ECOLOGY UNIT REVIEW
Topics:
1. Levels of biological organization
2. Feeding Relationships
3. Biotic relationships – Predation, symbiosis (mutualism, commensalism, parasitism) and
competition
4. Energy movements through the ecosystem – Trophic levels, pyramid of energy and calculating
transfer of energy through the pyramid.
5. Bioaccumulation and biomagnification
6. Nutrient cycles:

Carbon and nitrogen cycles – various processes involved (how the nutrient moves
between living and nonliving parts of an ecosystem)

The reactions for photosynthesis and cellular respiration

Role of decomposers in recycling nutrients.

Human impacts on nutrient cycles
7. Human impacts on sustainability of biodiversity
8. Carrying capacity and limiting factors
9. Species at risk
Part A: Write the word(s) needed to complete each of the following sentences.
1. The solid part of the Earth’s surface is called the _____________________________.
2. Oxygen is required by almost all organisms for the process ______________________________
and is a by-product of ______________________________.
3. The _______________________ refers to all water on the Earth in solid, liquid and gas states.
4. An ecosystem is __________________ if it can continue to function over very long periods of time.
5. A(n) __________________ describes a community of living things and their surrounding physical
environment.
6. Because of its warm, moist climate, a tropical biome is home to many different plants and animals,
and so it is said to have high _____________________________.
7. When non-native species are able to outcompete native species, they may become
____________.
8. Some pesticides and other environmental toxins build up or _______________________ in the
__________ tissue of living organisms.
9.
A(n) ____________________________ is a single species growing in one area.
10. The population that an ecosystem can support continuously is called its __________________.
Part B: Matching the terms on the left with descriptors or appropriate example on the right
Term
Letter
Descriptor or appropriate example
Match the terms on the left with appropriate example on the right
Mutualism
A. Burrowing owls nest in abandoned ground squirrel tunnels
Parasitism
B. Robins feed heavily on earthworms
Commensalism
C. Fruit eating bats feed on figs and spread their seeds
Competition
D. The winter tick lives on moose and feeds on its blood
Predation
E. Overcrowding can lead to food shortages and starvation
Match the terms on the left with appropriate example on the right
Species
A. Herd of elephants
Population
B. Tropical rain forest
Community
C. A raccoon
Ecosystem
D. Deer, grass, trees, wolves, rabbits of Algonquin park
Biome
E. Puslinch Lake
Match the terms on the left with appropriate definitions on the right
Extinct
A. A species that may become threatened or endangered
Extirpated
B. A species facing imminent extinction or extirpation
Endangered
C. A species that no longer exists
Threatened
D. A species that no longer lives in a particular region
Special concern
E. A species likely to become endangered if factors do not change.
Part C: Short answers
1. Describe two abiotic factors and two biotic factors that could affect a population of squirrels.
2. Snapping turtles eat frogs, frogs eat grasshoppers, and grasshoppers eat grass.
(a) Construct a food chain using the above organisms.
(b) What happens to these organisms when they die?
(c) What is the source of energy for the producers?
(d) If the grass was sprayed with a pesticide, in which organism would you find the highest
concentration of pesticide?
3. List four impacts that humans have on biodiversity and sustainability.
4. In what ways might individuals of the same species compete with each other if they are
(a) Carnivores
(b) Producers.
5. Give an example of an invasive species and describe how it has affected an ecosystem.
6. You drive past a pond that is covered in a layer of green algae. Why might this have
happened?
7. Use a T chart to compare photosynthesis and cellular respiration using the following criteria:
(a) What raw materials are needed?
(b) What are the products?
(c) Which occurs in plants?
(d) Which occurs in animals?
(e) Is light needed?
(f) Is energy released?
(g) Is energy needed?
(h) Is chlorophyll needed?
8. Describe how nitrogen from the atmosphere is converted to nitrates that plants can use.
9. Differentiate between the processes nitrogen fixation and denitrification.
10. Examine the two simplified food webs and answer the questions below.
Prior to European settlement throughout
southern Ontario
Cougar
White-tailed deer
Grasses
Wolf
Elk
Shrubs
Moose
Aquatic plants
Southern Ontario after 200 years after
European settlement
White-tailed deer
Beaver
Grasses
Shrubs
Elk
Moose
Aquatic plants
Beaver
Aspen trees
Aspen trees
(a) List differences in the two food webs. Give a possible explanation for your observation.
(b) What impacts do you think these changes had on the remaining species?
(c) Is it surprising that some regions of Ontario are experiencing overpopulation problems with
white-tailed deer and beaver? Explain.
(d) Lyme disease is spread by wood ticks that feed on white-tailed deer. Predict how these
changes might influence the spread of Lyme disease.
11. Examine the graph below.
The Population of Mink from 1730
to 1743
Number of Mink
1500
1000
500
0
1725
1730
1735
Year
1740
1745
(a) During which years is this
population of minks
growing the fastest?
(b) What is the carrying
capacity of the population?
(c) What factors cause the
population to level off
rather than continue to
increase?
(d) What may have
contributed to the sudden
increase in minks?