Ch. 55

Question 1

An _______ consists of all the organisms living in an area as well as the abiotic factors with which they interact

Answer 1

ecosystem

Question 2

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

Answer 2

energy flow and chemical cycling

Question 3

The _______ states that energy cannot be created or destroyed, only transferred or transformed

Answer 3

first law of thermodynamics

Question 4

Energy enters an ecosystem as _______, is conserved, and is lost from organisms as _______

Answer 4

solar radiation; heat

Question 5

The _______ states that every exchange of energy increases the entropy of the universe

Answer 5

second law of thermodynamics

Question 6

The _______ states that matter cannot be created or destroyed

Answer 6

law of conservation and mass

Question 7

Ecosystems are _______, absorbing energy and mass and releasing heat and waste products

Answer 7

open systems: energy and nutrients can flow in and out of the cycle

Question 8

_______ build molecules themselves using photosynthesis or chemosynthesis as an energy source to connect carbon together

Answer 8

Autotrophs

Question 9

_______ depend on the biosynthetic output of other organisms

Answer 9

Heterotrophs

Question 10

Primary producers are

Answer 10

autotrophs

Question 11

primary consumers are

Answer 11

herbivores

Question 12

Secondary consumers are

Answer 12

carnivores

Question 13

tertiary consumers are

Answer 13

carnivores that feed on other carnivores

Question 14

In marine and freshwater ecosystems, both _______ and _______ limit primary production

Answer 14

light and nutrients

Question 15

_______ and _______ are the main detritivores

Answer 15

Prokaryotes and fungi

Question 16

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

Answer 16

primary production

Question 17

Total primary production is known as the ecosystem’s _______

Answer 17

gross primary production (GPP)

Question 18

GPP minus energy used by autotrophs for respiration (Ra) = _______

Answer 18

Net primary production (NPP)
- usually about half

Question 19

primary production can be expressed as _______ or _______ (units)

Answer 19

energy or biomass

Question 20

NPP is _______ in a given time period, not the total biomass of autotrophs

Answer 20

amount of new biomass added

Question 21

A _______ is the element that must be added for production to increase in an area

Answer 21

limiting nutrient

Question 22

_______ and _______ are the nutrients that most often limit marine production

Answer 22

Nitrogen and phosphorous

Question 23

_______ of nutrient-rich waters in parts of the oceans contributes to regions of high primary production

Answer 23

Upwelling

Question 24

explain what happens to fish due to eutrophication in lakes

Answer 24

1) nutrients promote growth of primary producers
2) detritivores break down all the dead producers and use up all dissolved oxygen
3) no more oxygen in water for fish so they die

Question 25

Why should we use phosphate-free detergents when cleaning our clothes?

Answer 25

Phosphates in our detergent can lead to cyanobacterial growth in the water we dispose our laundry water into. This can have a major impact in that environment due to eutrophication

Question 26

_______ is the most common limiting nutrient in terrestrial ecosystems

Answer 26

Nitrogen

Question 27

_______ can also be a limiting nutrient, especially in older soils

Answer 27

Phosphorus

Question 28

how do plants obtain nitrogen?

Answer 28

mutualistic relationship with nitrogen-fixing bacteria

Question 29

How do plants obtain phosphorus?

Answer 29

mutualistic relationship with mycorrhizal fungi

Question 30

Secondary production of an ecosystem is the amount of _______ converted to new biomass during a given period of time

Answer 30

chemical energy in food

Question 31

birds and mammals: fishes: insects and microorganisms
- efficiency of secondary production

Answer 31

insects and microorganisms > fishes > birds and mammals

Question 32

_______ is the percentage of production transferred from one trophic level to the next

Answer 32

Trophic efficiency

Question 33

In a _______, each tier represents the dry mass of all organisms in one trophic level

Answer 33

biomass pyramid

Question 34

Compare an oceans biomass pyramid with land

Answer 34

oceans ratio of primary producers: primary consumers is switched
- Certain aquatic ecosystems have inverted biomass pyramids: Producers (phytoplankton) are consumed so quickly that they are outweighed by primary consumers

Question 35

The rate of decomposition is controlled by _______, _______, and _______

Answer 35

temperature, moisture, and nutrient availability

Question 36

Rapid decomposition results in relatively _______ levels of nutrients in the soil

Answer 36

low

Question 37

Explain the water cycle

Answer 37

water moves by
1) evaporation
2) transpiration
3) condensation
4) precipitation
5) overall movement through surface and groundwater

Question 38

Explain the Carbon Cycle

Answer 38

1) Photosynthetic organisms convert CO2 to organic molecules that are consumed by heterotrophs, then exhaled
2) Carbon reservoirs include fossil fuels, soils and sediments, solutes in oceans, plant and animal biomass, the atmosphere, and sedimentary rocks

Question 39

explain the Nitrogen Cycle

Answer 39

1) nitrogen reserve in atmosphere (N2)
2) converted to NH4+ or NO3- by bacteria
3) used by plants
4) animals get it through plants
5) converted back

Question 40

Organic nitrogen is decomposed to NH4+ by _______, and NH4+ is decomposed to NO3– by nitrification

Answer 40

ammonification

Question 41

_______ converts NO3– back to N2

Answer 41

Denitrification

Question 42

Explain the Phosphorus Cycle

Answer 42

1) The largest reservoirs are sedimentary rocks of marine origin, soil, the oceans, and organisms
2) Weathering of rocks releases phosphate into the soil, and it reaches aquatic systems through leaching