Deck 20: Movement of Energy in Ecosystems　

Question 1

What proportion of solar radiation captured by photosynthesis is used for plant growth and reproduction?

A) 60 percent
B) 80 percent
C) 50 percent
D) 40 percent

Answer 1

D

Question 2

Why can plants use only a small portion of the light energy that strikes the surface of a leaf?

Answer 2

not answered

Question 3

Terrestrial secondary productivity is _____ correlated with primary productivity, and aquatic secondary productivity is _____ correlated with primary productivity.

A) positively; positively
B) positively; negatively
C) negatively; negatively
D) negatively; positively

Answer 3

A

Question 4

Why have non-native earthworms caused a decline in salamander populations in North America?

A) Earthworms are predators of newly hatched salamanders.
B) Earthworms caused reductions in insects that salamanders eat.
C) Earthworms disturb soil, which makes it less hospitable to salamanders.
D) Earthworms outcompete salamanders for soil nutrients.

Question 5

Which of the following is NOT used to measure primary production?

A) uptake and release of O₂
B) net movement of ¹⁴C
C) release of CO₂
D) changes in standing crop

Question 6

What is the source of most energy that moves through ecosystems?

A) oceans
B) soil nutrients
C) the Sun
D) Earth's core

Question 7

The rate at which solar or chemical energy is captured and converted to chemical bonds by photosynthesis or chemosynthesis is called

A) secondary productivity.
B) net primary productivity.
C) gross primary productivity.
D) primary productivity

Question 8

Measuring the change in biomass from the beginning to the end of the growing season gives an estimate of

A) herbivory.
B) standing crop.
C) gross primary productivity.
D) net primary productivity.

Question 9

Which technique allows measurement of conditions on Earth from a distant location?

A) remote sensing
B) remote monitoring
C) satellite sensing
D) satellite monitoring

Question 10

Standing crop is determined by _____ productivity.

A) net primary
B) gross primary
C) net secondary
D) gross secondary

Question 11

The rate of consumer biomass accumulation in a given area is called _____ productivity.

A) gross secondary
B) net secondary
C) gross primary
D) net primary

Question 12

Energy that an organism uses to add to its biomass is

A) egested.
B) respired.
C) assimilated.
D) secondary.

Question 13

Which of the following units is commonly used to express GPP?

A) kJ/m²/y
B) kPa/m²/y
C) kg/m²/y
D) kmol/m²/y

Question 14

Which is the portion of energy that an organism uses to maintain its body temperature?

A) primary
B) secondary
C) egested
D) respired

Question 15

Net primary productivity is calculated as

A) GPP ÷ respiration.
B) GPP × respiration.
C) respiration - GPP.
D) GPP - respiration.

Question 16

The biomass of producers in a given area of an ecosystem at a particular moment is called

A) net primary production.
B) ecosystem mass.
C) the standing crop.
D) the standing harvest.

Question 17

What percentage of solar energy is captured by plants for photosynthesis?

A) 50 percent
B) 1 percent
C) 99 percent
D) 25 percent

Question 18

Terrestrial primary productivity can be quantified by measuring the uptake and release of

A) carbon dioxide.
B) water vapor.
C) nitrate.
D) methane.

Question 19

When an animal eats fruit with hard seeds that cannot be digested and are excreted whole as a waste product, the seeds constitute _____ energy.

A) assimilated
B) egested
C) respired
D) kinetic

Question 20

Which of the following factors is NOT used for quantifying primary productivity over time?

A) the change in consumer biomass
B) the change in producer biomass
C) the movement of carbon dioxide
D) the movement of oxygen

Question 21

Experiments on how soil fertility limits terrestrial NPP demonstrate that _____ constrain(s) NPP.

A) nitrogen
B) phosphorus
C) nitrogen and phosphorus
D) micronutrients

Question 22

Iron is lost from oceans when it combines with _____ and precipitates.

A) nitrogen
B) silicon
C) phosphorus
D) carbon

Question 23

Aquatic ecosystems can be limited by silicon because

A) there are few silicon organisms in the upper waters.
B) many organisms compete for the silicon.
C) silicon sinks slower than nitrogen or phosphorus.
D) silicon sinks faster than nitrogen or phosphorus.

Question 24

Which of the following is NOT a low-productivity aquatic ecosystem?

A) open ocean
B) coral reef
C) forest stream
D) deep ocean

Question 25

Aquatic NPP is primarily limited by

A) fertility.
B) light.
C) temperature.
D) salinity.

