Bio Lab ***ZEEK THE GEEK***

Exercise 1: Dichotomous Key Practice

A dichotomous key is an identification tool that starts with broad defining characteristics and splits into two options until an organism can be identified. In this exercise, you will identify organisms by their binomial nomenclature using a dichotomous key.

	Materials Dichotomous Key	Images of Organisms

Procedure

1. Start by observing organism i (Figure 2). Once you have taken notice of its physical characteristics, use the dichotomous key (Figure 3) to identify the organism.

2. Start at number 1 on the key and decide if the organism has feature “1a” or feature “1b”.

3. Which ever option you choose, follow the dotted line over to the next step that will state “Go to #”.

4. Go to that number and again decide between the two options.

5. Eventually you will wind up at a two name scientific name.

6. Once you have identified organism i, record your finding in Table 3.

7. Repeat Steps 1 - 6 for all of the organisms in the dichotomous key (Figure 3).

Table 3: Dichotomous Key Results
Organism	Binomial Name
i
ii
iii
iv
v
vi
vii
viii
ix
x
xi
xii
xiii

Figure 2: Organisms to be identified

Figure 3: Dichotomous key