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ecology > chapter 20 > Flashcards

chapter 20 Flashcards

1
Q

provides energy to the ecosystem.

A

Primary productivity

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2
Q

The movement of energy depends on

A

the efficiency of energy flow.

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3
Q

Most energy that moves through ecosystems originates as

A

solar energy that powers photosynthesis.

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4
Q

Where sunlight is not available (e.g., deep ocean thermal vents), producers rely on

A

on chemosynthesis as their source of energy.

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5
Q

Producers use energy for

A

respiration, growth, and reproduction.

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6
Q

the rate at which solar or chemical energy is captured and converted into chemical bonds by photosynthesis or chemosynthesis.

A

Primary productivity

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7
Q

The difference between gross primary productivity (GPP) & NPP (Net PP) is due to

A

the energy lost to respiration.

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8
Q

the biomass of producers present in a given area of an ecosystem at a particular moment in time

A

Standing crop

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9
Q

the rate at which energy is captured and assimilated by producers in an area.

A

Gross primary productivity (GPP):

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10
Q

the rate of energy that is assimilated by producers and converted into producer biomass in an area; includes all energy that is not respired:

A

Net primary productivity (NPP

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11
Q

net primary productivity equation

A

NPP = GPP - Respiration

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12
Q

gross primary productivity equation

A

GPP = NPP + Respiration

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13
Q

respiration equation

A

Respiration = GPP - NPP

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14
Q

is photosynthesis an efficient process

A

no

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15
Q

can be measured as the change in producer biomass over time

A

NPP

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16
Q

Substantial amounts of herbivory or tissue mortality will lead to

A

an underestimation of NPP.

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17
Q

Since producers take up CO2 during photosynthesis and produce CO2 during respiration

A

we can measure NPP by recording the rate of CO2 exchange from the leaf

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18
Q

what happens When a leaf is concealed in the dark

A

only CO2 respiration occurs.

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19
Q

Other techniques used to measure CO2 uptake and release

A
  • place a leaf into a sealed container with added CO2 that contains trace amounts of a rare carbon isotope
  • researchers measure CO2 uptake and release by using towers that sample CO2 concentrations at different heights above the ground.
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20
Q

measuring CO2 does not provide a good estimate of NPP because CO2 is rapidly converted into bicarbonate ions in what systems?

A

aquatic systems

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21
Q

Since producers release O2 during photosynthesis and take up O2 during respiration

A

we can estimate NPP and GPP by measuring changes in concentrations of O2.

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22
Q

In a bottle exposed to light, the net increase in O2 is the combined result of photosynthesis and respiration by

A

algae (NPP).

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23
Q

In a dark bottle, the decrease in O2 is a result of

A

algal respiration.

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24
Q

a technique that allows measurement of conditions on Earth from a distant location, typically using satellites or airplanes that take photographs of large areas of the globe.

A

Remote sensing

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25
Q

high absorption of blue and red light, and high reflectance of green light indicate

A

ecosystems with high standing crops.

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26
Q

the portion of consumed energy that is excreted or regurgitated.

A

Egested energy

27
Q

the portion of energy that a consumer digests and absorbs; analogous to GPP for producers.

A

Assimilated energy

28
Q

the portion of assimilated energy a consumer uses for respiration

A

Respired energy

29
Q

the rate of consumer biomass accumulation in a given area

A

Net secondary productivity

30
Q

Net secondary productivity depends on

A

primary productivity for energy

31
Q

increases in NPP are positively correlated with

A

increases in net secondary productivity.

32
Q

At higher latitudes, productivity is limited by

A

shorter periods of sunlight and lower temperatures

33
Q

In deserts, NPP is constrained by

A

lack of precipitation.

34
Q

Tropical areas have high NPP due to

A

intense sunlight, warm temperatures, abundant precipitation, and rapidly recycled nutrients.

35
Q

Ecosystems that receive more than 3 m of precipitation experience a decline in NPP because

A

nutrients leach from the soil.

36
Q

Rates of decomposition are reduced in

A

waterlogged soils.

37
Q

Grasslands, forests, and tundra habitats all experienced increased NPP when

A

nitrogen and phosphorus were added.

38
Q

In addition to temperature, precipitation, and nutrients, aquatic ecosystems are also limited by

A

light.

39
Q

Within aquatic ecosystems that have similar temperatures and light levels

A

NPP is largely limited by nutrients

40
Q

Diatoms are often limited by

A

by silicon and iron

41
Q

chart composed of stacked rectangles representing the amount of energy (i.e., pyramid of energy) or biomass (i.e., pyramid of biomass) in each trophic group.

A

Trophic pyramid

42
Q

and only small amounts of terrestrial plant material are consumed in what systems

A

terrestrial systems

43
Q

most producers are tiny algae that rapidly reproduce and are quickly consumed in what ecosystems

A

aquatic ecosystems

44
Q

creates an inverted biomass pyramid.

A

standing crop of algae is much smaller than that of consumers

45
Q

the percentage of energy or biomass in a trophic level that is consumed by the next higher trophic level

A

Consumption efficiency

46
Q

the percentage of consumed energy that is assimilated (i.e., material that is not egested, such as bones).

A

Assimilation efficiency

47
Q

primary consumers tend to have lower efficiencies than secondary consumers

A

because prey tissues are more digestible than plant tissues.

48
Q

the percentage of assimilated energy that is used for growth and reproduction; the percentage of assimilated energy that remains after respiration.

A

Net production efficiency

49
Q

net production efficiency can be as low as 1%.for what type of animals

A

active homeothermic animals

50
Q

active homeothermic animals spend energy to

A

maintain body temperature, move, circulate blood, and osmoregulate

51
Q

net production efficiency can be as high as 75%.

A

For sedentary poikilothermic animals

52
Q

the percentage of net production from one trophic level compared to the next lower trophic level.

A

Ecological efficiency (food chain efficiency):

53
Q

the percentage of net production from one trophic level compared to the next lower trophic level.

A

Ecological efficiency (food chain efficiency):

54
Q

ecological efficiency is usually low, ranging from

A

5% to 20%;

55
Q

10% is used as a rule of thumb for

A

ecological efficiency

56
Q

Low ecological efficiencies make it difficult to have long food chains because

A

there is little energy to support higher trophic levels

57
Q

how many trophic levels fo aquatic ecosystems typically have

A

5

58
Q

how many trophic levels do terrestrial ecosystems usually have

A

3-4

59
Q

terrestrial plants are not easily consumed because

A

they contain defense compounds

60
Q

aquatic algae is easily consumed because

A

they are small and have no defenses

61
Q

the length of time that energy spends in a given trophic level; the longer the residence time, the greater the accumulation of energy in that trophic level

A

Energy residence time

62
Q

the length of time that biomass spends in a given trophic level.

A

Biomass residence time

63
Q

Average residence times for primary producers range from

A

more than 20 years in forests to less than 20 days in aquatic ecosystems.

64
Q

the study of the balance of nutrients in ecological interactions, such as between an herbivore and a plant.

A

Ecological stoichiometry

ecology (9 decks)

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