Ecology Review
Part A: Multiple Choice: Circle the best answer.
1.
a)
b)
c)
d)
e)
2.
a)
b)
c)
d)
e)
3.
a)
b)
c)
d)
e)
4.
a)
b)
c)
d)
e)
5.
a)
b)
c)
d)
e)
Carbon in the atmosphere is mostly in the form
of:
Methane
Carbon dioxide
Carbon monoxide
Water
Ammonia
6.
a)
b)
c)
d)
e)
A similarity between combustion and
respiration:
They both produce heat
They both produce carbon dioxide
They both produce greenhouse gases
They both consume oxygen
All of the above.
Carbon is cycled from the atmosphere to plant
matter mostly through:
Burning
Cellular Respiration
Transpiration
Photosynthesis
Decomposition
7.
a)
b)
c)
d)
Greenhouse gases:
Carbon dioxide, water, methane
Water, methane, ammonia
Methane, carbon dioxide, ammonia
Methane, oxygen, carbon dioxide
8.
Carbon is cycled from dead organisms back
into the atmosphere mostly through:
Combustion
Cellular Respiration
Transpiration
Photosynthesis
Decomposition
a)
b)
c)
d)
e)
These organisms turn dead organic matter into
basic abiotic nutrients:
Scavengers
Predators
Decomposers
Parasites
Omnivores
Carbon is cycled from live organisms back into
the atmosphere mostly through:
Combustion
Cellular Respiration
Transpiration
Photosynthesis
Decomposition
a)
b)
c)
d)
e)
A relationship between species living in the
same area is called:
Symbiosis
Mutualism
Diversity
Photosynthesis
Tragedy of the commons
10.
a)
b)
c)
d)
e)
The term “autotroph” literally means:
“self-feeder”
“automatic level”
“car washer”
“level mover”
“plant eater”
11.
a)
b)
c)
d)
e)
Another word for “heterotroph”:
Consumer
Producer
Decomposer
Parasite
Herbivore
The main difference between combustion and
cellular respiration is:
Combustion occurs at a faster rate than cellular
respiration
Combustion produces heat and cellular
respiration does not
Combustion produces greenhouse gases and
cellular respiration does not
Combustion pollutes the air
None of the above.
9.
12.
a)
b)
c)
d)
e)
This material is rich in nitrogen:
Methane
Carbon dioxide
Water
The lithosphere
Manure
13.
a)
b)
c)
d)
e)
The chemical symbol for ammonia is:
CH4
CO2
H2O
NH4
C6H12O6
14. This process requires carbon dioxide and water
and produces oxygen
a) Photosynthesis
b) Cellular respiration
c) Combustion
d) Farting
e) Peeing
15.
a)
b)
c)
d)
e)
At the bottom of a food chain, web or pyramid:
Producers
Primary consumers
Secondary Consumers
Top predators
Parasites
16.
a)
b)
c)
d)
e)
Three examples of biomes:
Scavengers, predators, decomposers
Grasslands, aquatic, desert
Pond, river, lake
Lithosphere, atmosphere, hydrosphere
None of the above
17.
a)
b)
c)
d)
e)
Another word for non-native:
Invasive
Exotic
Indigenous
Parasitic
Autotrophic
18.
a)
b)
c)
d)
e)
Not a decomposer:
worm
vulture
bacteria
fungus
millipede
19. A _________________ consumes primarily animals
that are recently killed by another species:
a) decomposer
b) scavenger
c) parasite
d) herbivore
e) consumer
20. Cows add to the greenhouse effect most
strongly by:
a) Producing manure
b) Eating grass
c) Farting
d) Breathing oxygen
e) Respiration
21. Certain birds clean the ears of water buffalo by
eating fleas that nest in the ear. This is an
example of:
a) Predation
b) Commensalism
c) Mutualism
d) Competition
e) Bilingualism
22.
a)
b)
c)
d)
e)
Put in order from smallest grouping to largest:
Ecosystem, biome, community, population
Biome, ecosystem, community, population
Community, population, ecosystem, biome
Population, community, ecosystem, biome
Community, ecosystem, population, biome
23. This organism belongs to more than one
trophic level:
a) Dandelion
b) Rabbit
c) Cow
d) Human
e) None of the above
24. A robin eats insects and worms and builds
nests in trees using bits of fallen branches and
loose grass. It can be preyed on by cats. This
describes the robin’s :
a) Niche
b) Habitat
c) Community
d) Population
e) Gender
25. In a dense jungle, taller trees get the most
sunlight. This is an example of:
a) Mutualism
b) Commensalism
c) Predation
d) Parasitism
e) Competition
28.
a)
b)
c)
d)
e)
Which of the following is TRUE?
All invading species are introduced
All introduced species are invasive
All introduced species are native
All native species are exotic
None of the above.
