Ecosystems Flashcards

1
Q

What four things do biological communities interact with?

A

1) climate
2) soil
3) atmosphere
4) water

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2
Q

The four things that make up an ecosystem are _________

A

1) physical environment
2) individual behavior
3) population ecology
4) community ecology

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3
Q

How are populations in an ecosystem labeled?

A

By how they fit into trophic interactions

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4
Q

Trophic interactions are _________

A

feeding interactions between species

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5
Q

What are producers?

A

Species that produce energy

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6
Q

What are the two main types of producers?

A

1) primary producer
2) secondary producer

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7
Q

A primary producer is _________

A

a species that captures energy in the form of sunlight or inorganic molecules and builds it into chemical bonds through photosynthesis or chemosynthesis

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8
Q

Primary producers form _______ matter from ________ matter using energy gained from _______ resources

A

organic; inorganic; outside

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9
Q

Which of the following is true regarding primary production?

A) Can be fueled by light or chemical reactions

B) Is the conversion of inorganic to organic matter

C) Is typically followed by secondary production (heterotroph production)

D) Creates organic matter from organic matter

E) Is the basis of most food webs and chains

A

A) Can be fueled by light or chemical reactions

B) Is the conversion of inorganic to organic matter

C) Is typically followed by secondary production (heterotroph production)

E) Is the basis of most food webs and chains

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10
Q

Secondary producers are __________

A

species that gain energy from primary producers and produce biomass

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11
Q

What is a consumer?

A

A species that gains energy from consuming other organisms

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12
Q

What are the two main types of consumers?

A

1) primary consumer
2) secondary consumer

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13
Q

A primary consumer is ___________

A

a species that eats primary producers

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14
Q

A secondary consumer is __________

A

a species that eats primary consumers

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15
Q

What is a detritivore?

A

A species that consumes dead organic matter

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16
Q

Humans are considered _________ because they feed on producers and consumers on multiple trophic levels.

A

omnivores

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17
Q

A ________ appears on the top level in the chain or web of feeding interactions.

A

top carnivore

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18
Q

What is a bottom-up impact?

A

A change at the lower trophic level that impacts the trophic levels above

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19
Q

What is a top-down impact?

A

A change at the top trophic level that impacts population size of lower trophic levels

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20
Q

An autotroph is a _________ and a heterotroph is a _________.

A

producer; consumer

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21
Q

What are the two primary production types?

A

1) gross primary production (GPP)
2) net primary production (NPP)

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22
Q

Gross primary production (GPP) is _______

A

the total quantity of primary production

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23
Q

When producers metabolize some of their acquired energy for their own growth and maintenance, the remainder of energy is called __________

A

net primary production (NPP)

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24
Q

Net primary production (NPP) is ________

A

the amount of energy resources that are left for consumers in an ecosystem to acquire through herbivory

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25
Q

Most NPP occurs in ________ with the particularly greatest NPP per unit area occurring in ________ and ________.

A

oceans; algal beds; coral reefs

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26
Q

The land community with the greatest NPP is the _________.

A

tropical rain forest

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27
Q

True or false?

Energy and matter both flow in the ecosystem.

A

False; energy FLOWS because usable energy is lost as heat in biological processes, but matter CYCLES because matter is conserved

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28
Q

The transfer of energy is not efficient because __________

A

organisms use some of the energy gained from digested matter for their own growth and reproduction

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29
Q

What are the two ways potential energy is spent during digestion?

A

1) through chemical processes
2) remaining in matter as it moves through organism’s digestive tract

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30
Q

______ of energy is lost at each trophic level transfer, meaning that only ______ is usable.

A

90%; 10%

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31
Q

How does the inefficiency of energy transfer affect the food web?

A

It limits the length of food chains

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32
Q

What four chemicals make up the matter in living organisms?

A

1) carbon
2) hydrogen
3) oxygen
4) nitrogen

33
Q

Matter in living organisms are either ______ into the consumer or _______ in the environment.

A

incorporated; left behind

34
Q

Energy obtained by organisms are _________ (3 answers).

A

1) used for maintenance of organism
2) used for growth and reproduction
3) lost as heat or excreted waste from the organism

35
Q

Since a large percentage of energy is lost as trophic levels increase, the predator population must be ______ than the producer population and biomass.

A

less

36
Q

What is biomass?

A

The combined mass of all organisms of a species or group in an ecosystem

37
Q

True or false?

Energy is transferred inefficiently, so chemical toxins must also be transferred inefficiently.

A

False; chemical toxins are always incorporated into the consumer from their food

38
Q

What is biomagnification?

A

The concentration of toxins in an organism as a result of consuming other organisms

39
Q

If the energy pyramid narrows as trophic levels increase, how can it be inverted?

A

If producers undergo rapid generation times and little investment in building a physical body

40
Q

Matter is stored in ________ such as carbon in rocks and plants.

A

compartments

41
Q

The movement of matter between compartments is called _____.

A

flux

42
Q

The four reasons why carbon fluxes are ________

A

1) respiration
2) photosynthesis
3) decomposition
4) burning

43
Q

Carbon cycles ______ through organisms but ______ through the environment.

