6TH GRADE CSA #7

Which statement best outlines an essential truth about biotic and abiotic factors?

• Organisms in a ecosystem can survive without biotic factors but not without abiotic factors.

• All biotic factors in an ecosystem depend on abiotic factors.

• All abiotic factors in an ecosystems depend on biotic factors.

• Organisms is an ecosystem can survive without abiotic factors but not without biotic factors.

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NGSS.MS-LS2-3

In the 1940's, the chemical DDT was used as a pesticide to control mosquito populations in different areas of the world.  The use of this chemical contributed to a decrease in eagle populations due to weak egg shells that broke or eggs that did not hatch.  An example of an ecosystem that includes eagles is shown in the model.

Based on the information in the model, which statement best explains how DDT was introduced into eagle populations?

• The eagles absorbed the DDT after eating large fish.

• The eagles absorbed the DDT directly form the water.

• The eagles absorbed the DDT directly from the air.

• The eagles absorbed the DDT after eating zooplankton.

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NGSS.MS-LS2-4

NGSS.MS-LS1-5

Based on the diagram, it is reasonable to conclude that matter could follow which of the following paths as it cycles through this ecosystem?

• sun --> grass --> robin

• grass--> deer--> mountain lion

• plant seeds --> field mouse --> robin

• eagle --> deer--> plant seeds

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NGSS.MS-LS2-3

NGSS.MS-LS1-6

Matter is passed from the living part of an ecosystem to the non-living part when which of the following takes place?

• Animals drink water.

• Animals eat plants.

• Plants absorb gases.

• Plants decompose into soil.

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NGSS.MS-LS2-3

The energy organisms need to live and grow first enters the ecosystem when_________________.

• secondary consumers eat primary consumers.

• decomposers break down dead organisms.

• plants take in light energy from the Sun.

• primary consumers eat plants for food.

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NGSS.MS-LS2-3

NGSS.MS-LS1-6

One world-wide concern is the removal of forests to make space for farms and other human activities.

Which statement best explains how the removal of trees from Earth upsets the carbon cycles?

• The cycle is not affected.  There are many other green plants that have the same role as trees in the carbon cycle.

• More carbon enters the cycle, reducing CO₂ in the air.

• Less carbon is pulled from the air and made available to living things.

• Decomposers increase because they no longer compete with trees for carbon.

  Decomposers increase because they no longer compete with trees for carbon.

Tags

NGSS.MS-LS2-3

NGSS.MS-LS1-6

Interdependent Relationships in Ecosystems

Aggressive behavior often occurs when individuals or groups of individuals are in competition with one another. Competition is rivalry between individuals or groups over something that both sides want or need. Competition occurs naturally between living organisms that coexist in the same environment.

A student wants to investigate competition between two organisms.

For the investigation, it is most important that the student should choose organisms that ____________.

• reproduce at the same rate

• require the same resources.

• are both active during the day

• have the same adaptations.

Tags

NGSS.MS-LS2-1

The graph here shows the populations, over several years, for two animals that share the same habitat.  Foxes are mammals that hunt for food, and grouse are birds, a common prey animal of foxes.

According to the data, in which year did the population of foxes show decrease that is most likely the result of a decrease in the availability of a source of food?

• 2005

• 2003

• 2008

• 2012

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

Based on the relationship between monarchs and milkweed, which of the following trends would be predicted when looking at data on the populations of these two organisms?

• Population increase in monarch butterflies should follow population decrease in milkweed.

• Population decrease in monarch butterflies should follow population decrease in milkweed.

• Population of milkweed should remain constant when monarch butterfly population increases.

• Population of monarch butterflies should remain constant when milkweed population decreases.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4

NGSS.MS-LS2-2

The population of deer in a certain area is monitored over a period of six years. 

The data is represented in the graph provided.

Which of the following is the most likely explanation for the change in population in 2009?

• Rainfall in the previous spring was higher than the yearly average.

• Humans introduced grazing animals that feed on the same plants as the deer.

• More insects that pollinate flowering plants move into the habitat.

• Wolves, which prey on deer, were being hunted more than usual.

Tags

NGSS.MS-LS2-1

NGSS.MS-LS2-4