Name: 
 

LE Ecology Online Review



Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
 

1. 

A food web is more stable than a food chain because a food web
A.
transfers all of the producer energy to herbivores
B.
reduces the number of niches in the ecosystem
C.
includes alternative pathways for energy flow
D.
includes more consumers than producers
 

2. 

The diagram below shows changes that might occur over time after a fire in a forest area.
le_ecology_review_files/i0030000.jpg
Which statement is most closely related to the events shown in the diagram?
A.
The lack of animals in an altered ecosystem speeds natural succession.
B.
Abrupt changes in an ecosystem only result from human activities.
C.
Stable ecosystems never become established after a natural disaster.
D.
An abrupt environmental change can cause a long-term gradual change in an ecosystem.
 

3. 

The diagram below illustrates the relationships between organisms in an ecosystem.
le_ecology_review_files/i0040000.jpg
Which change would most likely reduce the population size of the carnivorous fish?     
A.
a decrease in the duck population
B.
an increase in the raccoon population
C.
a decrease in pathogens of carnivorous fish
D.
an increase in the autotroph populations
 

4. 

The diagrams below show some changes in an environment over time.
le_ecology_review_files/i0050000.jpg

Which phrase best describes this sequence of diagrams?
A.
the path of energy through a food web in a natural community
B.
the altering of an ecosystem by a natural disaster
C.
natural communities replacing each other in an orderly sequence
D.
similarities between an aquatic ecosystem and a terrestrial ecosystem
 

5. 

The chart below shows the environmental functionsthat some organisms perform in a stable ecosystem.
le_ecology_review_files/i0060000.jpg
How would a decrease in the number of organisms that perform these functions most likely affect the ecosystem?
A.
The interactions between other organisms would stop immediately.
B.
The functions carried out by these organisms would no longer be necessary.
C.
The ecosystem would remain stable.
D.
The ecosystem would become less stable.
 

6. 

"Natural ecosystems provide an array of basic processes that affect humans."
Which statement does not support this quotation?
A.
Bacteria of decay help recycle materials.
B.
Trees add to the amount of atmospheric oxygen.
C.
Treated sewage is less damaging to the environment than untreated sewage.
D.
Lichens and mosses living on rocks help to break the rocks down, forming soil.
 

7. 

A food pyramid representing relationships in a pond community is shown below.
le_ecology_review_files/i0080000.jpg
The energy of the Sun is made available to the pond community through the activities of the organisms at level
A.
A
B.
B
C.
C
D.
D
 

8. 

The diagram below represents an energy pyramid.
le_ecology_review_files/i0090000.jpg
Which organisms would most likely be found at level A?
A.
birds
B.
mammals
C.
worms
D.
algae
 

9. 

The dense needles of Douglas fir trees can prevent most light from reaching the forest floor. This situation would have the most immediate effect on
A.
producers
C.
carnivores
B.
herbivores
D.
decomposers
 

10. 

An ecosystem will most likely remain stable if
A.
it has more predators than prey
C.
biotic factors decrease
B.
it has a high level of biodiversity
D.
finite resources decrease
 

11. 

The diagram below represents part of a life process in a leaf chloroplast.
le_ecology_review_files/i0120000.jpg
If the process illustrated in the diagram is interrupted by a chemical at point X, there would be an immediate effect on the release of
A.
chlorophyll
B.
carbon dioxide
C.
nitrogen
D.
oxygen
 

12. 

The diagram below represents a model of a food pyramid.
le_ecology_review_files/i0130000.jpg

Which statement best describes what happens in this food pyramid?
A.
More organisms die at higher levels than at lower levels, resulting in less mass at higher levels.
B.
Energy is lost to the environment at each level, so less mass can be supported at each higher level.
C.
When organisms die at higher levels, their remains sink to lower levels, increasing the mass of lower levels.
D.
Organisms decay at each level, and thus less mass can be supported at succeedingly higher levels.
 

13. 

A student hypothesized that lettuce seeds would not germinate (begin to grow) unless they were covered with soil. The student planted 10 lettuce seeds under a layer of soil and scattered 10 lettuce seeds on top of the soil. The data collected are shown in the table below.
le_ecology_review_files/i0140000.jpg
To improve the reliability of these results, the student should
A.
conclude that darkness is necessary for lettuce seed germination
B.
conclude that light is necessary for lettuce seed germination
C.
revise the hypothesis
D.
repeat the experiment using a larger sample size
 

14. 

A student designed an investigation to determine the effect of temperature on the rate of seed germination. The student placed moist filter paper in each of four culture dishes. Ten bean seeds were placed on the filter paper in each dish. The four dishes were numbered and placed in the dark at different temperatures as follows:
   Dish 1:10°C,   Dish 2: 15°C,   Dish 3: 20°C,   Dish 4: 25°C.
The total number of germinated seeds in each culture dish was counted each day for two weeks.
Which data table is best for recording the results of this investigation?
A.
le_ecology_review_files/i0150000.jpg
C.
le_ecology_review_files/i0150001.jpg
B.
le_ecology_review_files/i0150002.jpg
D.
le_ecology_review_files/i0150003.jpg
 

Short Answer
 

15. 

A food web is shown below.
le_ecology_review_files/i0170000.jpg
State what would happen to the plant population if the number of decomposers decreased and explain why this would happen.
 
 
For each description in the following questions, select the interaction, chosen from the list below, that is most closely associated with that description. Then record its number in the space below the description. An answer may be used more than once or not at all.
le_ecology_review_files/i0180000.jpg
 

16. 

Ants (organism A) defend acacia trees (organism B) from attacks by insects that are herbivores. The ants live in the hollow thorns of the trees.
 

17. 

The rhinoceros bird (organism A) feeds on parasites that live on the body of a rhinoceros (organism B). The rhinoceros allows the birds to feed on the parasites.
 

18. 

Wasp larvae (organism A) obtain nutrition from tomato hornworms (organism B). The tomato hornworms do not survive.
 

19. 

How do guard cells of a leaf help to maintain homeostasis in a plant?
 

20. 

Identify one process that a producer can accomplish that a carnivore can not accomplish.
 



 
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