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EOC Practice: Interdependence



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

 1. 

In marine ecosystems, a decrease in secondary consumers could cause a decrease in primary producers.  A marine food pyramid is shown below.
mc001-1.jpg
What would best explain the decrease in primary producers?
a.
an increase in solar energy
c.
a decrease in the population of tertiary consumers
b.
a decrease in oxygen levels in the water
d.
an increase in the population of primary consumers
 

 2. 

A tundra food web is shown below.
mc002-1.jpg
What would most likely happen if the lemming population significantly decreased?
a.
The bird population would increase.
c.
The ermine population would decrease.
b.
The rabbit population would increase.
d.
The arctic fox population would decrease.
 

 3. 

A desert food chain is shown below.
mc003-1.jpg

What would likely be the result if a pesticide is used to reduce the number of harvester ants?
a.
an increase in snakes and a decrease in hawks
c.
a decrease in mesquite bushes and an increase in horned lizards
b.
a decrease in snakes and an increase in hawks
d.
an increase in mesquite bushes and a decrease in horned lizards
 

 4. 

A lightning strike causes a grass line that burns the producers in a grassland ecosystem.  What would best explain why some of the primary consumers are unaffected by the grassfire?
a.
They live in burrows.
c.
They can survive by only drinking water.
b.
They climbed up trees.
d.
They are able to produce their own food.
 

 5. 

Global warming has led to a decrease in ice in both the Arctic and Antarctic regions.  The table below show some animals in these areas an how they use their habitat.
mc005-1.jpg
Which population of animals would be least affected by global warming?
a.
polar bear
c.
emperor penguin
b.
ringed seal
d.
chinstrap penguin
 

 6. 

Pond ecosystems require nitrogen, phosphorus, and potassium in order to support the growth of algae.  This increase in algal growth can cause in increase in decaying matter in the pond.  What long-term effect might an increase in algal growth have on a pond ecosystem?
a.
an increase of the fish population in the ecosystem
c.
a population increase in other producers, such as water lilies, in the ecosystem
b.
an increase in available food for the fish in the ecosystem
d.
a decrease in the amount of available oxygen necessary for fish in the ecosystem
 

 7. 

Red-cockaded woodpeckers feed by pecking away the bark of old-age living pine trees and eating insects found below the bark.  They also require old-age living pine trees to make their nesting and roosting cavity.  Young and dead pine trees are not suitable habitats or suitable foraging materials for these birds.  Additionally, if the tree they are nesting in dies or if the shrub under-story of the area approaches the height of the cavity in the tree, they will abandon the tree.  The carrying capacity of the red-cockaded woodpeckers would be positively affected by an increase in which organism?
a.
dead pine trees
c.
young living pine trees
b.
high shrub under-story
d.
old age living pine trees
 

 8. 

A population of rabbits is below the carrying capacity in a forest habitat that has many resources and few predators.  Which statement best describes what could happen to the rabbit population during a period of time?
a.
The population of rabbits will remain stable.
c.
The rabbits will become susceptible to disease which will decrease the population.
b.
Some rabbits will migrate to find additional resources.
d.
The population of rabbits will increase in the absence of adverse environmental pressures.
 

 9. 

Human-built dams across rivers have both positive and negative effects on the environment.  What effect does building dams have on environments downstream?
a.
a positive effect due to increasing the natural flow of nutrients
c.
a positive effect due to reducing populations of non-native species
b.
a negative effect due to decreasing the natural flow of nutrients
d.
a negative effect due to increasing the populations of native species
 

 10. 

Forest fires are often started by lightning.  In the past, forestry services would extinguish the fires before they spread.  Today, many forestry services practice controlled burning of forests  What is the most likely reason forestry practices have changed?
a.
Controlled burnings return nutrients to the soil.
c.
Controlled burnings maintain the population growth of animal species.
b.
Controlled burnings prevent the logging of trees.
d.
Controlled burnings increase the amount of water runoff after a storm.
 

 11. 

Lake trout are freshwater fish that inhabit many of the Great Lakes.  In the 1830’s humans built canals and locks from the Atlantic Ocean to the Great Lakes to increase trade.  The canals and locks enabled invasive sea lamprey to enter the Great Lakes.  In 1958 biologists began applying a chemical into streams flowing into Lake Superior that was specifically toxic to sea lampreys. The graph shows the population of lake trout in Lake Superior during a 65-year period.
mc011-1.jpg
What most likely would have happened if the sea lamprey population was not controlled?
a.
The lake trout might have developed immunity to the sea lamprey.
c.
The lake trout would have migrated to the Atlantic Ocean.
b.
The lake trout might have become extinct in Lake Superior.
d.
The lake trout would have increased reproductively.
 

 12. 

