Deck 20: Movement of Energy in Ecosystems

Question 1

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.

Answer 1

C

Question 2

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

Answer 2

D

Question 3

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

Answer 3

B

Question 4

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

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

Question 5

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 6

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 7

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 8

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

Question 9

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

Question 10

Net primary productivity is calculated as

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

Question 11

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

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

Question 12

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

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

Question 13

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 14

Standing crop is determined by _____ productivity.

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

Question 15

Why have nonnative 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 16

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

Question 17

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 18

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

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

Question 19

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 20

Energy that an organism uses to add to its biomass is

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

Question 21

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

A) estuary
B) coral reef
C) stream
D) coastal ocean

Question 22

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

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

Question 23

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

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

Question 24

Aquatic NPP is primarily limited by

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

Question 25

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

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

Question 26

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

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

Question 27

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 28

NPP varies with _____ around the world.

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

Question 29

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

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

Question 30

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 31

Silicon is used primarily by

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

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 metre squared per second?

Question 33

What are the major drivers of NPP?

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

Question 34

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 35

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 36

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 37

(Figure 20.8) 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 metres of precipitation, after which productivity declines. Why does this decline occur?

Question 38

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

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

Question 39

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 40

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 41

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 42

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 43

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 44

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 45

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 46

Net production energy divided by assimilation energy is _____ efficiency.

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

Question 47

The lowest level in marine trophic pyramids is

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

Question 48

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 49

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 50

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 lifespan of producers is very long compared to that of consumers.
D) consumers do not rapidly consume producers.

Question 51

Aquatic ecosystems typically have ?????_____ trophic levels, while terrestrial ecosystems typically have _____ trophic levels.
A) four; five

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

Question 52

Food chain efficiency is the percentage of _____ from one trophic level compared with the next_____ trophic level.
A) consumed energy; higher

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

Question 53

A trophic level has a biomass residence time of 5 years and net productivity of 3 kg/m²/y. What is the biomass in the trophic level?

A) 1.7 kg/m2
B) 15 kg/m2
C) 0.6 kg/m2
D) 2 kg/m2

Question 54

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 55

Ecological efficiency is also called _____ efficiency.

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

Question 56

The _____ the residence time, the _____ amount of biomass in the trophic level.

A) shorter
B) longer
C) longer
D) shorter

Question 57

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 58

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.