Ecology Review Answers
True or false
F
1. A predator is defined as an animal that eats only meat
F
2. The carbon cycle has been disrupted by the addition of fertilizers
T
3. The disruption of the carbon cycle is leading to global climate change
F
4. Sediment pollution occurs when children spill sand from their sand boxes
F
5. An exotic species is defined as an organism that looks especially fancy
F
6. Competition occurs only between individuals of the same family
T
7. An example of a population is all the frogs in the river behind the school.
F
8. Nitrogen in the atmosphere is captured by plants and converted into a useable
form
T
9. Carrying capacity is defined as the maximum number of individuals that an
ecosystem can sustain
F
10. When pollution in an aquatic system increases it has no effect on the
community of organisms in that ecosystem.
T
11. 10 % of the food energy in organisms at one trophic level is transferred to the
next trophic level.
12. Bioaccumulation is a process that decreases the amount of a substance in an
ecosystem.
F
Multiple Choice
1.
Biotic components include:
a.
b.
2.
c.
d.
nutrients.
water.
Some abiotic factors affect some organisms more than others. A mouse is least affected by
a.
b.
3.
soil.
bacteria.
light.
water.
c.
d.
oxygen.
nutrients
Plants are important to the biosphere because they
a.
convert solar energy into chemical energy. c.
take carbon dioxide out of the air.
b.
cycle water through leaves.
d.
make homes for other organisms.
4.
5.
Cellular respiration is a
a.
carbon sink.
b.
carbon source.
c.
d.
way to make methane.
way to convert food into usable energy.
Photosynthesis is a
a.
carbon sink.
b.
carbon source.
c.
d.
way to make food energy.
way to make methane.
6.
Which trophic level do decomposers take energy from?
a.
producers
c.
carnivores
b.
herbivores
d.
all of these
7.
A population reaches its carrying capacity
a.
when no more individuals can be
supported.
b.
when all food has been eaten.
8.
9.
10.
c.
every summer when young are produced.
d.
after it has been protected from people
The common earthworm is an exotic species introduced into North America. No native
earthworms lived in the Great Lakes area before the exotic earthworms arrived. The native
earthworm for western North America is the giant palouse worm that is now rare. In the 19th
century palouse worms grew to be 1m long. Now they are about 8 cm long. People who
study this worm would like it to be listed as an endangered species.
Which of these statements is true?
a.
Earthworms in our garden are endangered. c.
Farmers normally poison the familiar
earthworm as a pest.
b.
The Palouse worm is a better competitor.
d.
The common earthworm is an invasive
species
What trophic level is made up of herbivores?
a.
primary producers
c.
secondary consumers
b.
primary consumers
d.
tertiary consumer
The bacteria that break down nitrates and return the nitrogen gas to the atmosphere are
called:
a.
c.
nitrogen-fixing
nitrite-fixing
b.
nitrate-fixing
d.
denitrifying
Short Answer
1. Use the diagram shown below to answer the following.
a) Identify two abiotic factors and two biotic factors in the diagram. Explain your reasoning.
b) Describe the relationship between an abiotic factor and a biotic factor in this ecosystem.
c) How does the variety of biotic factors help the sustainability of the ecosystem?
a) Abiotic: oxygen, water, methane
Biotic: plants, birds, jellyfish, dolphins, seals
b) Some abiotic factors provide life sustaining components
to the ecosystem without which organisms would not survive
c) the greater the biodiversity (# of different species in the
ecosystem) the greater the stability of that ecosystem
because if an abiotic factor changes the
community is more resilient (not as affected)
2.
Which natural process reduces atmospheric carbon, photosynthesis or cellular respiration?
Photosynthesis
carbon dioxide + water  glucose + oxygen (takes CO2 out of the atmosphere)
Cellular respiration
glucose + oxygen  carbon dioxide + water
3. Below is a description of food relationships in a desert. Draw a food web to show the feeding
relationships.
In a desert the major producers are often the sagebush, prickly pear catcus and wildflowers. The squirrel
feeds on the sagebush and in turn is eaten the badger, snakes and raptors flying by. The cactus and
wildflowers are eaten by insects and deer. Lizards eat feed on the insects and in turn are eaten by
raptors, coyotes and badgers. The coyotes also feed on the deer.
Do on BOARD in classroom – make sure arrows point to the consumer
4. Name and describe two different types of organisms that are responsible for inputting nutrients
into nutrient deprived ecosystems.
Decomposers:
return nutrients held within other organisms to the soil
Nitrogen fixing bacteria in legume roots (plants like clover)
Plants convert carbon dioxide from the atmosphere into usable energy for consumers
5.
What are two ways that carrying capacity can be increased?
CC can be increased by increasing resources (food, water) or increasing habitat.