SNC 1D
ECOLOGY UNIT REVIEW
Your Test Date is _____________________________
Sustainability: A sustainable ecosystem - Tragedy of the Commons, abiotic vs. biotic factors,
abiotic characteristics of an ecosystem (water, oxygen, light, nutrients, soil), natural vs artificial
ecosystems
Energy and Feeding relationships: ecology, ecosystem, ecotone, herbivore, carnivore,
omnivore, detritus, decomposers, food chain relationships: Trophic levels: producers, primary,
secondary, tertiary consumers, decomposers, food chains, food webs, autotroph, heterotroph…
Types of pyramids: energy, biomass, numbers; energy through the ecosystem (loss)
Bioaccumulation (contamination) and bioamplification, DDT, etc. and affects on organisms
Biogeochemical cycles: generalized cycling of matter in the environment.
Water cycle: evaporation, condensation, precipitation, transpiration
Carbon cycle: organic vs inorganic, Photosynthesis and Cellular Respiration equations,
complementary processes, human impacts on carbon cycle, climate change, reservoirs of
carbon, combustion
Nitrogen Cycle: nitrogen-fixing bacteria, denitrification, useable forms of nitrogen (nitrates);
Human impacts on Nitrogen cycle – effects on ecosystems: agriculture (depletion), fertilizers,
algal bloom, eutrophication, acid rain
Populations: population vs community; niche vs habitat, roles in ecosystem (ex. Hawk vs. owl)
competitive exclusion, biotic interactions (mutualism/symbiosis, predation/ parasitism,
competition, commensalism), native species vs exotic species and invasive species (ex. Zebra
mussels, killer bees, ash borer beetle)
Population dynamics: population growth equation (births + immigration) – (deaths +
emigration), open vs closed populations, limiting factors on carrying capacity: abiotic vs biotic,
materials and energy, food chains, competition (intraspecific – among the same species, and
interspecific – between species), density-dependent (stress, aggression, neglect of offspring,
disease) vs density-independent factors (forest fires, floods, droughts).
Interpreting population graphs (predator-prey ex. moose-wolf, linear vs. exponential growth
patterns, carrying capacity).
Change and succession: climax communities, primary and secondary succession – evolution
of dominant species, importance of burning.
Biodiversity: importance of biodiversity, impact of reduced biodiversity; dominant species,
keystone species (sea otter, prairie dog), indicator species (frog), ecosystem engineers
(beavers); Ecosystem Services: nature’s economy, link to sustainability; (forests, insects,
migratory birds, ecological connectivity)…pollination, decomposition
Measuring biodiversity: canopy fogging, quadrant sampling, transect sampling, netting
Threats to Biodiversity (& solutions): overexploitation (fishing, hunting), extinction (captive
breeding), habitat loss deforestation (reforestation), draining wetlands (remediation), invasive
species (biocontrol, chemicals), disrupting connectivity of ecosystems.
Practice Questions:
True/False
Indicate whether each statement is true or false. Correct each false statement by the changing the bold part.
T / F 1. Organic substances come from living things.
T / F 2. A hawk and an owl occupy the same ecological niche.
T / F 3. A carnivore is a primary consumer.
T / F 4. Nitrogen fixation replenishes the atmospheric nitrogen supply.
T / F 5. The maximum number of organisms that an ecosystem can support without harming itself is called the
carrying capacity.
Multiple Choice
Circle the letter of the best answer for each of the following questions.
6. With an overabundance of nitrates in our waters:
a) algae flourish and fish die from oxygen depletion
b) all aquatic animals benefit
c) freshwater fish live longer because of increased micronutrient supply
d) all fish benefit from an abundance of algae
e) productivity of the ecosystem declines
7. Interconnecting food chains are called:
a) food pyramids
b) food webs
c) food biomass
8. The entire biotic environment depends on
a) omnivores
b) consumers
c) herbivores
d) producers
d) food nutrient cycles
e) a food biome
e) 2 of the above
9. Dead organic matter in soil is best termed:
a) detritus
b) humus
c) carrion
d) excrement
e) abiotic
Short Answer
10. Define the following: niche, habitat.
11. Distinguish between ecosystem, biome and biosphere
12. Explain why pesticides are used and how their use can lead to bioamplification.
13. Why is a decline in the number of frogs important?
14. Explain what happens to the amount of energy when food is transferred to different trophic levels?
15. Why is the greatest number of species found in an ecotone?
16. Identify a density-dependent factor and a density-independent factor that affects population size.
17. Explain the term competitive exclusion. How can more than one organism at the same trophic level co-exist in
an ecosystem?
18. Compare and contrast native species, exotic species and invasive species. Give examples of each. Explain the
impact that an invasive species could have on the ecosystem.
19. Explain why it would be wrong to underestimate the mighty Beaver.
Diagram
20. Draw a food web using organisms of your choice from the following list of organisms belonging to a
pond ecosystem. Draw one pyramid of energy and one pyramid of numbers from this food web.
Duck (herbivore)
Small Fish (omnivore)
Submerged weeds
Algae
Frog
Insects (herbivore)
Small snake
Large Fish (carnivore)
Insects (carnivore)
Tadpole
Emergent grass
21. Use as many terms as possible to describe the organisms in your food web (producer, heterotroph, trophic
levels, etc)
23. Sketch a graph that illustrates the relationship between rabbit and fox populations over time (predator-prey
relationship. Sketch a graph of rabbit population alone over time. Indicate the carrying capacity. What factors
would affect the carrying capacity of the rabbit population? Classify these factors as density-dependent and
density independent.
24. Sketch graphs to illustrate the difference between linear growth and exponential growth. Explain the difference
in words.
Communication Questions:
25. Discuss one way in which humans are impacting the nitrogen cycle – give as much detail as possible. Use a
flow chart or diagram if appropriate
26. How is human activity affecting the carbon cycle?
27. Discuss ways that humans are threatening biodiversity. Why is it difficult to prevent this? What can be done
to improve the situation?
28. Discuss Sustainability. Give examples of how humans are not being sustainable. Give examples of how
humans are attempting to create sustainability.
Think, think, think… predict the questions that you may see…
Review your quizzes, homework questions and worksheets…