26. Examples of abiotic limiting factors:
a) Food availability, water availability, climate
b) sunlight availability, water availability,
temperature
c) number of predators, oxygen level, climate
d) living space, food availability, availability of
mates
e) none of the above
29. A pond can support a dozen or so turtles before
it begins to get too crowded. Any more than
this and the food supply will start to become
scarce. This is an example of:
a) Carrying capacity
b) The greenhouse effect
c) An engineered ecosystem
d) The tragedy of the commons
e) Biodiversity
27. Which of the following is TRUE? Introduced
species are:
a) all brought on purpose from another land
b) all invasive in their new land
c) all non-native
d) never able to adapt to the new environment
e) always top of the food chain.
30. In a food web:
a) Producers are at the bottom
b) Arrows indicate the direction of feeding (i.e.
from food to consumer)
c) Some organisms have multiple arrows
d) Energy is lost from one trophic level to another
e) All of the above
Long Answer Questions:
1. Explain the difference between a law, a theory and a hypothesis.
Law: A statement that generalizes observations on a certain subject. Examples: “what
goes up must come down.” “Cars must stop at red lights.”
Theory: An accepted explanation for a certain phenomenon. Theories are tested and can
change to reflect any new information. Scientific theories are generally well tested and
have not been modified in a long time. Examples: theory of gravity, the theory of
evolution, the Big Bang theory.
Hypothesis: An educated guess of what will happen during an experiment. Unlike a
theory, a hypothesis has not been tested yet, but will be through experiment.
2. What is the origin of all energy on Earth? The sun is the source of most of the energy on
Earth. The Earth itself has some energy in the form of heat in its core (geothermal
energy) and rotational energy (because it is spinning). But 99.9% of all life gets its
energy directly (plants) and indirectly(consumers) from the sun.
3. What is a biome? A biome is a region with a distinct climate and ecology. The aquatic
biome and the desert biome, for example. In one, you have lots of water, aquatic animals
and plants, a little sunlight and cool temperatures. In the other you have little water,
plants and animals adapted to the hot and dry conditions, and hot temperatures. Other
examples of biomes are forest (tropical, deciduous, boreal), grasslands (savannah) etc.
4. Explain the greenhouse effect. This is the effect when certain gases in the atmosphere
reflect heat back down onto the Earth. Rays from the sun heat up the Earth’s surface.
Most of these rays reflect off the Earth and head out into space. Gases like CO 2 , H2O
and CH4 reflect some of this heat back down and do not let it escape. When this
happens, the Earth warms up, like a greenhouse (a greenhouse is a small house made of
clear plastic that traps the sun’s heat. This can be used to plant crops in the winter).
The trapping of heat in the atmosphere is called the Greenhouse Effect.
5. Explain why decomposers are so important in the carbon and nitrogen cycle. Without
decomposers, the carbon and nitrogen cycle wouldn’t be much of a cycle. Plants get
carbon out of the atmosphere by photosynthesis. They get nitrogen directly from the soil
and from certain bacteria (nitrogen-fixing bacteria) that take it out of the atmosphere
and put it in a form useable by plants. Consumers get carbon and nitrogen by eating
plants. The consumers store some of it and excrete some carbon (manure) and nitrogen
(urine) back to the soil. The rest is released when they die. Decomposers turn this biotic
material back into CO2 and N2 gases where it returns into the atmosphere. Without
decomposers, the atmosphere would run out of CO2 and N2, plants would die without
CO2 and the Earth would be overflowing with dead corpses, urine and manure.
6. What is the primary difference between a community and an ecosystem? A community is
a group of all organisms living in an area. The ecosystem includes the community, but
also includes the non-living (abiotic) elements, such as the water, land and air.
7. Draw the carbon cycle.
Just Google “carbon cycle” and look at the images. Here are some examples:
http://commons.wikimedia.org/wiki/File:Carbon-cycle-full.jpg
http://www.frankswebspace.org.uk/ScienceAndMaths/physics/physicsGCSE/carbonCycle.htm
The key processes are:
 Photosynthesis
 Combustion
 Respiration
 Decomposition
 Diffusion in and out of water
The middle three processes (combustion, respiration, decomposition) put CO2 into the
atmosphere, increasing the Greenhouse effect. Only the other two (photosynthesis and
diffusion from water) take CO2 out of the air.
The stores of carbon are:
 The atmosphere
 In all living things
 In sediments at the bottom of the ocean (mostly from shells)
 In fossil fuels under ground
 In water and ice (bubbles of CO2)
Until recently, the first two stores traded carbon back and forth in a stable cycle. Now
the burning of fossil fuels and the melting of the ice cap is releasing much more carbon
dioxide into the air than we are able to cycle back.
8. Name 3 carbon sinks.
A sink is a store. See answer above for 5 possible answers.