Coral reefs are important to many ocean ecosystems because they provide food and shelter for numerous marine organisms.  Climate changes that lead to increased water temperatures can slow the growth of coral.  Scientists monitor the physical conditions and species distribution of coral reefs and try to temporarily alter conditions when they are harmful to coral reefs. Which of these actions by scientists would best accomplish the goal of preserving coral reefs?
a.
protect the biodiversity of coral reefs
c.
isolate predators from coral reef organisms
b.
restrict regulations concerning coral reefs
d.
identify new species associated with coral reefs
 

 13. 

Which human activity would most likely cause the biggest long-term threat to the biodiversity in a forest ecosystem?
a.
burning a section of trees to stop a fire
c.
planting native species on abandoned farmland
b.
constructing a road through the forest
d.
cutting down infected trees to stop the spread of a disease in the forest
 

 14. 

Reindeer, caribou, arctic foxes, mosses, and lichens are just a few of the organisms that live in the tundra and depend on it for habitat and food.  Which environmental change would most likely affect the biodiversity of the tundra?
a.
decrease in floods
c.
decrease in wildfires
b.
increase in farming
d.
increase in temperatures
 

 15. 

Biodiversity is important because it boosts the productivity of an ecosystem. Each species has an important role.  For example, honeybees are necessary for plant biodiversity.  In recent years, the number of honeybees has declined significantly.. How does the decline in the number of honeybees most affect plant biodiversity?
a.
Fewer pollinators mean less plant reproduction.
c.
Less carbon dioxide from bees leads to a decrease in photosynthesis by plants.
b.
Less honey production leads to a reduced amount of food for plants.
d.
Fewer honeybees lead to the extinction of the most common, widespread plants.
 

 16. 

The oak savanna ecosystem is dependent on wildfires and controlled burnings to manage the growth of invasive and nonnative shrubs and trees and to help maintain the native semi-open ecosystem.  Which statement best describes the impact invasive plant species could have if not maintained by fires?
a.
They could decrease the populations of native plant and animal species.
c.
They could increase the amount of food available to native plant and animal species.
b.
They could decrease the amount of oxygen available for the native animals
d.
They could increase the amount of nitrogen in the soil that is toxic to the native plants.
 

 17. 

The population of the Karner blue butterfly has decreased by 99%.  Karner butterfly larvae feed only on the leaves of the blue lupine.  Blue lupines grow in dry, sandy soils found in oak savannas and pine barrens.  The habitat of blue lupines is maintained by wildfires, prescribed burns, mowing, and grazing.  Which activity would lead to a further decrease in the population of Karner blue butterflies?
a.
initiating state burning bans
c.
decrease in the number of blue lupine competitors
b.
increased logging of pine forests
d.
planting large amounts of blue lupines in oak savannas
 

 18. 

A fish species depends on high oxygen concentration in lake water.  How could an increase i photosynthetic algae concentration in the water trigger the extinction of this fish species?
a.
The algae could alter water pH by excreting wastes, making oxygen less soluble in the water.
c.
The algae could produce material leading to an increase in decomposer populations, which would deplete available oxygen.
b.
The algae could block enough sunlight that the water cools, reducing the amount of oxygen the water can hold.
d.
The algae could directly compete with the fish for oxygen, which would gradually eliminate the fish due to algae’s ability to reproduce rapidly.
 

 19. 

A region has average winter temperatures of 2 degrees Celsius.  A climate change results in a drop in winter temperature to an average of -8 degrees Celsius.  A mammal species lives in the region.  Which property in the species would most likely cause the mammal to become extinct as a result of the climate change?
a.
The species grows a thicker winter coat of fur and a thinner summer coat of fur.
c.
The species has relatively unvarying white fur.
b.
The species grows a whiter winter coat of fur and a browner summer coat of fur.
d.
The species has relatively unvarying thin fur.
 

 20. 


The diagram shows an example of primary succession.
mc020-1.jpg
Which factor is responsible for beginning the process of change in the ecosystem from Diagram 1 to Diagram 4?
a.
climate cooling in the area
c.
breakdown of rocks by pioneer plants
b.
organic matter from producers
d.
action of roots by large trees in the area
 

 21. 

Primary succession occurs in a place where an ecosystem has not been established.  Which occurrence represents a first step in the process of primary succession?
a.
a forest of pine trees develops
c.
a forest of shade trees develops
b.
grasses and shrubs appear
d.
lichens appear on bare rocks
 

 22. 

Which of these factors is most important for reestablishing plants and trees on an abandoned farm?
a.
ATP and xylem
c.
glucose and vitamins
b.
oxygen and nitrogen
d.
sunlight and carbon dioxide
 

 23. 

In the 1930s, wolves in Yellowstone National Park ere eliminated after many years of hunting.  The wolves were reintroduced into Yellowstone National Park in 1995.  The illustration below depicts a food web in Yellowstone National Park.
mc023-1.jpg
What effect did the reintroduction of wolves into Yellowstone likely have on this ecosystem?
a.
The elk population decreased.
c.
The songbird population decreased.
b.
The red fox population decreased.
d.
The willow tree population decreased.
 

 24. 

