.

8. When your key is complete, ask someone else to use it to classify and identify the

items. Does your key lead others to the same identifications you made? If not, you

may need to make some changes.

Create Your Own Dichotomous Key - Template And Instructions