chapter 20

Question 1

provides energy to the ecosystem.

Answer 1

Primary productivity

Question 2

The movement of energy depends on

Answer 2

the efficiency of energy flow.

Question 3

Most energy that moves through ecosystems originates as

Answer 3

solar energy that powers photosynthesis.

Question 4

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

Answer 4

on chemosynthesis as their source of energy.

Question 5

Producers use energy for

Answer 5

respiration, growth, and reproduction.

Question 6

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

Answer 6

Primary productivity

Question 7

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

Answer 7

the energy lost to respiration.

Question 8

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

Answer 8

Standing crop

Question 9

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

Answer 9

Gross primary productivity (GPP):

Question 10

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

Answer 10

Net primary productivity (NPP

Question 11

net primary productivity equation

Answer 11

NPP = GPP - Respiration

Question 12

gross primary productivity equation

Answer 12

GPP = NPP + Respiration

Question 13

respiration equation

Answer 13

Respiration = GPP - NPP

Question 14

is photosynthesis an efficient process

Answer 14

no

Question 15

can be measured as the change in producer biomass over time

Answer 15

NPP

Question 16

Substantial amounts of herbivory or tissue mortality will lead to

Answer 16

an underestimation of NPP.

Question 17

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

Answer 17

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

Question 18

what happens When a leaf is concealed in the dark

Answer 18

only CO2 respiration occurs.

Question 19

Other techniques used to measure CO2 uptake and release

Answer 19

• 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.

Question 20

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

Answer 20

aquatic systems

Question 21

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

Answer 21

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

Question 22

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

Answer 22

algae (NPP).

Question 23

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

Answer 23

algal respiration.

Question 24

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.

Answer 24

Remote sensing

Question 25

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

Answer 25

ecosystems with high standing crops.

Question 26

the portion of consumed energy that is excreted or regurgitated.

Answer 26

Egested energy

Question 27

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

Answer 27

Assimilated energy

Question 28

the portion of assimilated energy a consumer uses for respiration

Answer 28

Respired energy

Question 29

the rate of consumer biomass accumulation in a given area

Answer 29

Net secondary productivity

Question 30

Net secondary productivity depends on

Answer 30

primary productivity for energy

Question 31

increases in NPP are positively correlated with

Answer 31

increases in net secondary productivity.

Question 32

At higher latitudes, productivity is limited by

Answer 32

shorter periods of sunlight and lower temperatures

Question 33

In deserts, NPP is constrained by

Answer 33

lack of precipitation.

Question 34

Tropical areas have high NPP due to

Answer 34

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

Question 35

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

Answer 35

nutrients leach from the soil.

Question 36

Rates of decomposition are reduced in

Answer 36

waterlogged soils.

Question 37

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

Answer 37

nitrogen and phosphorus were added.

Question 38

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

Answer 38

light.

Question 39

Within aquatic ecosystems that have similar temperatures and light levels

Answer 39

NPP is largely limited by nutrients

Question 40

Diatoms are often limited by

Answer 40

by silicon and iron

Question 41

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.

Answer 41

Trophic pyramid

Question 42

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

Answer 42

terrestrial systems

Question 43

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

Answer 43

aquatic ecosystems

Question 44

creates an inverted biomass pyramid.

Answer 44

standing crop of algae is much smaller than that of consumers

Question 45

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

Answer 45

Consumption efficiency

Question 46

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

Answer 46

Assimilation efficiency

Question 47

primary consumers tend to have lower efficiencies than secondary consumers

Answer 47

because prey tissues are more digestible than plant tissues.

Question 48

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

Answer 48

Net production efficiency

Question 49

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

Answer 49

active homeothermic animals

Question 50

active homeothermic animals spend energy to

Answer 50

maintain body temperature, move, circulate blood, and osmoregulate

Question 51

net production efficiency can be as high as 75%.

Answer 51

For sedentary poikilothermic animals

Question 52

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

Answer 52

Ecological efficiency (food chain efficiency):

Question 53

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

Answer 53

Ecological efficiency (food chain efficiency):

Question 54

ecological efficiency is usually low, ranging from

Answer 54

5% to 20%;

Question 55

10% is used as a rule of thumb for

Answer 55

ecological efficiency

Question 56

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

Answer 56

there is little energy to support higher trophic levels

Question 57

how many trophic levels fo aquatic ecosystems typically have

Answer 57

5

Question 58

how many trophic levels do terrestrial ecosystems usually have

Answer 58

3-4

Question 59

terrestrial plants are not easily consumed because

Answer 59

they contain defense compounds

Question 60

aquatic algae is easily consumed because

Answer 60

they are small and have no defenses

Question 61

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

Answer 61

Energy residence time

Question 62

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

Answer 62

Biomass residence time

Question 63

Average residence times for primary producers range from

Answer 63

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

Question 64

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

Answer 64

Ecological stoichiometry