Question 26

Which of the following ecosystems has the highest levels of primary productivity?

A) coral reef
B) swamp
C) lake
D) salt marsh

Question 27

What are the major drivers of NPP?

A) fertility and precipitation
B) temperature and pH
C) temperature and precipitation
D) fertility and temperature

Question 28

Which of the following is NOT a high-productivity aquatic ecosystem?

A) estuary
B) coral reef
C) salt marsh
D) open ocean

Question 29

Terrestrial NPP is greatest in _____ ecosystems, and aquatic NPP is greatest in _____ ecosystems.

A) tropical; coastal
B) tropical; open-water
C) polar; tropical
D) tropical; tropical

Question 30

Which of the following ecosystems has the lowest levels of primary productivity?

A) desert scrub
B) temperate grassland
C) savanna
D) tundra

Question 31

Between latitudes of 30° N and 30° S, NPP is primarily constrained by

A) temperature.
B) fertility.
C) pH.
D) precipitation.

Question 32

A terrestrial ecosystem has an NPP of 850 g C/m²/y and respiration of 1.25 kg C/m²/y. What is the ecosystem GPP in kilograms per meter squared per second?

Question 33

What nutrient fertilization has been discussed as a way to counteract global warming? How would the nutrient(s) affect global warming, and what are the drawbacks, if any?

Question 34

In addition to nitrogen and phosphorus, what nutrients can limit productivity in the open ocean?

A) silicon and magnesium
B) silicon and iron
C) manganese and iron
D) molybdenum and manganese

Question 35

NPP varies with _____ around the world.

A) elevation
B) soil type
C) longitude
D) latitude

Question 36

Compilation of data from many experiments on nutrients and NPP in marine ecosystems shows that ecosystems with hard bottoms are generally limited by _____, while soft-bottomed ecosystems are generally limited by _____.

A) nitrogen; phosphorus
B) nitrogen; nitrogen and phosphorus
C) phosphorus; nitrogen
D) phosphorus; nitrogen and phosphorus

Question 37

(Figure 20.9) The figure shows that as mean annual temperature increases, net primary productivity also increases. Net primary productivity increases with mean annual precipitation until approximately 3 meters of precipitation, after which productivity declines. Why does this decline occur?

Question 38

What is the primary reason that estuaries and coral reefs are so productive?

A) high temperatures due to tropical location
B) low levels of herbivory
C) high light levels due to shallow waters
D) high nutrient levels from runoff

Question 39

In fertilization experiments in a lake in Ontario, which of the following nutrients were shown to have the greatest limitation on productivity?

A) nitrogen
B) carbon
C) phosphorus
D) All three nutrients equally limited productivity.

Question 40

Silicon is used primarily by

A) zooxanthellae.
B) zooplankton.
C) diatoms.
D) algae.

Question 41

What accounts for the pyramid shape of the diagram that represents energy in trophic groups in an ecosystem?

A) Energy produced by consumers is greater than energy stored by producers.
B) Energy stored by consumers is greater than energy stored by producers.
C) Energy is gained as it moves from one trophic level to the next.
D) Energy is lost as it moves from one trophic level to the next.

Question 42

The study of the balance of nutrients in ecological interactions is called

A) ecosystem ecology.
B) ecological stoichiometry.
C) chemical ecology.
D) stoichiometric biochemistry.

Question 43

Energy (J)
Terrestrial Ecosystem
Aquatic Ecosystem
Net production available in lower trophic level
1,500
1,500
Consumed energy
375
826
Assimilated energy
260
550
Net production energy
84
210
Calculate in joules the four types of ecological efficiencies for the terrestrial and aquatic ecosystems from the table. Which ecosystem is more ecologically efficient?

Question 44

Assimilation energy is the percentage of consumed energy that is

A) used for reproduction.
B) digested and absorbed.
C) used for growth.
D) consumed by the next higher trophic level.

Question 45

The average energy residence time is calculated as

A) energy in a trophic level times net productivity.
B) net productivity times energy in a trophic level.
C) energy in a trophic level divided by net productivity.
D) net productivity divided by energy present in a trophic level.

Question 46

The percentage of energy or biomass in a trophic level that is consumed by the next higher trophic level is called _____ efficiency.

A) consumption
B) predation
C) assimilation
D) net production

Question 47

Consumption efficiency is calculated as

A) consumed energy times net production energy of the next lower trophic level.
B) net production energy of the next lower trophic level divided by consumed energy.
C) consumed energy divided by net production energy of the next higher trophic level.
D) consumed energy divided by net production energy of the next lower trophic level.

