|
| Overview |
| Grade Level: 9-12 |
| Background Information:
In many parts of the country, native species have been driven out
of their habitats by human activities leading some species to become
endangered or even extinct. Today, several large animal species
are being reintroduced to their native ecosystems. These include
large predators such as gray wolves. Many people see the reintroduction
of predator species as a threat to their livelihood. People are
also afraid that large predators are a danger to other humans. Other
groups of people see native species, including large predators,
as part of the natural ecosystem and are working to reintroduce
them to their native habitats.
This lesson addresses the complexities of native species reintroduction.
Students will learn that the carrying capacity of an ecosystem depends
on a variety of limiting factors, of which, predators are just one.
In fact, the presence of predators can help control the growth of
prey species for a more balanced ecosystem.
Acknowledgements:
Thanks to Daniel H. Pletscher, Director Wildlife Biology Program,
School of Forestry, University of Montana and Christopher G. Guglielmo
, Division of Biological Sciences, University of Montana for their
help with the data and information included in the lab activity.
|
| Content Standards |
| Related National Standards
This lesson addresses the following National Content Standards
found at: http://books.nap.edu/html/nses
Content Standard C: As a result of their activities in grades
9-12, all students should develop understanding of
- Interdependence of organisms
- Organisms both cooperate and compete in ecosystems.
The interrelationships and interdependencies of these
organisms may generate ecosystems that are stable for
hundreds or thousands of years.
- Living organisms have the capacity to produce populations
of infinite size, but environments and resources are
finite. This fundamental tension has profound effects
on the interactions between organisms.
- Matter, Energy, and Organization in Living Systems
- The distribution and abundance of organisms and populations
in ecosystems are limited by the availability of matter
and energy and the ability of the ecosystem to recycle
materials.
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|
| Extension Web Sites
from PBS: |
|
Scientific
American Frontiers - the New Zoos: Return to the wild
Activities about designing zoo habitats and maintaining genetic
diversity in captive breeding programs for reintroduction.
Newton's
Apple - Bison Roundup
This site contains activities related to the return of the bison
from near extinction. It includes an activity about how scientists
count populations of animals.
Nova
- Night Creatures of the Kalahari
Go to the "Life in a Bottle" activity for a classroom lab that tests
the predator-prey relationship.
Nova
- Relocation Challenge
This site outlines the challenges of relocating wolves to their
native habitat.
The
Living Edens - The Wolf and the Moose
This is a role-playing activity that shows students the dynamics
of the predator-prey relationship.
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| Activity 1: Extinction and
Endangered Species: What Can You Do? |
| Time Allotted:
20 minutes
Materials:
No special materials necessary.
| Objectives: |
- Students will understand that human activities are leading
to the extinction of record numbers of species.
- Students will determine methods that humans can use to
slow the current rate of extinction.
- Students will predict the result of reintroducing a native
predator species to a local ecosystem.
|
 Watch
the AFG Video Segment:
 |
Protecting
the San Pedro River Watershed
In
an attempt to protect the entire ecosystem of the river, parts
of the San Pedro River Valley have been designated as a 'national
conservation area.' |
|
Note: Watch from he beginning until you hear 'and we should
be the ones that monitor that.'
|
| Brainstorming Questions:
Do these questions as a group, or have students work in groups
of three to write ideas on a paper before discussion.
|
- What human activities are leading to the extinction of
such record numbers of species?
- What are some actions that humans might take to slow the
current rate of extinction?
|
Watch the AFG Video Segment:
|
Return
of the Wolf
The
United States government enlisted the assistance of the Nez
Perce Indians to help reestablish wolves in Idaho. |
|
Note: Clip starts at 'we're part of the animal world, we're
not separated from it' Watch through to the end.
|
Related Sites:
A congressional report discussing the effects of this wolf reintroduction
can be found at http://www.cnie.org/nle/biodv-13.html
Writing Activity:
Ask students to write in their journals about the following question:
According to the video, the reintroduction of the Grey Wolf in Idaho
is causing problems in ranching communities. What affect do you
think it might have on native populations such as deer?
|
| Activity 2: Oh Deer, Here Come
the Wolves |
| Time Allotted:
45-minute class period
Materials:
Graph Paper
Student Instructions Handout
| Objectives: |
- Students will plot graphs of animal populations to understand
the concepts of carrying capacity, population explosion,
limiting factors, and biotic potential.
