Ecology: Forest Food Webs
Big Idea:
Everything in nature is
connected.
You can’t change one
part of an ecosystem
without it having some
effect – large or small –
on every other part.
The COE (Collection of Evidence) consists of at least 6 and at most 8
student tasks, all done on line.
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Tasks show what you know and can do in relationship to state
standards. Each task has 10-12 questions on different topics.
All tasks accessed from the inclusion bank in the online Education
Data System (EDS) account.
A minimum of two tasks must be chosen as on-demand tasks – no
changing answers after first time. The rest are extended-time tasks
– you may go back and change answers later.
All tasks done by student alone. No help from others, no cheating.
Main Biology Topics:
1. Ecology: study of how living things interact with their
environments.
2. Cell Processes: how all life processes happen at the
cellular level.
3. Evolution/Genetics: how life on Earth has diversified
and changed over time.
4. Inquiry and Application: How science is used to solve
real problems in the real world beyond the classroom.
1.
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Suppose there was a decrease in the chipmunk population of the forest ecosystem
shown below. Describe an effect this would have on another population of
animals shown in the food web. In your description, be sure to
- Identify a population from the food web diagram.
- Describe an effect of decreased numbers of chipmunks on the identified
population.
Fewer coyotes because fewer chipmunks to eat.
More green plants because fewer chipmunks eating them.
More deer because fewer coyotes eating them.
2. What do you think would happen to the population of green plants eaten by mice if
all the owls died or disappeared? Explain your answer.
Population of green plants would decrease because more mice eating
them, because no owls eating the mice.
X
3. Unintended consequences are bad things that happen because of something we
did, even though we didn’t expect or want those things to happen.
Invasive species are animals or plants from elsewhere that tend to outcompete and
kill off native species of animals or plants.
Suppose people who kept snakes from outside Washington state as pets released
them into the forest here because they didn’t want to take care of them anymore.
Describe two unintended consequences that could happen as a result.
• Less food for native snakes
because new snakes
competing.
• Fewer native snakes
because they fight with
new snakes or get eaten
by them.
• Could bring in diseases
that could hurt or kill the
native snakes.
http://www.usnews.com/news/artic
les/2014/07/21/invasive-pythonsthreaten-florida-everglades
“As with many invasive species, lionfish are
in the wild because some were released by
aquarium owners in the early 1980s,
marine biologists say. The first Florida
sighting came in 1985 in Dania Beach, near
Fort Lauderdale. It wasn’t long before
lionfish were spotted in the reefs of the
Bahamas and then the rest of the
Caribbean during the 2000s. Their range
now extends from North Carolina to
Pensacola in the Gulf of Mexico and all
through the Caribbean.”
http://tbo.com/news/politics/invasive-andpredatory-lionfish-now-live-in-tampa-bay20141019/?utm_source=NCSnewsletters&utm
_medium=email&utm_campaign=AM+News+
Mail
Worst invasive species of the Pacific NW?
Himalayan blackberry
4. Nitrogen, a chemical element in our atmosphere, is needed by plants and animals
to build cells and tissues. Using the Nitrogen Cycle diagram shown below, explain
how nitrogen from the air gets into the cow’s body and how it goes back into the
surrounding ecosystem.
• Nitrogen from air changed by bacteria in soil into form that plants
take up through roots. Cow takes nitrogen in by eating plants.
• Through its poop, or when it dies and its body goes into the ground.
• Plants take it in from the ground through their roots.
5. The Department of Wildlife is considering the possibility of re-introducing grizzly
bears into the North Cascades forest ecosystem.
a. Describe two factors the Department of Wildlife officials should consider
about the forests of the North Cascades before releasing grizzly bears there.
• How will grizzly bears affect bears
already living there?
• How will grizzly bears affect
populations of animals and plants
they eat?
• Will they attack people?
5b. Ranchers in eastern Washington do NOT want the grizzly bears to be re-introduced because
the bears have been known to kill cattle. What scientific information would be needed to solve
the problem of how to protect the cattle without hurting the bears? How could that
information be gathered?
• Do grizzlies attack cattle? How
often? Look for records of
attacks or start keeping them.
• Are there fences that will keep
grizzlies out and cattle in? Try
different fences and see.
5c. Describe three possible solutions to the problem, including
any useful scientific concepts.
• Pay ranchers back for any cattle
proven to be killed by grizzlies.
• Put bear-proof fences around
cattle. Do electric fences work on
grizzlies?
• Use guardian animals like dogs to
bark when bears come. Will
grizzlies kill dogs?
• Put shock collars on bears. How
strong a shock can they take?
5d. A criterion is something that is used to measure the success of a proposed
solution to a problem. Aside from the number of cattle killed by grizzly bears,
what would be two other criteria biologists could use to evaluate possible
solutions to the above problem?
• Number of grizzlies surviving.
• Number of grizzlies having cubs.
• Health of other animals and
plants in the forest.
6. Sometimes biologists raise animals in captivity and release them into
the wild to increase populations. Describe one unintended consequence
of releasing orcas raised in captivity into the wild. In your response be
sure to:
- Describe one way orcas raised in captivity might differ from
orcas in the wild.
-Describe one impact of that difference on the ecosystem where
the orcas are released.
• Orcas in captivity used to being
fed by humans. Might have
harder time catching prey in the
wild.
• Orcas in captivity don’t interact
with other orcas as much.
Might not get along with own
kind in the wild.
7. Using the Predator-Prey Populations graph shown below, explain
how the population of prey affects the population of predators and
vice versa.
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When prey population goes up, predator population goes up
(more food for them).
When predator population goes up, prey population goes down
(more prey getting eaten).
http://www.bapp.org/puma-prey-lab
8. Positive feedback loops are when changing one thing causes a
continual increase or continual decrease in another thing. Negative
feedback loops are when increasing one thing causes an alternating
increase and decrease of the other thing. Is the predator-prey
relationship shown below a positive or negative feedback loop? Explain
your answer.
• Negative feedback.
• Populations going up and down instead of just up or just down.
Positive feedback loop:
• Both populations
only increase or only
decrease.
Negative feedback loop:
• Both populations increase and decrease.
Video: Positive & Negative Feedback Loops
http://ed.ted.com/lessons/feedback-loops-how-nature-gets-its-rhythms-anje-margrietneutel?utm_source=TED-Ed+Subscribers&utm_campaign=d8af586ac02013_09_219_19_2013&utm_medium=email&utm_term=0_1aaccced48-d8af586ac046516589
Questions…?
http://seattletimes.com/html/localnews/2025043554_seastarvirusxml.html?cmpid=2628
Get a computer and start logging on….
Plagiarism video
http://www.coe.k12.wa.us/Page/283
1. Take out this assignment to review.
2. Get a computer and start logging on……
9. Suppose a new species of owl was introduced to the forest ecosystem. Describe
two conditions in the forest ecosystem that might allow the new owl population to
increase rapidly.
Many animals for them to eat.
Few predators eating them.
10. Limiting factors = things that can limit the growth of animal or plant populations in
a particular area. Describe two ways an increase in one owl population could limit the
population of another owl species in the forest ecosystem.
Competition for food, nesting sites
11. What conditions do plant populations need to grow rapidly?
Water, light, soil.
Not a lot of animals eating them.
Not a lot of other plants competing for space.
12. Describe two ways an increase in one tree population could limit the growth of
another tree population in the forest ecosystem.
Competition for sunlight, soil, water.
Today’s task: DIY Plant Experiment, question 3
Helpful Hint: Include wording from the question in your
answer to make sure you’re answering the question!