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Regulating
Population Growth
A WebQuest for 9th-12th
Grade (Biology/Ecology)
Designed by
Ryan D. Wayt
[email protected]
Introduction
| Task | Process | Conclusion | Evaluation
| Credits
Introduction
When refering to populations,
a limiting factor is a factor that causes population growth to
decrease. Some limiting factors inlcude competition, predation,
parasitism and disease, human disturbances, drought and other climate
extremes. There are two types of limiting factors.
A density-dependent limiting factor is a limiting factor that depends
on a population's size. These factors become evident only when
the population desity reaches a certain level- they usually only have a
strong impact on large populations. Competition, predation,
parasitism and disease are all examples of density-dependent limiting
factors.
A density-independent liming factor is a limiting factor that affects
all populations regardless of their population size. Unusual
weather, natural disasters, seasonal cycles and human activities are
all examples of density-independent
limiting factors.
In this activity, you will work with the same group that you worked
with to complete a presentation on one of Colorado's ecosystems.
This time, your group will be asked to write a 2-3 page paper that
describes how limiting factors regulate population growth in the same
ecosystem that you previously reported on. Throughout this activity you
are to consider the question:
How do limiting factors regulate population growth within a specific
ecosystem?
The Task
At the end of this
activity, your group will have completed a 2-3 page pager describing how limiting factors regulate
population growth in the same ecosystem that you previously reported on. In your paper, you should be sure to distinguish
between density-dependent limiting factors and density-independent
limiting factos. Your
paper should also include a table that summarizes the findings of your
research, as described in the paper.
The
Process
1)
Your
group will be responsible for researching how limiting factors regulate
population growth in the same ecosystem that you previously
reported on. The following
are the 8 different ecosystems of Colorado:
- Grasslands
- Sage Shrublands
- Montane Shrublands
- Pinon-Juniper
Woodlands
- Montane Forest
- Subalpine Forest
- Alpine Tundra
- Riparian
2)
Obtain the Colorado
Division of Wildlife packet entitled "WILD Colorado: Crossroads of
Biodiversity" that you used for your last project, or download the
packet yourself at:
- WILD Colorado: Crossroads of Biodiversity - This is where you will find a lot of
your
information, or clues as to how you might begin researching the
information somewhere else. For example, if the Burrowing Owl is
a species found in your ecosystem then you might go to Google and type
in "Burrowing Owl populations", or "threats to Burrowing Owls". If you can't seem to find
anything for one species, move on to another species found
in your ecosystem.
3)
Your group will work collaboratively
to write a paper describing how limiting factors regulate population
growth in your assigned ecosystem. It would be a good idea to
split the
topic
into different
sections and assign each group member a section to research and report
on. Your group's paper should meet the following requirements:
- A typed 2-3 page
paper that follows MLA style formatting .
- A title page that
inludes a title, the name of the class, the group member's names listed
in alphabetical order, and the date that the paper was completed.
- Detailed examples of
at
least four different types of limiting factors that affect the
populations
of different species found in your
ecosystem. At least one limiting factor must be a
density-dependent limiting factor, and at least one limiting factor must be a
density-independent limiting factor.
4)
When
your paper is complete, hand it in to your instructor.
Conclusion
At the
end of this project, you should be able to describe specific examples
of how both density-dependent and density-independent limiting factors
affect a specific ecosystem of Colorado.
Evaluation
Individuals
in the group will receive a grade according to their quality and
quantity of research, communication with the group, and accountability
to the group by using the Group
Work Rubric.
The entire group will recieve a separate grade based on the quality of
the final paper. A Regulating
Population Growth Rubric is available for the students and
teacher to use.
Credits
Opening
image retrieved from: http://www.waterencyclopedia.com/images/wsci_01_img0136.jpg
Some text modified from:
Miller,
K. R., & Levine, J. (2002). Prentice Hall Biology. Pearson
Education, Inc., Upper Saddle River, New Jersey.
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