- Students will analyze data to correlate the population
dynamics between a predator and a prey species.
- Students will challenge their assumptions regarding the
impact of reintroducing a predator species.
|
Classroom
Activity
Have students follow the directions and complete the activities
outlined in the Student Instructions Handout
.
- Have students read over the scenarios and make a prediction
about which case would be better for a deer to experience.
You may want to do this part as a class wide discussion
so that students can explain their reasoning and hear what
the other students are thinking.
- Students may work with a partner to graph the data. They
will eventually produce two line graphs (for assessment
see graphs samples).
- After students complete question # 4, tell them that the
wolves were reintroduced to the population illustrated in
graph A between the 1980 and 1981 population counts.
- Once this is complete, have students analyze their predictions
and answer the questions on the student sheet. This will
allow students to evaluate their own assumptions regarding
the effects that the wolf population will have on the deer
population.
|
Note: The data in this lab is based on several real cases
in which reindeer were introduced to Islands in the Pribilof Islands.
For more information on the population studies of reindeer go to
http://www.dieoff.org/page80.html. The population of deer affected
by wolf reintroduction is fictitious with some data based on information
provided by Daniel Pletcher.
Extension Activity:
Have students examine graphs of human population growth. Discuss
what might happen to the global human population based on what the
students saw from their graph.
Assessment:
Answer key for student activity hypothesis and analysis questions.
|
Describe and Hypothesize
- In graph A, population drops for a number of years and
then begins to oscillate. In graph B, the population grows
exponentially and then crashes.
- Both show a significant drop in population. However, in
graph A, the drop doesn't decimate the deer population and
the population is able to become stable (an S-shaped curve).
In graph B, population skyrockets and then plunges (a J-curve
showing exponential growth).
- Answers may vary.
- Answers may vary.
Analysis
- Other factors may have limited the deer population growth.
In this case it was food.
- Food, water, shelter, climate, space, predators, reproduction
rate
- In graph A, the reintroduction of wolves caused the carrying
capacity to lower. In graph B, the carrying capacity was
temporarily exceeded.
- Very bad shape. You can tell your students that the deer
had eaten and destroyed all the food by trampling it. The
primary source of food was lichens which are very slow to
grow. Once they were depleted, there was no renewed source
of food.
- Answers may vary
- Yes, depending on the types of limiting factors (e.g.,
predators, climate etc.)
- Yes
- Not necessarily. Populations can grow out of control and
limiting factors help keep populations within boundaries.
Perhaps the presence of a predator would have helped keep
the deer population on the island down so that they wouldn't
have caused so much damage to the surrounding ecosystem.
- Answers may vary. According to Daniel Pletcher, one of
the complications in a real system was the severity of the
winters. In very cold winters, the wolves killed more deer
than in milder winters.
|
|
| Activity 3: The
Reintroduction of Bighorn Sheep |
| Time Allotted:
15-20 minutes
Materials:
No special materials necessary
| Objectives: |
- Students will learn how non-native species can lead to
the extinction of natives.
- Students will consider the value of native species reintroduction.
- Using knowledge about population growth, students will
predict the future of the Bighorn Sheep population.
|
Watch
the AFG Video Segment:
|
Reestablishing
Bighorn Sheep in Oregon
Oregon
wildlife officials take extensive measures to capture and reintroduce
once-plentiful bighorn sheep into Oregon mountains. |
| Discussion Questions for Video Segments: |
- How did the actions of humans lead to the local extinction
of the big horn sheep?
- Why do you think people will go to this much effort to
reintroduce native species? Do you think it's worth it?
- Why do you think the relocation effort has been so successful
in this area? What would happen if the sheep were released
in Florida?
- Originally 20 Bighorn Sheep were reintroduced to this
area. Now there are nearly 2000. These numbers are similar
to the numbers of reintroduced deer before the population
crashed. Do you think the bighorn sheep are due for a population
crash soon? Why or why not?
- Do you think that the reintroduction of Bighorn Sheep
will have an impact on local domestic sheep populations?
Why or why not?
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