9. Explain why North Americans demand for beef is a direct cause of global warming.
 Cows produce methane, a greenhouse gas. More methane in the atmosphere means
the sun’ s rays are being trapped and reflected back on the Earth, causing the
temperature of the Earth to increase.
 Cows produce CO2 and H2O when they breathe. This is not such a big problem as
the methane, since they don’t produce as much and it does not have as much an effect
on the greenhouse effect.
 Cows are produced on large farms which need to have trees removed. Clear-cutting
a forest will mean fewer trees for photosynthesis. This means less CO2 is removed

from the atmosphere. CO2 is another greenhouse gas, so this produces more global
warming.
Cows are often farmed in countries far away and then shipped to our grocery. The
shipping process burns fossil fuels (fuel for trucks and boats), which in turn
produces more CO2.
10. Give an example of a limiting factor that becomes more of a factor with increasing
population density. Availability of food, habitat. Living space, disease, predators.
11. Give an example of a limiting factor that becomes more important as population
decreases. Availability of mates (for sexual reproduction, for safety, for division of
labour).
12. Give an example of a limiting factor that is not affected by population density. Climate,
temperature, earthquakes, forest fires.
13. If the rabbit population in a certain area were suddenly rid of predators (wolves, fox,
coyote, hawks etc.) what would happen in the short and long term? Short term – rabbit
population would go up. Long term – disease, lack of food, cramped living space – rabbit
population might stabilize or go down. If there is lots of space and food can be found,
population would thrive.
14. Write the equation for photosynthesis as a :
a) Word equation carbon dioxide and water + energy (sunlight)  oxygen and glucose
b) Chemical equation CO2 + H2O + Energy  O2 + C6H12O6
c) Balanced chemical equation. 6CO2 + 6H2O + Energy  6O2 + C6H12O6
15. Repeat the previous question for cellular respiration.
Same, but in reverse:
d) Word equation oxygen and glucose  carbon dioxide and water + energy
e) Chemical equation O2 + C6H12O6  CO2 + H2O + Energy
f) Balanced chemical equation. 6O2 + C6H12O6  6CO2 + 6H2O + Energy
16. Explain the greenhouse effect and global warming.
See question #4
17. Why are the carbon cycle and nitrogen cycle important for the survival of our planet?
See question #5. If carbon and nitrogen was not recycled, we would run out. When we
die, the carbon and nitrogen in our bodies is returned to the atmosphere, so that it can be
used again by plants and eventually consumed by other animals.
18. Explain the tragedy of the commons as it applies to a specific environment or ecosystem.
The tragedy of the commons is what happens when no one is in charge of a common
property. As a specific example, we all breathe air, but no one owns the air we breathe.
As a result, we pollute the air in many ways (combustion in cars, factories and homes,
cows produce methane, noise pollution in cities etc.). We do this even though we know
that it is bad for us! This has negative health effects, but no one is in charge, so it takes a
lot of work to get something done about it.
19. Explain why biodiversity is important for an ecosystem to be healthy.
Biodiversity is having many different species in an ecosystem. Diseases often target one
species. If a disease eliminates or weakens one species in a food web, then other species
in that food web will also be affected. If the food available is scarce, then the result can
wipe out an entire part of an ecosystem. If the ecosystem is diverse, then most species
will be able to find an alternative food source, and will not be so deeply affected.
In general, each species will be affected differently by limiting factors, other than disease.
For example, if the winter was long one year, that might wipe out a certain kind of grass
in an area. If there are many kinds of grass in that area, some will survive and take the
place of the grass that did not regenerate in the spring. If there is only one kind of grass
in that area, it might take years for the area to regenerate, wiping out many primary and
secondary consumers along with it.
20. Explain how bioengineered ecosystems can upset the local ecosystem.
Bioengineered (like a farm) ecosystems are designed to have little diversity on purpose.
They grow certain crops (like corn) and certain livestock (like sheep or cattle). The
problem is, they must be artificially watered (not relying on rain), diverting water from
lakes and rivers. Because they are on farms that have few trees, the water does not stay
in the soil, but it runs off back into the rivers. The crops are given nutrients to help them
survive (like fertilizer for plants and vitamins and hormones for animals). They are given
pesticides to protect them from predators and pests. All of these chemicals end up
draining into the rivers when it rains. The fertilizer causes plant life in ponds, rivers and
lakes to grow out of control, which chokes out and kills the fish. The pesticides and
hormones and vitamins end up also getting into our lakes and into our drinking water,
making our water unsafe to drink. When we eat the plants and animals, we ingest these
chemicals and end up potentially getting sick. Finally, when the chemicals end up being
ingested by other organisms, they get bio-amplified up the food chain, so that by the time
we consume them, they have become dangerous to us.