Calculating Biodiversity
Name: __________________________
6th Grade PSI
Score: ______ / 9 points
-----------------------------------------------Activity/Lab Question:
How can the biodiversity of different ecosystems be assessed or calculated?
Background:
In order to understand the biodiversity of different areas, ecologists use a biodiversity
index. This is a simple calculation that they use to compare the biodiversity of different
areas.
To calculate a biodiversity index, ecologists first examine a small area of a particular
ecosystem. In each sample area, they count how many different species are present as
well as the number of each species.
The formula for biodiversity index is:
# of species present
Total # of individuals present
The closer this value is to 1, the higher the biodiversity.
For example, suppose that you are calculating the biodiversity of two different wildflower
meadows. The species data of each meadow is shown in the data tables below.
Meadow #1
Species
Abundance
Daisy
6
Butterfly weed
12
Black eyed Susan
7
Echinacea
15
Lupine
10
Meadow #2
Species
Abundance
Echinacea
10
Lupine
20
The biodiversity index of each meadow is calculated as follows:
Meadow 1:
# of species present
Total # of individuals present
=
5
50
=
0.1
Meadow 2:
# of species present
Total # of individuals present
=
2
30
=
0.07
A value closest to 1 indicates a higher biodiversity. This means that Meadow #1 has a
higher biodiversity than Meadow #2.
www.njctl.org
6th Grade PSI
Disturbance & Biodiversity
Before You Begin:
What is biodiversity?
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
A sample area of a forest ecosystem is assessed and found to have the following
composition: 30 loblolly pine trees, 10 live oak trees, 7 trumpet vine, 5 kudzu and 8
sassafras trees. What is the biodiversity index of this area? Show your calculation.
Purpose:
During this activity, you will learn how to calculate and compare the biodiversities of
different ecosystems.
Materials (per group):
 3 opaque containers filled with varying amounts of items
Procedure
1. Your teacher will walk around and give each group 3 containers. Each container
is labeled with a number and symbolizes a different ecosystem that you are
studying.
2. Start with container #1.
3. Carefully empty the container onto your work space.
4. Separate the items in your container into similar groups. Each group is a different
species in your ecosystem. Describe each species in the data table.
5. Count the number of individuals of each species that is present. Write this info in
the data table.
6. Put the items back into the container.
7. Repeat steps #3-6 with containers #2 and #3.
www.njctl.org
6th Grade PSI
Disturbance & Biodiversity
Data:
Container #1
Species Description Abundance
www.njctl.org
Container #2
Species Description
Abundance
6th Grade PSI
Container #3
Species Description Abundance
Disturbance & Biodiversity
Analysis
1. Based on your data, calculate the biodiversity index for the three containers.
Container #1
Container #2
Container #3
2. Which container has the highest biodiversity? Did this surprise you? If so, why?
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
________________________________________________________________
www.njctl.org
6th Grade PSI
Disturbance & Biodiversity