The following diagram represents a food pyramid.
mc024-1.jpg
A decrease in the frog population would most likely lead to an increase in the population of which organism?
a.
Owl
c.
Snake
b.
Grass
d.
Grasshopper
 

 25. 

Duckweed is a floating plant commonly found growing on the surface of ponds.  During favorable conditions, the population of this plant can increase quickly and cover the entire surface of a pond.
mc025-1.jpg
What effect would an increase in duckweed have on a pond ecosystem?
a.
The duck population would decrease due to a lower food supply.
c.
The underwater plant population would decrease due to decreased sunlight.
b.
The fish population would increase due to an increased food supply.
d.
The algae population would increase due to higher levers of oxygen in the water.
 

 26. 

The illustration below shows an ecosystem in the Southern Plains.
mc026-1.jpg
How would a drought in the Souther Plains most likely affect the quail population?
a.
a decrease in the quail population due to a decrease in nesting cover
c.
a decrease in the quail population due to a decrease in the mouse population
b.
an increase in the quail population due to a decrease in insect population
d.
an increase in the quail population due to a decrease in the rabbit population
 

 27. 

Drought in an ecosystem results in decreased populations of primary consumers.  What would best explain the decrease in primary consumers?
a.
A decrease in wind speeds
c.
An increase in airborne pathogens
b.
A decrease in primary producers
d.
An increase in secondary consumers
 

 28. 

White-tailed deer prefer to live in wooded areas.  Their diet consists of grasses, shrubs, and other small forage plants.  White-tailed deer are prey to animals such as coyotes, bobcats, and wolves.  These deer are also the most important hosts for a parasite, the deer tick, and are critical for deer tick survival.  Larvae of the deer tick feed on birds and smaller mammals.  How would the carrying capacity of other organisms in the ecosystem change if the white-tailed deer population decreased?
a.
The carrying capacity of shrubs would decrease.
c.
The carrying capacity of deer tick larvae would increase.
b.
The carrying capacity of coyotes would increase.
d.
The carrying capacity of adult deer ticks would decrease.
 

 29. 

Populations of white-tailed deer live in an ecosystem hat has an abundant food supply of woody-type plants with minimal supplies of grasses and weeds. The table shows the typical diet composition of white-tailed deer in this type or ecosystem as well as other animals frequently introduced into this type of ecosystem.
mc029-1.jpg
Introduction of which animal into this type of ecosystem would most likely affect the carrying capacity of the white-tailed deer population?
a.
Cattle
c.
Fallow Deer
b.
Sheep
d.
Nilgai Antelope
 

 30. 

To reduce erosion in an area, an exotic fast-growing vine is introduced into the area without any growth control.  How will the new plant most likely have an effect on the ecosystem?
a.
The vine will provide protection for native plants.
c.
The vine will compete with native plants for sunlight and space.
b.
The vine will provide more wood for use in the area.
d.
The vine will compete with native animals for food, water and minerals.
 

 31. 

In 1906, the Grand Canyon National Game Preserve was established on the Kaibab Plateau in Arizona.  Regulations prohibited deer hunting but allowed some hunting of mountain lions, coyotes, ad bobcats.  What most likely resulted from the hunting regulations within the preserve?
a.
The deer population grew too large for the area to support.
c.
Invasive plant species became established.
b.
The carrying capacity of the area immediately decreased.
d.
Predator population became extinct.
 

 32. 

Freshwater mussel species have specific habitat requirements regarding the temperature and quality of water. They are filter feeders that live in shallow areas of free-flowing streams.  During the mussel life cycle, specific fish species are used as hosts for their microscopic larval stage.  Which environmental change would most likely contribute to the extinction of mussel species?
a.
building a dam near the source of a river
c.
increasing microscopic nutrients in streams
b.
stocking rivers and streams with host fish
d.
increasing stream water flow by clearing debris
 

 33. 

The spring-fed San Marcos River and Spring Lake in central Texas are home to the endangered fountain darter. Fountain darters require dense bottom plant cover for hiding and breeding.  The giant ramshorn snail is an invasive, non-native species that eats large amounts of fountain darter habitat plants.  The giant ramshorn snail population increases during times when spring flows are low.  If a lengthy drought occurs in this region, what will most likely be the effect on fountain darters?
a.
Grazing species will disappear, leaving more habitat cover for fountain darters.
c.
Fountain darters will adapt to the environmental change by producing hybrid species.
b.
Due to habitat loss from giant ramshorn snail competition, fountain darters may become extinct.
d.
The drought will cause fountain darters to seek other types of cover for reproduction.
 

 34. 

The figures below show the changes in a pond over time.
mc034-1.jpg
What event is responsible for the initial changes in the pond?
a.
colonization of the pond by plants
c.
a change in water temperature of the pond
b.
accumulation of sediment in the pond
d.
increased activity of decomposers in the pond
 

 35. 

Which event would led to primary succession?
a.
the logging of a forest
c.
an abandoned farm
b.
the melting of a glacier
d.
an open area caused by a forest fire
 



 
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