Activity 9.1: Tropics versus the Poles
I. Draw the food webs
On separate sheets of paper, draw typical food webs for a coral reef ecosystem and
an Antarctic ice-edge ecosystem. Include the following:
 the organisms discussed in the episode
 other organisms, based on your web search
 highlight flows of energy from the sun through the food web to heat
 highlight the recycling of carbon and nitrogen through the food web
 indicate primary producers, primary consumers, higher trophic levels and
decomposers
 a list of the physical and chemical factors that may affect these food webs
Use your textbook, the video episode and the web sites below to identify the major
organisms and their links. As well, use these web sites to better understand and
depict the major pathways of energy and matter
Recommended web sites:
The Ecology of Coral Reefs
http://www.soc.soton.ac.uk/GDD/hydro/atmu/ecology/menu.html
Coral Reef Ecosystem
http://www.reefrelief.org/coralreef/
Coral Reef Ecology
http://www.fcsc.usgs.gov/Coral_Reef_Ecology/coral_reef_ecology.html
Coral Reefs Resource Guide
http://www.aquarium.usm.edu/coralreef/
Antarctica – Wildlife
http://www.antarctica.ac.uk/About_Antarctica/Wildlife/index.html
Classroom Antarctica
http://classroomantarctica.aad.gov.au/
Arctic Ocean Ecosystems
http://envirosphere.ca/pdf/arctic.pdf
Arctic Sea Ice: Channels of Life
http://oceanexplorer.noaa.gov/explorations/02arctic/background/sea_ice/sea_ice.ht
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The Ecosystem and Food Web of the Antarctic Peninsula
http://www.literacynet.org/polar/pop/html/project-ecosystem.html
II. Compare and contrast
Now that you have a picture of the food webs of these ecosystems, compare and
contrast their similarities and differences. Use the table below to guide your thinking.
Then complete the critical thinking questions below.
Characteristic
Average water temperature?
Coral Reef Ecosystem
Polar Ecosystem
Average day length?
Abundance of dissolved nutrients?
Effects of seasonal changes in physical
and chemical factors on food web?
Who are the primary producers?
Who are the major consumers?
Who are the top predators?
Who are the decomposers and
detritivores?
How does the ecosystem export or
retain organic matter?
How does man affect this ecosystem?
III. Critical Thinking Questions
1. In what ways are the flows of energy and cycling of matter similar in coral reef
and polar ecosystems? In what ways are they different?
2. How do fluctuations in the external environment—the physical and chemical
factors—govern the flow of energy and cycling of matter in these ecosystems?
3. Coral reefs are often called steady-state systems while ice-edge ecosystems are
pulsed or non-equilibrium systems. How do these characteristics, i.e. steady-state or
non-equilibrium, allow or not allow these ecosystems to adapt to changes induced by
humans, such as global warming? (This is a tough question but take your best shot.
There’s no right answer here but this question does test your understanding of these
ecosystems and the effects of human activities.)