Chapter 55

Question 1

Ecosystem

Answer 1

All the organisms living in a community, as well as the abiotic factors with which they interact

Question 2

Ecosystems range from a _, such as the space under a fallen log, to a large area, such as a lake or island.

Answer 2

Microcosm

Question 3

Regardless of an ecosystem’s size, its dynamics involve two main processes: _ and _.

Answer 3

Energy flow; chemical cycling

Question 4

Energy flows _ ecosystems, while matter cycles _ ecosystem.

Answer 4

Through; within

Question 5

Laws of physics and chemistry apply to ecosystems, particularly _.

Answer 5

Energy flow

Question 6

The first law of thermodynamics states that _ cannot be created or destroyed; only transformed.

Answer 6

Energy

Question 7

Ecologists study the _ of energy and matter within ecosystems.

Answer 7

Transformations

Question 8

Energy enters an ecosystem as solar radiation, is _, and is released from organisms as heat.

Answer 8

Conserved

Question 9

Autotrophs build molecules themselves using _ as an energy source.

Answer 9

Photosynthesis

Question 10

Heterotrophs depend on the _ of other organisms.

Answer 10

Biosynthetic output

Question 11

Energy and nutrients pass from _ (autotrophs) to primary consumers (herbivores) to secondary consumers (carnivores) to tertiary consumers (carnivores that feed on other carnivores).

Answer 11

Primary producers

Question 12

In most ecosystems, _ is the amount of light energy converted to chemical energy by autotrophs during a given time period.

Answer 12

Primary production

Question 13

Only a small fraction of _ actually strikes photosynthetic organisms, and even less is of a usable wavelength.

Answer 13

Solar energy

Question 14

Energy flows into the biological world from the _.

Answer 14

Sun

Question 15

_, _, and _ are among the most productive ecosystems per unit area.

Answer 15

Tropical rain forests; estuaries; coral reefs

Question 16

_ ecosystems are relatively unproductive per unit area but contribute much to global net primary production because of their size.

Answer 16

Marine

Question 17

In marine and freshwater ecosystems, both _ and _ control primary production.

Answer 17

Light; nutrients

Question 18

_ of light penetration affects primary production of an ocean or lake.

Answer 18

Depth

Question 19

More than light, _ (like nitrogen and phosphorus) limit primary production in most oceans and lakes.

Answer 19

Nutrients

Question 20

In terrestrial ecosystems, _ and moisture affect primary production on a large scale.

Answer 20

Temperature

Question 21

Primary production increases with _.

Answer 21

Moisture

Question 22

Some plants form mutualistic relationships with nitrogen-fixing _.

Answer 22

Bacteria

Question 23

Many plants form mutualistic relationships with mycorrhizal _; these supply plants with phosphorus and other limiting elements.

Answer 23

Fungi

Question 24

Secondary production (of an ecosystem)

Answer 24

The amount of chemical energy in food converted to new biomass during a given period of time

Question 25

An organism’s _ is the fraction of energy stored in food that is not used for respiration.

Answer 25

Production efficiency

Question 26

Birds and mammals have production efficiencies in the range of 1-3% because of the high cost of _.

Answer 26

Endothermy

Question 27

Fishes have production efficiencies of around _%.

Answer 27

10

Question 28

Insects and microorganisms have efficiencies of _% or more.

Answer 28

40

Question 29

When a caterpillar feeds on a leaf, only about _ of the leaf’s energy is used for secondary production.

Answer 29

One-sixth

Question 30

Approximately 0.1% of chemical energy fixed by photosynthesis reaches a _.

Answer 30

Tertiary consumer

Question 31

A _ of net production represents the loss of energy with each transfer in a food chain.

Answer 31

Pyramid

Question 32

Life depends on recycling chemical elements such as gaseous…

Answer 32

…carbon, oxygen, sulfur, and nitrogen.

Question 33

Carbon, oxygen, sulfur, and nitrogen cycle _ in terrestrial systems but more _ when dissolved in aquatic systems.