Question 48

As a rule of thumb, ecologists use _____ as a value for food chain efficiency.

A) 10 percent
B) 25 percent
C) 15 percent
D) 20 percent

Question 49

The lowest level in marine trophic pyramids is

A) phytoplankton.
B) zooplankton.
C) pelagic fish.
D) periplankton.

Question 50

Food chain efficiency is the percentage of _____ from one trophic level compared to the next _____ trophic level.

A) net production; higher
B) net production; lower
C) consumed energy; higher
D) consumed energy; lower

Question 51

Aquatic ecosystems typically have _____ trophic levels, while terrestrial ecosystems typically have _____ trophic levels.

A) two; three
B) four; five
C) three or four; six
D) five; three or four

Question 52

Net production energy divided by assimilation energy is _____ efficiency.

A) consumption
B) assimilation
C) net assimilation
D) net production

Question 53

Red abalone (Haliotis rufescens) has a ratio of nitrogen to phosphorus of 45:1. The abalone consumes giant kelp (Macrocystis pyrifera), which has a ratio of nitrogen to phosphorus of 20:1. Would you expect this trophic level to have a high or low ecological efficiency? Why?

Question 54

Why when measuring primary productivity is O₂ uptake perhaps a more reliable technique than CO₂ uptake?

Question 55

What is at the top level of a four-level, terrestrial trophic pyramid?

A) quaternary consumers
B) tertiary consumers
C) secondary consumers
D) producers

Question 56

Biomass residence time is the length of time that

A) biomass takes to move through the food chain.
B) energy takes to move through the food chain.
C) energy spends in a given trophic level.
D) biomass spends in a given trophic level.

Question 57

In which ecosystem does leaf litter have the shortest residence time?

A) humid tropical forest
B) temperate forest
C) dry tropical forest
D) boreal forest

Question 58

Differentiate between gross primary productivity (GPP) and net primary productivity (NPP).

Question 59

Ecological efficiency is also called _____ efficiency.

A) trophic pyramid
B) food chain
C) assimilation
D) net production

Question 60

In aquatic ecosystems, trophic pyramids of biomass are inverted because

A) most biomass is found in the producers.
B) the standing biomass of algae is lower than the standing biomass of consumers.
C) the life span of producers is very long compared to that of consumers.
D) consumers do not rapidly consume producers.

Question 61

In terms of NPP (net primary productivity), the most productive terrestrial systems are found in _____, while the most productive aquatic systems are found in _____.

A) temperate forests; open ocean
B) boreal forest; salt marshes
C) savannas; coral reefs
D) tropical forests; freshwater marshes

Question 62

Researchers have found that whales consume approximately _____ of the ocean's NPP (net primary productivity).

A) 88 percent
B) 50 percent
C) 12 percent
D) 3 percent

Question 63

The decline of red-backed salamanders in some regions of eastern North America appears to be related to

A) an increase in non-native earthworms.
B) an increase in predatory songbirds like the ovenbird.
C) a decrease in forest productivity.
D) an increase in forest nutrient cycling by bacteria and fungi.

Question 64

When looking at net production efficiencies, we would likely

A) see homeotherms having a higher efficiency than poikilotherms.
B) see homeotherms having a lower efficiency than poikilotherms.
C) see homeotherms and poikilotherms having the same net production efficiencies.
D) not be able to determine since net production efficiencies cannot be quantified for poikilotherms.

Question 65

Using remote sensing, an ecosystem with high absorption of blue and red wavelengths and high reflectance of green reflectance would likely be found

A) in the polar regions.
B) in the tropical rainforest.
C) in the desert.
D) in the open ocean.

Question 66

The 10 percent ecological efficiency rule of thumb has implications for humans in what way?

A) The 10 percent rule can instruct humans as to which systems need the most protection.
B) Understanding the 10 percent rule might protect species from extinction.
C) Recognizing the 10 percent efficiency rule may provide insight into future human diets on an increasingly populated planet.
D) The 10 percent ecological efficiency rule points to the open ocean as a means to increase worldwide food production.

Question 67

Why do aquatic systems tend to have more trophic levels than terrestrial systems?

Question 68

What term describes the total mass of trees, shrubs, herbaceous plants, and grasses present in a given forest on a given day?

A) NPP, or net primary productivity
B) GPP, or gross primary productivity
C) primary productivity
D) standing crop