Populations and Ecosystems

A population of mice lives in the northeastern United States. Over the last 50 years, the size of the mouse population decreased. What best explains the decrease in the size of the mouse population?

• Fewer mice were born than died

• All the mice die and no mice were born

• More mice were born than died

• Lots of mice immigrated into the population

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NGSS.MS-LS2-1

NGSS.MS-LS2-4

When an environment has reached its carrying capacity for a certain population, which of the following is true?

• Birth rate and immigration rate are equal death rate and emigration rate

• Birth rate and immigration rate are greater than death rate and emigration rate

• Birth rate and immigration rate are less than death rate and emigration rate

• Birth rate is exponential

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NGSS.MS-LS2-1

NGSS.MS-LS2-4

What is the approximate carrying capacity for the deer population in the graph?

• 100

• 80

• 60

• 20

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NGSS.MS-LS2-1

NGSS.MS-LS2-4

Which of the following describes how an abiotic factor can impact the population in an ecosystem?

• A parasite that invades a host can reproduce and cause a decline in the host species population.

• Organisms that compete for the same resources will keep each other from overpopulating.

• Predators will prevent herbivores from depleting the plants and other resources in an ecosystem.

• Seasonal variations in temperature can cause some of the individuals in a population to die.

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NGSS.MS-LS2-4

Which pair of factors is most likely to increase the size of the population?

• births and deaths

• births and immigration

• deaths and emigration

• immigration and emigration

A population of kangaroos grows briefly and then stabilizes. What does the leveling off indicate?

• The population has reached the carrying capacity of the environment.

• The population has exceeded the carrying capacity of the environment.

• The population is affected by a density-independent limiting factor.

• The population is no longer able to adapt to environmental changes.

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NGSS.MS-LS2-1

NGSS.MS-LS2-4

Which of the following is a density-dependent limitation of population growth?

• A forest fire

• Competition with other organisms for resources

• Pollution in the water

• Drought (greatly reduced rainfall)

Tags

NGSS.MS-LS2-1

A disease kills most of the predator population. Which of these is the most likely effect on the prey population?

• The prey will also be killed by the disease.

• The prey population will decrease in size because there are fewer predators.

• The prey population will increase in size because there are fewer predators.

• There will be no effect on the prey population.

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NGSS.MS-LS2-2

NGSS.MS-LS2-4

Corals live near the surface of the ocean in some warm regions of the world. The corals provide a home for algae. The algae, in turn, produce food that is used by the corals. Which is a biotic factor in this ecosystem?

a. The temperature of the water

b. The (salinity (salt content) of the water

c. The size of the algae population

d. The amount of sunlight that reaches the coral.

• The temperature of the water

• The (salinity (salt content) of the water

• The population of algae

• The amount of sunlight that reaches the coral.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

What is the name given to lichen or algae after a primary succession?

• pioneer species
• volunteer species
• founder species
• conqueror species

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NGSS.MS-LS2-3