A

quickly; slowly

44
Q

What is carbon sink?

A

An environment storing carbon that absorbs it at a greater rate than it releases it.

45
Q

True or false?

CO2 helps regulate temperature.

A

True

46
Q

CO2 _______ over time, but is balanced by global terrestrial _________.

A

increases; photosynthesis

47
Q

What happens to the amount of CO2 in the atmosphere during the fall-winter period?

A

It rises because there is little production of oxygen by photosynthesis.

48
Q

What happens to the amount of CO2 in the atmosphere during the spring-summer period?

A

It falls because there is high production of oxygen by photosynthesis.

49
Q

Excess CO2 in the atmosphere can lead to _________ because it prevents some of the sun’s energy from ________ back into _______.

A

climate change; re-radiating; space

50
Q

Carbon is trapped in ______, which is ground that is frozen year-round.

A

permafrost

51
Q

What happens when permafrost begins to melt?

A

Plants trapped in the ice release massive amounts of CO2 into the atmosphere.

52
Q

Nitrogen gas makes up _________ of the atmosphere, but this form of nitrogen is ______ by most living organisms.

A

78%; unusable

53
Q

What are the six reasons nitrogen cycles?

A

1) fixation
2) ammonification
3) nitrification
4) assimilation
5) decomposition
6) denitrification

54
Q

_________ makes amino acids which make _______.

A

Nitrogen; proteins

55
Q

_________ is needed for DNA, RNA, and ATP and is found in the lithosphere, Earth’s crust.

A

Phosphorous

56
Q

Gross primary productivity is higher than net primary productivity. The difference between the two is

A) the amount of energy that producers burn when they metabolize.

B) typically the ratio between the biomass of producers and the biomass of consumers.

C) an important measure of ecosystem productivity.

D) energy that is lost into outer space due to physiological inefficiencies.

E) untapped energy that is stored in plant roots.

A

A) the amount of energy that producers burn when they metabolize.

57
Q

Why are big, fierce animals rare? Most big, fierce animals are tertiary consumers, which implies that

A) typically, they are highly territorial.

B) It’s hard for an ecosystem to support many of them because so much energy is lost at each level of energy exchange.

C) humans have caused most big, fierce animals to become extinct.

D) it takes a long time for big animals to evolve, and the K-T evidence for an ancient meteor strike eliminated dinosaurs and most other big, fierce animals.

E) It’s hard for a big animal to move through dense vegetation.

A

B) It’s hard for an ecosystem to support many of them because so much energy is lost at each level of energy exchange.

58
Q

Which of the following processes transfers the most energy in a forest ecosystem?

A) Photosynthesis

B) Organismal Digestion

C) Excretion

D) Respiration

E) Death

A

A) Photosynthesis

59
Q

Which of these organisms can produce organic matter from inorganic materials?

A) heterotrophs

B) photoautotrophs

C) detritivores

D) chemoautotrophs

E) chemoheterotrophs

A

B) photoautotrophs

D) chemoautotrophs

60
Q

Adding autotroph respiration to net community production yields:

A) Phytosynthetic efficiency

B) Gross primary production

C) Autotroph growth efficiency

D) Net primary production

E) None of the above

A

B) Gross primary production

61
Q

Why does a biomass pyramid for a forest show less biomass at the primary consumer level than a grassland does?

A) Forests contain fewer primary consumers.

B) Secondary consumers eat more primary consumers in forests.

C) Primary production of forests is higher than that of grasslands.

D) Most of the biomass in a forest is tied up in material that is difficult to digest.

E) Both a and b

A

D) Most of the biomass in a forest is tied up in material that is difficult to digest.

62
Q

Which of the following pools of carbon is the largest?

A) CO2 in the atmosphere

B) terrestrial biomass

C) rocks and sediments

D) oceanic biomass

E) CO2 in the ocean

A

C) rocks and sediments

63
Q

Which of the following fluxes of C is the largest?

A) terrestrial photosynthesis

B) fossil fuel combustion

C) respiration

D) land use changes by humans

E) weathering

A

A) terrestrial photosynthesis

64
Q

We are concerned about carbon dioxide increases in our global atmosphere. Imagine that we planted trees over a large area to grow into a forest perhaps the size of Australia. Would this be a good, permanent way to stop or slow the accumulation of carbon dioxide in the atmosphere?

A) No, because plants release carbon dioxide when they do photosynthesis.

B) Yes, because the trees would convert carbon dioxide into wood.

C) Perhaps, but when the trees died and decayed, the carbon dioxide would be returned to the atmosphere.

D) It is unlikely that plants could make much difference in global air concentrations.

E) Yes, because it would show the world we were serious about stopping global warming.

A

C) Perhaps, but when the trees died and decayed, the carbon dioxide would be returned to the atmosphere.

65
Q

What 2 factors contribute to the difference in shape of biomass pyramids in terrestrial and aquatic ecosystems?

