chapter 42: ecosystems and energy Flashcards Preview

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Flashcards in chapter 42: ecosystems and energy Deck (72)
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1
Q

what is an ecosystem?

A

consists of all the organisms living in a community, as well as the abiotic factors with which they interact

2
Q

what are some examples of abiotic factors that affect ecosystem?

A

1) nutrients
2) temperature
3) salinity
d) weather
e) climate
f) precipitation
g) terrain
h) rocks
i) pH
j) sunlight

3
Q

what two main processes do all ecosystems have?

A

energy flow and chemical cycling

4
Q

what happens to the energy in an ecosystem?

A

no matter what ecosystem we look at, there is energy flow. the energy is transferred from organism to organism through consumption. ultimately, a large portion of the energy is given off as heat, which relates to the second law of thermodynamics

5
Q

where does the energy for an ecosystem come from?

A

the sun

6
Q

can a cycle go on without a continuous input of energy?

A

no

7
Q

what happens to chemicals/ elements/ nutrients in an ecosystem?

A

they are constantly being cycled around. they get transferred and transformed.

8
Q

what is the first law of thermodynamics?

A

energy cannot be created or destroyed, only transferred or transformed

9
Q

what is the second law of thermodynamics?

A

every exchange of energy increases the entropy of the universe

10
Q

what is the law of conservation of mass?

A

matter cannot be created or destroyed.

11
Q

what are sinks?

A

places where nutrients and/or energy can be stored for a long time

12
Q

what are autotrophs?

A

autotrophs build molecules themselves using photosynthesis or chemosynthesis as an energy source. they are always the base of the pyramid

13
Q

what are heterotrophs?

A

they depend on the biosynthetic output of other living organisms.

14
Q

what is biosynthetic output?

A

stuff made by living organisms

15
Q

what is the order energy flows from in a food pyramid?

A

from autotrophs / primary producers -> primary consumers/ herbivores -> secondary consumers / carnivores -> tertiary consumers / carnivores -> quaternary consumers

16
Q

why are the terms herbivores and carnivores not used as much?

A

because they can be omnivore instead of just herbivore or carnivore

17
Q

can organisms be part of two trophic levels?

A

yes

18
Q

what is the level that links all organisms together?

A

detritivores / decomposers

19
Q

what are detritivores?

A

they are consumers that derive their energy from detritus, non-living organic matter (used to be alive and then died)

20
Q

what are some important detritivores?

A

prokaryotes and fungi

21
Q

who feeds on detritrivores?

A

every one

22
Q

what do detritivores do to energy?

A

pass on energy to other microorganisms and release some of it as heat

23
Q

what is primary production?

A

the amount of light converted to chemical energy by autotrophs during a given period of time

24
Q

what is primary production measured in?

A

g/ m^2

25
Q

how do they measured primary production?

A

take the dry mass of all the plants.

26
Q

why is the dry mass of plants taken?

A

because some plants hold more water than others

27
Q

does every ecosystem have the same amount of primary production?

A

no

28
Q

what can vary the level of primary production?

A

1) levels of plants ( a lot of plant life is limited by amount of water)
2) slopes
3) terrains
4) sunlight exposure
5) angle of sunlight (steeper = less sunlight absorbed; perpendicular = more sunlight absorbed)

29
Q

what sets an ecosystems budget?

A

the extent of photosynthetic production sets the spending limit

30
Q

what determines how much energy is available for all the levels above the base?

A

how much energy is on the bottom level

31
Q

what are the most productive ecosystems?

A

tropical rain forests, estuaries, and coral reefs

32
Q

are marine ecosystems productive or unproductive? explain.

A

they are relatively unproductive per unit area, but contribute much to global net primary production because of their volume

33
Q

what controls primary production in marine ecosystems?

A

light and nutrients

34
Q

how does light control primary production in marine ecosystems?

A

the depth of light penetration affects primary production in the photic zone of an ocean or lake. only about half the solar radiation is absorbed in the first 15 m of the water. and only 5-10% reaches a depth of 75 m

35
Q

what is a limiting nutrient?

