Question 1

If you gave N₂ to a culture of nitrogen-fixing bacteria,you would expect to detect

Accepted Answer

Nitrogen-fixers like Rhizobium first produce ammonia.Please see section 19.7 for more information.

Question 2

______ bacteria return nitrogen to the atmosphere by converting nitrates to N₂.

Accepted Answer

In denitrification,different bacteria than those which fixed the nitrogen obtain energy by returning the nitrogen to the atmosphere.Please see section 19.7 for more information.

Question 3

If you wanted to know the total amount of energy taken into an ecosystem,you would look at the primary producers since it is the primary producers that are responsible for

Accepted Answer

The energy entering an ecosystem,usually from the sun,comes in via primary producers,almost all of that are photosynthetic.Please see section 19.6 for more information.

Question 4

In the water cycle,animals return water to the environment by

Accepted Answer

Animals release water into the environment when they breathe out and when they excrete wastes.Please see section 19.7 for more information.

Question 5

Which is not an important biogeochemical cycle on Earth?

Accepted Answer

whiLE ATp production is critical,it does not occur IN the earth at any point,and thus is not a biogeochemical cycle.Please see section 19.7 for more information.

Question 6

A food chain is a series of organisms that

Accepted Answer

Food chains pass energy and nutrients from producers to various levels of consumers.Please see section 19.6 for more information.

Question 7

As an overall average,about ______ of the energy at one trophic level is generally available to the next highest rank in the food chain.

Accepted Answer

In an ecosystem with four levels,only about one thousandth of the originally-captured energy is available to the top-level consumers.Please see section 19.6 for more information.

Question 8

Organisms that obtain their energy from producers or other consumers are

Accepted Answer

Heterotrophs obtain reduced carbon compounds and energy by eating other organisms.Please see section 19.6 for more information.

Question 9

Walleye pike fish are what?

Accepted Answer

Tertiary consumers are the fourth level in a food chain.Please see section 19.6 for more information.

Question 10

You are blindfolded and led to dry landscape where you see wind picking up sand and grinding it against a cliff.You are asked which biogeochemical cycle could be observed,and you answer that it is the _______ cycle.

Accepted Answer

The phosphorous cycle starts with the weathering of rock.Please see section 19.7 for more information.

Question 11

Which ecosystem has a very high net primary productivity?

Accepted Answer

The ecosystems with the highest net primary productivity are those with the greatest availability of nutrients,light,and water.Please see section 19.6 for more information.

Question 12

Carbon returns to the atmosphere

Accepted Answer

Carbon is used in many ways and can,thus,find its way back to the atmosphere in many ways.Please see section 19.7 for more information.

Question 13

An organism's ______ is its position in the food chain relative to the ecosystem's energy source.

Accepted Answer

Trophic levels are different levels in food webs,with few organisms and energy usually available at higher and higher levels.Please see section 19.6 for more information.

Question 14

"Net primary productivity" is the amount of energy

Accepted Answer

Net primary productivity is the difference between the capture by primary producers and their own use of energy.Please see section 19.6 for more information.

Question 15

Biomagnification occurs with chemicals that

Accepted Answer

Biomagnification occurs when molecules are passed up the food web and retained at higher and higher concentrations.Please see section 19.6 for more information.

Question 16

An organism that can use solar energy and inorganic substances to produce all the organic material it requires is a(an)

Accepted Answer

Producers use energy from an inorganic source to provide the base of the food chain,and autotrophs can make all of the organic molecules which they need from inorganic precursors.Please see section 19.6 for more information.

Question 17

Secondary consumers are

Accepted Answer

Secondary consumers eat other consumers.Please see section 19.6 for more information.

Question 18

Decomposers

Accepted Answer

Decomposers are often microbes,working to extract energy and nutrients from dead material.Please see section 19.6 for more information.

Question 19

If you were to shine a lightbulb on a puddle,and the water in the puddle disappeared,you would say that you had added energy to the puddle and had seen

Accepted Answer

Evaporation of abiotic water returns it to the atmosphere.Please see section 19.7 for more information.

Question 20

Zooplankton are what?

Accepted Answer

Zooplankton eat phytoplankton,the primary producers in many aquatic ecosystems.Please see section 19.6 for more information.

Quiz 19: Communities and Ecosystems

If you gave N2 to a culture of nitrogen-fixing bacteria,you would expect to detect

______ bacteria return nitrogen to the atmosphere by converting nitrates to N2.