Ecosystems and Species Diversity
Teacher’s Guide
By Susan B. Parsons (NSF GK-12 Idaho State/Marsh Valley High)
Lesson Overview:
Subject Area:
1. Basic introduction to ecosystem structure and functioning.
General Biology
2. Measure plant biodiversity in the field and using diversity indices.
3. Come up with a definition for ecosystems.
Topic: Ecosystems
and Biodiversity
National Science Education Standards Addressed:
Audience:
9th/10th Grade
Suggested time:
1 hour
Resources:
Textbook
PowerPoint lecture Ecosystems and Species Diversity
Materials:

Notebook,
pencils, field
site
Biodiversity calculator, can be found online @:
http://alyoung.com/Site/Educational_Tools/Robert_Louder/Biodiversity_Calculator/
Learning Objectives:
1. General introduction to ecosystems, including definitions, components, and how they change
through time.
2. Observe different levels of biodiversity in the field.
3. Gain experience making observation in the field and taking good field notes.
4. Use statistics to qualitatively and quantitatively assess a biological phenomenon/condition.
5. Have students come up with their own definitions of an ecosystem.
Background:
Ecosystems are composed of biotic (animals and plants) and abiotic (geology, climate) factors
that interact with each other in a given unit of space. The boundaries of an ecosystem depend on the
particular group of interacting biotic and abiotic factors of interest, and could include a single rotting log
on a forest floor, or the entire forest. Ecosystems change through time by the process of succession,
which describes how different species of plants compete and replace one another. Biodiversity is a
measure of how many species there are in an ecosystem, and how abundant each of those species is.
Biodiversity can be used as an indication of ecosystem health, with more diverse ecosystems being more
likely to recover from disturbances, such a drought or disease.
This exercise is designed to give students some very basic information about ecosystems, and
then bring them out into the field to make observations on the biodiversity of an ecosystem. This is
meant to be an introduction that takes a single class period. When I did this with my students, we took
15 minutes to go over the PowerPoint lecture, and then brought students outside to a nearby pond
(within walking distance), and had students count the number of plant species, as well as how many of
each species there were in a given plot/area. In the last 20 minute of class, students were asked to
compile there data with their classmates, calculate Simpson’s and Shannon’s indices in order to get an
idea of how diverse this pond ecosystem was, and come up with their own definitions of an ecosystem
for homework.
Assessment Strategy:
Each student is asked to take field notes describing the species and abundance of each species of plant
in their plot of land, write down the diversity indices the class calculated together describing the
compiled data, and then submit a paragraph describing, in their own words, what an ecosystem is.
Assessments can be made based off:
1. Quality of field notes
2. Inclusion of calculated biodiversity indices, and what they mean
3. Paragraph defining ecosystems assigned as homework.
Teaching Tips:
1. Break students into groups before sending them to their plots of land for census. These plots
can be general areas, or be measured quadrats with specific dimensions-depending on how
qualitative or quantitative you would like this exercise to be.
2. It isn’t necessary that the students know the exact names of each species of plant, as long as
they can clearly describe and count it (ie. small, broad leafed herb with tiny white flowers-17
rosettes). There must be corroboration among groups, however, on how to describe certain
species so that data can be compiled in the end. Alternately, field guides could be used to
improve accuracy. Ground cover, such as grass or moss, can be described as percent cover, and
then multiplied by the appropriate power of ten.
3. Have students compile data on board.
4. Calculate biodiversity using an online “calculator” found at:
http://alyoung.com/Site/Educational_Tools/Robert_Louder/Biodiversity_Calculator/
(very nice to have a smart classroom overhead projector to do this) as a class, and have students
write down results.
5. Go over how to interpret the results of Simpson’s and Shannon’s Diversity indices described in
PowerPoint lecture.
References:
Johnson, G.B. and P.H. Raven. 2001. Biology: Principles and Explorations. Holt, Rinehart, and Winston.
Austin, TX.