Answer 33

Locally; broadly

Question 34

Nutrient cycles in ecosystems involve biotic and abiotic components and are often called _.

Answer 34

Biogeochemical cycles

Question 35

Water is essential to all organisms; _ water is the primary physical phase in which water is used.

Answer 35

Liquid

Question 36

The _ contain 97% of the biosphere’s water; 2% is in _ and _, and 1% is in _, _, and _.

Answer 36

Oceans; glaciers; polar ice caps; lakes, rivers, groundwater

Question 37

Carbon-based _ molecules are essential to all organisms.

Answer 37

Organic

Question 38

CO2 is taken up and released through photosynthesis and _; additionally, volcanoes and the burning of fossil fuels contribute CO2 to the atmosphere.

Answer 38

Respiration

Question 39

Photosynthetic organisms convert _ organic molecules that are used by heterotrophs.

Answer 39

CO2

Question 40

Carbon reservoirs include:

Answer 40

• Fossil fuels, soils, and sediments
• Solutes in oceans
• Plant and animal biomass
• The atmosphere
• Sedimentary rocks

Question 41

Phosphorus is a major constituent of _, phospholipids, and ATP.

Answer 41

Nucleic acids

Question 42

_ is the most important inorganic form of phosphorus.

Answer 42

Phosphate (PO4 3-)

Question 43

The largest reservoirs are _ of marine origin, the oceans, and organisms.

Answer 43

Sedimentary rocks

Question 44

Phosphate binds with soil particles, and movement is often _.

Answer 44

Localized

Question 45

Nitrogen is a component of amino acids, _, and nucleic acids.

Answer 45

Proteins

Question 46

The main reservoir of nitrogen is the atmosphere (N2), though this nitrogen must be converted to NH4 + or NO3 - for uptake by plants, via _ by bacteria.

Answer 46

Nitrogen fixation

Question 47

Organic nitrogen is decomposed to NH4 +; NH4 + is decomposed to NO3 -; NO3 - is converted back to _.

Answer 47

N2

Question 48

Decomposers (detritivores), which derive their energy from _, or nonliving organic matter, play a key role in the general pattern of chemical recycling.

Answer 48

Dedritus

Question 49

Rates at which nutrients cycle in different ecosystems vary greatly, mostly as a result of differing rates of _.

Answer 49

Decomposition

Question 50

The rate of decomposition is controlled by:

Answer 50

• Temperature
• Moisture
• Nutrient availability

Question 51

_ decomposition results in relatively low levels of nutrients in the soil; cold and wet ecosystems store large amounts of undecomposed organic matter as decomposition rates are _.

Answer 51

Rapid; low

Question 52

_ return degraded ecosystems to a more natural state.

Answer 52

Restoration ecologists

Question 53

Given enough time, biological communities can recover from many types of _.

Answer 53

Disturbances

Question 54

Restoration ecology seeks to _ the recovery of degraded ecosystems.

Answer 54

Initiate/speed up

Question 55

Two key strategies of restoration ecology are _ and _ of ecosystem processes.

Answer 55

Bioremediation; augmentation

Question 56

Bioremediation

Answer 56

The use of organisms to detoxify ecosystems

Question 57

The organisms most often used for bioremediation are:

Answer 57

• Prokaryotes
• Fungi
• Plants

Question 58

The organisms used for bioremediation can take up, and sometimes metabolize, _ molecules.

Answer 58

Toxic

Question 59

The bacterium Shewanella oneidensis can metabolize _ and other elements to insoluble forms that are less likely to leach into streams and groundwater.

Answer 59

Uranium

Question 60

Biological augmentation

Answer 60

Uses organisms to add essential materials to a degraded ecosystem

Question 61

Nitrogen-fixing plants can increase the available nitrogen in soil, and adding _ can help plants to access nutrients from soil.

Answer 61

Mycorrhizal fungi