Biology Keystone Ecology

A group of students measured a ten-square-meter section of a pond ecosystem and recorded observations. Which statement is a testable hypothesis?

• The frogs living in the pond represent a population
• Water is an abiotic component in the pond ecosystem
• If the fish are given more food, then they will be happier
• If the frogs are startled, then they will jump into the water

 Which term best classifies all of the observations?  Observations:  two grey wolves, five moose, several species of conifer trees, large granite rock and shallow pond.

• population
• food chain
• ecosystem
• community

A researcher observing an ecosystem describes the amount of sunlight, precipitation, and type of soil present. Which factors is the researcher most likely describing?

• biotic factors in a forest
• biotic factors in a tundra
• abiotic factors in a prairie
• abiotic factors in an ocean

A species of snapping turtles has a tongue that resembles a worm. The tongue is used to attract small fish. Which best describes the interaction between the fish and the snapping turtle?

• predation
• symbiosis
• parasitism
• competition

Which statement correctly describes how nitrogen in the soil returns to the atmosphere?

• Soil bacteria convert nitrates into nitrogen gas
• Decomposers directly convert ammonium into nitrogen gas
• Plants assimilate nitrites and convert them into nitrogen gas
• Nitrogen-fixing bacteria in plant roots convert nitrates into nitrogen gas

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Which sequence correctly describes the flow of energy between organisms in the marine food web?

• from seals to penguins to krill
• from whales to krill to small fish
• from sea birds to seals to penguins
• from small fish to penguins to seals

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Agricultural runoff can carry fertilizers into lakes and streams. This runoff can cause algae populations to greatly increase. Which effect does this change in the algae population sizes most likely have on affected lakes and streams?

• an increase in water level
• an increase in water clarity
• a reduction in dissolved oxygen needed by fish and shellfish
• a reduction in temperature variations near the water’s surface

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A farmer observed that an increase in a field’s soil nitrogen content was followed by an increase in producer productivity. What does this observation most likely indicate about the relationship between nitrogen and the producers in the field?

• Nitrogen was a biotic factor
• Nitrogen was a limiting factor
• Nitrogen became a surplus resource
• Nitrogen became a selection pressure

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What interaction is shown between the lion and the zebra in the picture?

• predation
• parasitism
• commensalism
• mutualism

Mute Swans are one of the heaviest flying birds and consume up to 8 pounds of vegetation each day. How will the migration of Mute Swans into an area most likely affect the birds native to that area?

• The native birds and the Mute Swans will coexist peacefully together
• The native birds will immediately migrate to another area
• The native birds will decrease in number because there is not enough food for all the birds
• The native birds will adapt to consume less food or different types of food

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