Biology
Ecosystems Practice Quiz
Name_________________________________________________________________
Date________________________ Per_______
Directions: For each question, you MUST do all of the following-1) Highlight key words & annotate.
2) Rewrite the question in your own words.
3) Cross-out wrong choices & select the BEST answer.
4) Write one sentence explaining WHY the answer is correct. Why’s it correct?
1. Sea stars are fierce competitors with marine
organisms such as clams and mussels. An
ecologist studying an ocean ecosystem
performed an experiment in which the sea stars
were removed from the ecosystem. After the
removal of the sea stars,
A. the ecosystem became more diverse.
B. the size of the ecosystem was reduced.
C. food webs in the ecosystem became more
complex.
D. Clam and mussel populations flourished,
but the species who ate sea stars shrank.
3. In a balanced ecosystem with predators and
prey, if the number of prey decreases
A. the number of predators will decrease.
B. predators will begin eating other
predators
C. there will be no change in the ecosystem.
D. the number of prey will eventually
increase.
I know this answer is correct because…
I know this answer is correct because…
2. If the niches of two organisms overlap,
A. the organisms may have to compete
directly
B. the two organisms will always form a
symbiotic relationship.
C. both organisms will disappear from the
habitat.
D. Both organisms will thrive.
I know this answer is correct because…
4. Students show that pollutants may reduce the
numbers of plankton. How might this affect the
energy transfer between various tropic levels in
the Antartic ecosystem?
A. More energy will be available to the algae.
B. Less energy will flow to the next level at
each trophic level.
C. Less energy will flow from carnivorous
zooplankton to birds.
D. More energy will be available to the other
organisms in the food web.
I know this answer is correct because…
Page 21
5. The diagram below shows the
interdependence of organisms existing in a lake.
C. Decomposers take up a large amount of
space, keeping new plants from growing.
D. Decomposers convert dead organic
matter into nutrients that help new plants
grow faster.
I know this answer is correct because…
If a disease reduces the population of
planktivorous fish, what would be the MOST
LIKELY effect on the populations in the lake?
A. Algae would increase while piscivorous
fish and zooplankton would decrease.
B. Algae would decrease while piscivorous
fish and zooplankton would increase.
C. Algae and piscivorous fish would increase
while zooplankton would decrease.
D. Algae and piscivorous fish would
decrease while zooplankton would
increase.
I know this answer is correct because…
6. Which of these situations would lead to a
decrease in the number of producers in an
ecosystem?
A. an increase in the number of predators.
B. an increase in the number of herbivores.
C. an increase in the number of
decomposers.
D. none of the above.
I know this answer is correct because…
7. How do decomposers help reshape the
landscape?
A. Decomposers are consumed by plants and
help them grow faster.
B. Decomposers eat live plants and animals,
reducing their population.
8. The diagram below shows a salt marsh food
web.
Which of these
food chains
correctly
represents the
flow of energy
from one
organisms to the
next within this
food web?
A.
B.
C.
D.
cordgrassfungussnails
fishblue crabsterrapins
cordgrasssnailsfish
terrapinssnailsfungus
I know this answer is correct because…
9. Producers living in a grassland capture 2000
kilocalories of energy. These producers are
eaten by primary consumers, such as
grasshoppers. The grasshoppers are eaten by
secondary consumers, such as birds. Eventually,
how many of these 2000 kilocalories will be
stored in the body tissues of secondary
consumers?
A.
B.
C.
D.
20
200
2000
20000
I know this answer is correct because…