Use evidence to support arguments that changing any physical or biological component of an ecosystem may result in shifts in the populations of species in the ecosystem.

1. Ecosystems
Why might a change in an ecosystem
affect populations of species within
that ecosystem?

2. Have you ever seen a
caterpillar munching on a
leaf, or a bird drinking
water from a puddle?
Have you noticed that the
leaves of some trees only
change color as the
weather gets cooler?
All of these observations, and others like them, are
examples of the many different types of interactions
that occur within ecosystems.

3. An ecosystem includes
all the living organisms
existing together in a
particular area. These
organisms, like plants
and animals, depend on
each other to survive.
They also interact with
the nonliving elements
of the area, such as
water, soil, rocks, and
climate.
Click here for more information about ecosystems.

4. Click here to Click here to play
watch a short a quick
video vocabulary game
Click here to
read a short
news article

5. The balance of an ecosystem is very delicate!
Changes to the ecosystem, such as the
introduction of a new species or drought, can
be disastrous to all organisms within the
ecosystem.

7. Images courtesy of Jack and June Anthony of jjanthony.com
These three pictures show the growth
of kudzu in an area over time. Predict
how the invasion of kudzu will affect
other plants and animals in this area.
Click here for more information about kudzu.

8. Click here for a Click here to play
short video a quick game
about other
invasive species
Click here to
read a news
article

9. Part 1: Print these instructions before clicking on
the link below. Use the virtual ecology lab to
simulate the disruption of an ecosystem by an
invasive plant species.
Part 2: After completing part 1, start the
simulation over and try to create a sustainable
ecosystem in which all of your species survive. If
one species has a population of zero at the end of
the simulation, start over and try a different
scenario. Which scenario creates the most stable
ecosystem?
Go to Virtual Ecology Lab

10. Virtual Ecology Lab Instructions
Part A) Simulating a stable ecosystem:
a) Click on All Off.
b) Click on Plant C (the third plant in the row) and select it from the menu.
c) Click on Herbivore A (the first herbivore in the row) and set it to eat Plant C.
d) Click on Omnivore A (the first omnivore in the row) and set it to eat Herbivore A.
e) Click RUN and observe that the plant, herbivore, and omnivore populations
eventually reach equilibrium (their population numbers stop changing).
Part B) Simulating the disruption of an ecosystem by an invasive plant species:
a) Click on Reset. (Plant C, Herbivore A, and Omnivore A should still be connected in a
food chain.)
b) Click on Plant A (the first plant in the row) and select it from the menu. This plant
represents an invasive species, a strong competitor to Plant C.
c) Click RUN. What happens to the populations of each species in the ecosystem? Give
an explanation for the results. (hint: think of a chain reaction or domino effect)
PART A PART B

11. Ecosystem
A community of living and nonliving things that
function together.
Examples:
– aquatic ecosystems
– desert ecosystems
– forest ecosystems

12. Species
A group of individual organisms that can
interbreed and produce fertile offspring.
Examples:
– humans
– cats
– wolves

13. Invasive species
Non-native organisms that are harmful to the
ecosystem they invade.
Examples:
– Kudzu vine to the southeastern U.S.
– Caribbean tree frog to Hawaii

14. Drought
A period of dry weather caused by a lack of
rain.

15. 1. Define
– Ecosystem
– Species
2. Explain how the invasion of kudzu affects
other plants and animals within the
ecosystem.
3. Why might a change in an ecosystem affect
populations of species within that
ecosystem?

16. Credits
• The Habitable Planet – Ecology Lab
• How Stuff Works
• Kudzu Covered Houses
• neoK12
• NOVA beta – Invasive Species Matching Game
• Geography 4 Kids
• USDA National Invasive Species Information Center
• Unless otherwise noted, all photos are from the
internet and were labeled free to use, share, or modify,
even commercially.

17. Kudzu, a vine native to Asia, was introduced to the
United States in 1876. Eventually, it was used all
over the South as a way to control soil erosion.
Unfortunately, kudzu became a major problem.
The climate of the southeastern United States is
perfect for kudzu. With no natural predators in
the area, it can grow up to a foot per day (~30
cm)! This invasive species grows over anything it
touches, including trees, telephone poles, even
houses!