Populations and Ecosystems

The picture shows a forest ecosystem. Which scenario demonstrates the interaction of biotic and abiotic factors in this ecosystem?

• bear eating fish

• wolf walking on grass

• sunlight shining on dirt

• birds flying in the air

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Scientists have discovered that there has been a decrease in the bumblebee population in a specific area. They have noticed that the carrying capacity for bumblebees has declined. If the scientists want to increase the population of the bumblebees, what should they suggest?

• plant more flowers

• remove the producers from the ecosystem

• spray insecticides

• increase soil erosion

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Changes to abiotic factors in an ecosystem can affect the biotic factors within the same ecosystem. Which statement is an example of this situation?

• Melting glaciers cause an increase in water levels.

• Decreased rainfall increases competition among consumer.

• Drought decreases soil erosion.

• Warmer temperatures decrease the weathering of rocks.

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When a predator from a specific location is removed, what would most likely cause the prey population in that same area to increase?

• competing species moves into the ecosystem

• humidity increases

• amount of available food remains the same

• water supply decreases

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Changes in the population of moths are shown in the graph. What is the most likely reason for the decline in moths from 2012-2013?

• competition for resources increased

• predators moved out of the environment

• more habitat space became available

• reproduction rate stabilized

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The graph shows the populations of snowy owls and lemmings in a specific area. In which year were the habitat of both most likely destroyed?

• 1998

• 2006

• 2009

• 2013

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The diagram shows a food web of a grassland ecosystem. The removal of the hawk from the area led to overgrazing by the rabbits. Why would it be important for the hawk to be reintroduced back into the ecosystem?

• It will maintain the flow of energy in the food web of the ecosystem.

• It will maintain the populations of the ecosystem.

• It will decrease the population of predators within the ecosystem.

• It will decrease the biodiversity of the park.

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Examine the food chain. An organism that feeds on grasshoppers moves into the area. Which consequence is likely to occur first?

• The population of mice will decrease.

• The population of grasshoppers will increase.

• The grass population will be unaffected.

• The population of owls will increase.

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A herd of elk migrate into a forest ecosystem. Which statement describes a possible negative effect of this migration on the forest environment?

• The forest will thrive because of a new species being introduced.

• The population density will decrease.

• The elk will bring new resources to the forest.

• The population density will increase.

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Use the food web of the ocean ecosystem to answer the question. What would be the most likely effect on the food web if the coral population suddenly decreased significantly?

• The unicornfish population will decrease.

• The parrotfish population would decrease.

• The phytoplankton population will increase.

• The shark population would increase.

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