A

a limiting nutrient is the element that must be added for production in an area

36
Q

what nutrients limit primary production in marine ecosystems?

A

nitrogen and phosphorus

37
Q

what is eutrophication?

A

no more O2 in the water; kills all living organisms in the water

38
Q

what controls primary production in terrestrial ecosystems?

A

temperature and moisture

39
Q

what happens to primary production with moisture?

A

it increases

40
Q

what are some adaptations plants have to access limiting nutrients from soil?

A

1) some plants form mutualism with nitrogen fixing bacteria
2) many plants form mutualisms with mycorrhizal fungi; these fungi supply plants with phosphorus and other limiting elements
3) roots have root hairs that increase surface area
4) many plants release enzymes that increase the availability of limiting nutrients

41
Q

what is secondary production?

A

secondary production of an ecosystem is the amount of chemical energy in food converted to new biomass during a given period of time

42
Q

how much energy is available for the second level?

A

a certain amount of energy from the first level is transferred to the second level

43
Q

how do you find the biomass of the secondary level?

A

dry mass of animals

44
Q

is the level of efficiency for every pyramid the same?

A

no

45
Q

what efficiency rate do birds and mammals have? why?

A

1-3% because we eat a lot of stuff so our bodies can be less efficient, so we can release heat, so the reaction taking place in our bodies happen faster.

46
Q

what efficiency rate do insects and microorganisms have? why?

A

40+% because they don’t have to use as much energy to keep their bodies warm

47
Q

what is trophic efficiency?

A

the % of production transferred from one trophic level to the next

48
Q

what is the average trophic efficiency?

A

10%

49
Q

what do trophic efficiencies allow us to see?

A

how energy is lost when we go up the food chain

50
Q

what do trophic efficiencies take into account?

A

energy lost through respiration and contained in feces, as well as the energy stored in unconsumed portions of the food source

51
Q

what is the amount of chemical energy that reaches the tertiary consumer?

A

0.1%

52
Q

what does a pyramid of net production represent?

A

the loss of energy with each transfer in a food chain

53
Q

why does nothing eat the the tertiary consumer?

A

because it is very inefficient

54
Q

what does each tier in a biomass pyramid represent?

A

the standing crops (the total dry mass of all organisms) in one trophic level

55
Q

is eating meat an efficient or inefficient way of getting energy?

A

inefficient

56
Q

why do rates at which nutrients cycle in different ecosystems vary?

A

because of differing rates of decomposition

57
Q

what is the rate of decomposition controlled by?

A

mostly temperature, also moisture and nutrient availability

58
Q

what does rapid decomposition result in?

A

relatively low levels of nutrients in the soil

59
Q

what type of ecosystems store large amounts of undecomposed organic matter?

A

cold and wet because decomposition rates are low

60
Q

is decomposition fast or slow in anaerobic muds?

A

slow

61
Q

what are biogeochemical cycles?

A

nutrient cycles in ecosystems involve biotic and abiotic components

62
Q

why is carbon important?

A

forms the framework of the organic molecules essential to all organisms. used in macromolecules

63
Q

what is nitrogen important?

A

a part of amino acids, proteins, and nucleic acids. often a limiting plant nutrient

64
Q

why is oxygen important?

A

photosynthesis and respiration; carbohydrates

65
Q

why is sulphur important?

A

amino acids, make up side chains (disulphide bridge)

66
Q

why is phosphorus important?

A

ATP, DNA

67
Q

what is restoration ecology?

A

seeks to initiate or speed up the recovery of degraded ecosystems

68
Q

what are the two strategies of restoration ecology?

A

bioremediation and augmentation of ecosystem processes

69
Q

what is bioremediation?

A

the use of organisms to detoxify ecosystems.

70
Q

what organisms are most used in bioremediation?

A

prokaryotes, fungi, or plants

71
Q

where do we mostly do bioremediation?

A

places where there was a disaster recently. ex. large oil spill or factories

72
Q

what is biological augmentation?

A

uses organisms to add essential materials to a degraded ecosystem