A

1) Terrestrial plants invest a great deal of biomass in structural materials

2) In aquatic systems, primary producers can grow much more rapidly than secondary producers

66
Q

How does the amount of energy available change with increasing trophic level in a food web?

A) Energy does not change, only matter.

B) Energy reaches producers and falls to zero for higher trophic levels

C) The energy available decreases by about half with each trophic transfer.

D) The energy available decreases sharply with trophic level in all ecosystems.

E) Energy is conserved and only a small amount of energy is lost through trophic transfers.

A

D) The energy available decreases sharply with trophic level in all ecosystems.

67
Q

What factor(s) is/are the primary drivers of the annual oscillation in carbon dioxide concentration in the atmosphere?

A) CO2 decreases during the Northern hemisphere spring-summer due to terrestrial photosynthesis

B) CO2 increases during the Northern Hemisphere winter due to increased burning of fossil fuels to heat homes and businesses.

C) CO2 increases in the Northern Hemisphere spring as Arctic sea ice melts, releasing trapped CO2

D) CO2 increases during the Northern hemisphere winter due to oceanic respiration

E) CO2 increases during the Northern Hemisphere winter due to terrestrial respiration.

A

A) CO2 decreases during the Northern hemisphere spring-summer due to terrestrial photosynthesis

E) CO2 increases during the Northern Hemisphere winter due to terrestrial respiration.

68
Q

Biological productivity is commonly limited by nitrogen availability, yet large quantities of N2 are present in the atmosphere and dissolved in the ocean. How can this be?

A) N2 is highly reactive and generally consumed by physical processes before organisms can access it

B) N2 can be used by only a few organisms possessing specialized enzymes, so the nitrogen in N2 is unavailable to most organisms.

C) N2 is used by many organisms and resource competition leads to limitation.

D) Although nitrogen fixation introduces biologically available nitrogen to ecosystems, denitrification converts this biologicaly available nitrogen to N2, making it unavailable to most organisms.

E) None of these.

A

B) N2 can be used by only a few organisms possessing specialized enzymes, so the nitrogen in N2 is unavailable to most organisms.

D) Although nitrogen fixation introduces biologically available nitrogen to ecosystems, denitrification converts this biologically available nitrogen to N2, making it unavailable to most organisms.

69
Q

Which of the following fluxes of C is currently the largest?

A) plant respiration

B) fossil fuel combustion

C) respiration by microbes and decomposers

D) absorption of CO2 by the ocean

E) deep sea burial of organic carbon

A

D) absorption of CO2 by the ocean

70
Q

Predator-prey interactions have led to the co-evolution (in the direction indicated) of all of the following except:

A) more cryptic colouration in the predator

B) more cryptic colouration in the prey

C) more showy tails as secondary sexual traits in male birds

D) stronger aposematic colouration in the prey

E) stronger mimicry of a toxic prey by a non-toxic prey species.

A

C) more showy tails as secondary sexual traits in male birds

71
Q

Which of the following statements about the distribution of barnacles in rocky intertidal systems is/are correct?

A) the upper limit of a barnacle’s distribution is generally set by physical factors.

B) the lower limit of a barnacle’s distribution is generally set by biological factors.

C) most barnacle species can survive in a broader zone of the intertidal than they actually occupy as adults.

D) All of the above.

E) None of the above.

A

D) All of the above.

72
Q

Food webs are made up of _______ (3 things).

A

1) food chains
2) producers and consumers
3) trophic interactions

73
Q

Biomass pyramids in the open ocean are inverted in comparison to most terrestrial ecosystems because __________.

A

the producers reproduce so rapidly that a smaller biomass of producers can support a larger biomass of herbivores.

74
Q

What is responsible for the conversion of most organic material into CO2, which can be utilized in primary production?

A

Primary producers

75
Q

How is it that the open ocean supports the highest total net primary productivity of Earth’s ecosystems, yet net primary productivity per square meter is relatively low?

A

Oceans have the greatest total area.

76
Q

For the past 150 years there has been a major new input to the carbon cycle. What is it?

A

Industrialization has resulted in the burning of fossil fuels such as oil and coal, which releases CO2 into the atmosphere.

77
Q

Which of the following statements about the global carbon cycle is/are correct?

A) measurements of atmospheric CO2 concentration have revealed distinct seasonal variations superimposed on a trend of steadily increasing concentration since the Industrial Revolution.

B) Fossil fuel combustion is currently increasing the atmospheric content of CO2 to levels that have never before occurred on Earth.

C) A wide variety of geochemical data show that the CO2 content of the atmosphere was constant for many millions of years before the beginning of the Industrial Revolution brought widespread combustion of fossil fuels.

D) All of the above.

E) None of the above.

A

A) measurements of atmospheric CO2 concentration have revealed distinct seasonal variations superimposed on a trend of steadily increasing concentration since the Industrial Revolution.

78
Q

Why are aquatic biomass pyramids inverted?

A

Aquatic primary producers have a high reproduction rate and shorter lifespan (due to consumption by predators), so there is less biomass at any given moment compared to organisms in higher trophic levels.