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Biology II > ch. 55 > Flashcards

ch. 55 Flashcards

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1
Q

ecosystem

A

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

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2
Q

2 main processes for dynamics of ecosystem

A
  1. energy flow
  2. chemical cycling
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3
Q

what do ecologists study

A

transformations of energy and matter in an ecosystem and map the movements of chemical elements

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4
Q

first law of thermodynamics

A

energy cannot be created or destroyed, only transferred or transformed

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5
Q

how does energy enter and leave an ecosystem

A
  • enters as solar radiation
  • conserved
  • lost from organisms as heat
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6
Q

second law of thermodynamics

A

every exchange or energy increases entropy of the universe

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7
Q

where is some energy lost in energy conversions

A

heat

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8
Q

law of conservation of mass

A

matter cannot be created or destroyed

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9
Q

chemical elements are ____________ ____________ within ecosystems

A

continually recycled

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10
Q

open systems

A

absorb energy and mass and release heat and waste products

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11
Q

what happens if a nutrient’s outputs from an ecosystem exceed its inputs

A

the nutrient will limit production

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12
Q

autotrophs

A

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

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13
Q

heterotrophs

A

depend on biosynthetic output of other organisms

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14
Q

where do energy and nutrients pass

A
  • primary producers (autotrophs)
  • primary consumers (herbivores)
  • secondary consumers (carnivores)
  • tertiary consumers (carnivores that feed on other carnivores)
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15
Q

detritivores/decomposers

A

heterotrophs that derive their energy from detritus

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16
Q

detritus

A

nonliving organic matter

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17
Q

main detritivores

A

prokaryotes and fungi

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18
Q

what connects all trophic levels

A

decomposition

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19
Q

primary production

A

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

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20
Q

gross primary production (GPP)

A

total primary production

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21
Q

how is GPP measured

A

conversion of energy from light (or chemicals) to the chemical bond energy of organic molecules per unit time

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22
Q

net primary production (NPP)

A

GPP - Ra
- Ra = energy used by autotrophs for respiration
- amount of new biomass added in a given time period

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23
Q

on average, NPP is ________ GPP

A

one-half

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24
Q

how is primary production expressed

A
  1. energy per unit area per unit time
  2. bio mass added per unit area per unit time
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25
only what is available to consumers
NPP
26
most productive ecosystems per unit area
- tropical rain forests - estuaries - coral reefs
27
why do marine ecosystems contribute much to global net primary production if they are unproductive
because of their size
28
what limits primary production in marine/freshwater ecosystems
light and nutrients
29
what affect primary production in the photic zone of oceans/lakes
depth of light penetration
30
limiting nutrient
element that must be added for production to increase in an area
31
nutrients that most often limit marine production
nitrogen and phosphorus
32
what does the upwelling of nutrient-rich waters in parts of oceans contribute to
regions of high primary production
33
what causes eutrophication of lakes
sewage runoff
34
eutrophication of lakes
- nutrient inputs from sewage promote growth of primary producers - detritivores use up dissolved oxygen, breaking down dead producers - loss of oxygen leads to fish death
35
what does phosphorus limit in lakes
cyanobacterial growth - more than nitrogen
36
what affects primary production on a large scale in terrestrial ecosystems
temperature, moisture, soil nutrients
37
what does NPP increase with in terrestrial ecosystems
precipitation, increasing temperature, and solar energy
38
most common limiting nutrient in terrestrial ecosystems
nitrogen - phosphorus as well, but in older soils
39
adaptations of plants to access limiting nutrients from soil
- mutualisms with nitrogen-fixing bacteria - mutualisms w/ mycorrhizal fungi - root hairs to increase surface area - enzymes that increase availability of limiting nutrients
40
secondary production
amount of chemical energy in food converted to new biomass during a given period of time
41
when a caterpillar feeds on a leaf...
only about 1/6 of leaf's energy used for secondary production
42
efficiency of birds/mammals
1-3% because of high cost of endothermy
43
efficiencies of fish
10%
44
efficiencies of insects and microorganisms
40% or more
45
trophic efficiency
percentage of production transferred from one trophic level to the next
46
usual value of trophic efficiency
10%, range of 5-20%
47
trophic efficiency is ________ over the length of a food chain
multiplied
48
how much of chemical energy fixed by photosynthesis reaches a tertiary consumer
0.1%
49
energy pyramid
represents loss of energy w/ each transfer in a food chain
50
biomass pyramid
each tier represents dry mass of all organisms in one trophic level - show sharp decrease at higher levels
51
inverted biomass pyramids of certain aquatic ecosystems
products (phytoplankton) are consumed so quickly that they are outweighed by primary consumers - zooplankton larger
52
who plays a key role in the general pattern of chemical cycling
decomposers/cycling
53
what is the rate of decomposition controlled by
- temperature - moisture - nutrient availability
54
what does rapid decomposition result in
relatively low levels of nutrients in the soil
55
what do cold and wet ecosystems store
large amounts of undecomposed organic matter, as decomposition rates are low
56
what slows in anaerobic conditions
decomposition
57
biogeochemical cycles
nutrient cycles that involve both biotic and abiotic components
58
what occur in the atmosphere and cycle globally
gaseous carbon, oxygen, sulfur, and nitrogen
59
less mobile elements
phosphorus, potassium, and calcium
60
what is essential to all organisms
water and carbon-based organic molecules
61
where is 97% of biosphere's water
oceans
62
2% of biosphere's water
glaciers and polar ice caps
63
1% of biosphere's water
lakes, rivers, groundwater
64
how does water move (Water Cycle)
- evaporation - transpiration - condensation - precipitation - movement through surface and groundwater
65
what do photosynthetic organisms convert CO2 to
organic molecules consumed by heterotrophs
66
carbon reservoirs inclue (carbon cycle)
- fossil fuels - soils and sediments - solutes in oceans - plant and animal biomass - atmosphere - sedimentary rocks
67
how is CO2 taken up and released
photosynthesis and respiration
68
what also contributes to CO2 in atmosphere
volcanoes and burning of fossil fuels
69
what is nitrogen a component of
amino acids, proteins, and nucleic acids
70
main reservoir of nitrogen
atmosphere (N2)
71
how do plants uptake nitrogen
N2 from atmosphere must be converted to NH4+ or NO3- via nitrogen fixation by bacteria - some bacteria can also use NO2-
72
animals can only use ____________ nitrogen
organic
73
ammonification
organic nitrogen decomposed to NH4+
74
nitrification
NH4+ decomposed to NO3-
75
denitrification
what converts NO3- back to N2
76
what is phosphorus a major constituent of
nucleic acids, phospholipids, and ATP
77
most important inorganic form of phosphorus
phosphate (PO43-)
78
largest reservoir of phosphorus
- sedimentary rocks of marine origin - soil - oceans - organisms
79
what does the weathering of rocks release
phosphate into the soil, reaches aquatic systems through leaching

Biology II (43 decks)

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