Test 3

Question 1

“… the whole (environment) system including the whole complex of physical factors together with the organism-complex (i.e. community)” is Sir Arthur Tansley’s definition of the:

Answer 1

Ecosystem

Question 2

Food webs can be arranged into ____ levels base in whether organisms obtain their energy through photosynthesis, from eating dead organic matter, from eating plants, or from eating animals.

Answer 2

Trophic

Question 3

Ecosystems have 2 major food chains: ____ and _____.

Answer 3

Grazing and detrital

Question 4

When a predator enhances the success of inferior competitors by suppressing a superior competitor, the interaction is called:

Answer 4

Keystone predation

Question 5

When populations at a given trophic level are controlled by populations in the trophic level above them, are said to be under _____ control.

Answer 5

Top-down

Question 6

An ecologist studying productivity in an annual grassland measures gross primary productivity as 1000 kcal/m2/year and autotrophic respiration as 100 kcal/m2/year. Based on these calculations, the net primary productivity is:

Answer 6

900 kcal/m2/year

Question 7

Higher trophic levels in a food chain contain _____ energy compared to lower trophic levels.

Answer 7

Less

Question 8

Assimilation by the herbivore trophic level is equal to ____ kcal/year in the food web illustrated by figure 1.

Answer 8

1000

Question 9

Respiration by the herbivore trophic level is equal to ____ kcal/year in the food web illustrated in Figure 1.

Answer 9

970

Question 10

Production efficiency by the herbivore trophic level is equal to ____ in the food web illustrated by figure 1.

Answer 10

3%

Question 11

Production of the predator trophic level is equal to ___ kcal/year in the food web illustrated by figure 1.

Answer 11

0.08

Question 12

Using the data presented in figure 1, which of the following has the greatest value?

Answer 12

The trophic efficiency of the gazelle trophic level

Question 13

The “world is green” hypothesis of Hairston, Smith and Slobodkin is an example of _____ of the plant community by predators.

Answer 13

Top-down control

Question 14

The feeding strategy with the highest assimilation efficiency is:

Answer 14

Carnivore

Question 15

All other things being equal, production efficiency is typically highest among:

Answer 15

Poikilotherms

Question 16

Aquatic ecosystems dominated by phytoplankton typically support _____ rates of herbivory than those in which vascular plants dominate.

Answer 16

Higher

Question 17

In terrestrial ecosystems, the ____ food chain is the major pathway of energy flow.

Answer 17

Detrital

Question 18

In which of the following ecosystems does the grazing food chain typically have the greatest consumption efficiency?

Answer 18

Marine ecosystems

Question 19

Under what conditions may one expect to encounter “inverted trophic pyramids” where consumer biomass exceeds producer biomass?

Answer 19

In ecosystems where turnover of phytoplankton exceeds turnover of zooplankton

Question 20

In a food web where a decrease in primary productivity is observed following the removal of predators, the resulting trophic interactions might be considered an example of:

Answer 20

Top-down control

Question 21

_______ have a disproportionate impact on the community structure and ecosystem functioning relative to their abundance and/or biomass.

Answer 21

Keystone species

Question 22

The rate of energy acquisition by plants after accounting for autotrophic respiration is:

Answer 22

Net primary productivity

Question 23

Secondary production is most directly limited primarily by:

Answer 23

Primary production

Question 24

The rate of energy acquisition by plants after accounting for autotrophic and heterotrophic respiration is:

Answer 24

Net ecosystem productivity

Question 25

By utilizing the process of ____, plants avoid losing all of the nutrients in sensing tissues.

Answer 25

Re-absorption/translocation

Question 26

Which of the following breaks down the slowest during decomposition?

Answer 26

Lignin

Question 27

Which of the following is an important process involved in decomposition?

Answer 27

Leaching, Fragmentation, Mineralization

Question 28

Which of the following is not a component of plant tissue?

Answer 28

Chitin

Question 29

Which of the following conditions is conductive to a high rate of decomposition?

Answer 29

High temperatures, High moisture

Question 30

In figure 2, ____ occurs at stage A.

Answer 30

Leaching

Question 31

In figure 2, _____ occurs at stage B.

Answer 31

Net N Immobilization (immobilization > mineralization)

Question 32

In figure 2, _____ occurs at stage C.

Answer 32

Net N mineralization (immobilization < mineralization)

Question 33

Decomposition:

Answer 33

Exhibits negative exponential kinetics, Is a biotic and physical process where C and nutrients are released from organic matter

Question 34

Which of the following organisms are not important agents of decomposition?

Answer 34

Plants

Question 35

The process of conversion of nutrients from an organic form into an inorganic form that plants can use is called:

Answer 35

Mineralization

Question 36

Which of the following elements is typically the most limiting nutrient to primary production in terrestrial environments?

Answer 36

Nitrogen

Question 37

In lakes nutrients and oxygen are seasonally vertically stratified by: ___.

Answer 37

Temperature

Question 38

In aquatic ecosystems production and decomposition are often ______.

Answer 38

Spatially decoupled

Question 39

Which of the following elements is most closely linked to the energy cycle in ecosystems?

Answer 39

Carbon

Question 40

Soil organic matter is:

Answer 40

Made up of microscopic organisms, recently dead biological material and residues of decomposing plant and animal matter, Comprised of detritus and humus, The largest pool of terrestrial organic carbon

Question 41

As decomposition proceeds, which molecule is lost to the atmosphere?

Answer 41

CO2

Question 42

The global nitrogen cycle is dominated by the ____ reservoir.

Answer 42

Atmosphere

Question 43

Nitrogen is a limiting nutrient to primary production in terrestrial ecosystems because:

Answer 43

Nitrogen is an important constituent of amino acids, Some forms of nitrogen are highly mobile in terrestrial ecosystems and easily lost, Nitrogen may be tightly bound in soil humus fractions for hundreds of years

Question 44

The rate of carbon cycling between the atmosphere and the biosphere is determined by:

Answer 44

Primary production, Decomposition

Question 45

Nitrogen fixation is:

Answer 45

An energy intensive biochemical pathway, A process facilitated by bacteria

Question 46

The primary source of sulfur to the atmosphere contributed by human activity is:

Answer 46

Smokestack emissions from coal burning

Question 47

Excess nitrogen in the environment may contribute to:

Answer 47

Acid rain, Nitrate contamination of ground and surface water Agriculture run-off, Eutrophication

Question 48

Which of the following nutrients has a cycle that does NOT contain s significant atmosphere phase?

Answer 48

Phosphorous

Question 49

Atmospheric CO2 levels increased from 280 to a little over ____ ppm since the Industrial Revolution.

Answer 49

400 ppm