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11/22 quiz Flashcards

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Biology 101 flashcards
1
Q

biogeography

A

study of the spatial distribution of species

wants to explain why species are found where they are

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2
Q

what can studying islands allow us to do?

A

learn a lot about the processes that determine species composition and diversity across the globe

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3
Q

who is the “father of biogeography”? what did he discover?

A

alfred wallace

discovered the fauna of the philippines was more similar to that of africa than of new guinea

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4
Q

what are wallace’s six biogeographic regions?

A

neartic, neotropical, ethiopian, paleartic, oriental, and australasian

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5
Q

what did wallace’s regions coincide with?

A

tectonic plates

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6
Q

what did continental drift do?

A

change locations of continents and oceans

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7
Q

how does a community get its species? (global perspective)

A

migration - depends on dispersal ability

establishing self upon arrival - depends on a/biotic factors

time - new species from speciation (vicariance, local adaptations, etc.)

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8
Q

how many species should an area have?

A

can predict based on speciation and extinction events in an area (ignoring migration)

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9
Q

larger geographic area increases…

A

probability of speciation

speciation often occurs when populations can become isolated (get rid of gene flow)

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10
Q

large areas increase the chance of population…

A

isolation and divergence

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11
Q

larger geographic area decreases…

A

the probability of extinction

larger areas can support larger populations -> less chance of extinction by chance events

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12
Q

larger areas increase the geographic range of species, which in turn…

A

allows species to spread out and decrease extinction risk

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13
Q

smaller populations have a larger probability of…

A

becoming extinct

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14
Q

smaller geographic areas increase the probability of…

A

extinction

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15
Q

what is the species-area relationship?

A

the positive relationship between species richness and area

occurs over a variety of scales

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16
Q

what is the formula for the species-area effect?

A

S = cA^z

to find number of species

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17
Q

what do the variables mean in the species-area effect?

A

S = number of species
A = area
z = slope of the line
c = constant

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18
Q

how can we plot species-area effect?

A

logS = logc +z*logA

logS on y-axis and logA on x-axis

c = intercept of log-log curve

z = slope log-log curve

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19
Q

where have most species-area relationships been studied?

A

islands, even if not literal islands

lakes, mountain tops (“sky islands”), habitat fragments

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20
Q

what predictions can we make based on the species-area relationship?

A

more species on large islands

fewer species on small islands

more isolated islands -> more speciation due to less gene and immigration

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21
Q

what are other contributing factors to the number of species on an island?

A

area of the island

number of species already there (extinction and immigration rates)

habitat heterogeneity

proximity to other islands

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22
Q

who determined the equilibrium theory of island biogeography?

A

MacArthur and Wilson

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23
Q

what is the equilibrium theory of island biogeography?

A

island communities reach an equilibrium number of species

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24
Q

what is the equilibrium number of species on an island dependent on?

A

the immigration and extinction rates of the island

which are both affected by the size of the island and its distance from the mainland

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25
Q

species number doesn’t change, but species ___ does

A

composition

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26
Q

what is “turnover”?

A

replacement species in island equilibrium theory

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27
Q

the number of species on an island is a balance between…

A

immigration (from the mainland)

extinction (of resident species)

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28
Q

how can we find the equilibrium number of species on a graph of number of species on an island and rate of immigration or extinction?

A

where the curves for immigration and extinction intersection

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29
Q

with more species on an island, you can expect…

A

less immigration of new species and more extinction

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30
Q

how can we use the theory of island biogeography practically?

A

when designing protected areas

like forest fragments or nature preserves, isolated patches connected by migration

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31
Q

which island will recover from defaunation the fastest? a close one or a far one?

A

the close one

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32
Q

how can we generally describe islands when considering equilibrium theory of island biogeography?

A

isolated patched connected by migration

ex: forest fragments and nature preserves

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33
Q

how can we apply the EToIB?

A

when designing protected areas

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34
Q

what is the Biological Dynamics of Forest Fragments Project?

A

one of the largest and longest-running ecological experiments to date

researching the role of size, isolation, shape, and configuration of forest fragments on species diversity maintenance

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35
Q

what were the treatment groups in the BDFFP?

A

4 different plots (1, 10, 100, and 1000 ha)

plots surrounded by forest (control) or deforested land (fragments)

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36
Q

what was the primary findings of the BDFFP?

A

diversity declines with isolation

edge effects cause positive feedback loops (exacerbating circumstances)

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37
Q

what were the regenerative findings of the BDFFP?

A

if the area around the fragment is allowed to regenerate after deforestation, fragments would have to be at least 1000 ha to preserve most of the bird species

if land is not allowed to regenerate (which is usually the case w/ agricultural land), we’d need at least 10000 ha fragments

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38
Q

how can lack of regeneration and forest fragmentation affect animal/insect species

A

most birds/insects/arboreal mammals will avoid entering clearings as little as 100 m wide

species become isolated and dispersal is prevented

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39
Q

what was the metatron?

A

structure of enclosed communities

able to remove/add connects with doors and alter climates and temperatures

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40
Q

how did MacArthur and Elton propose that species richness and community stability are related?

A

more diverse communities are more stable

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41
Q

what is stability?

A

the tendency of a community to remain the same in structure and function

more stable = more resistant to disturbances

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42
Q

the higher the species richness of a plot before a drought…

A

the less plant biomass is lost during the drought

up to a threshold of 10-12 species bc the species richness vs drought resistance plot begins to level off

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43
Q

species diversity is related to community stability and what other community functions?

A

primary productivity

soil fertility (resources in soil)

water quality (purification) and availability

O2 and CO2 exchange

resilience (rate)

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44
Q

evidence shows that species diversity have a positive effect on primary productivity, meaning…

A

plots with more species produce higher biomass (grew more)

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45
Q

how is the finding that species div. has a positive effect on primary productivity relevant to human behavior?

A

we typically plant crops with only one species of plant (monocultures), such as corn, meaning this is less efficient for their growth

however, this would also complicate our ability to produce biofuels bc would need microbe that can break down multiple plant species

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46
Q

how are biofuels obtained?

A

fermentation of plants, such as corn or soybeans

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47
Q

Tilman’s experiment showed that “prairie ethanol” generates ___ energy than biofuel made from monocultures

A

more

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48
Q

what is another benefit of prairie ethanol production for the environment?

A

much lower environmental effects that traditional biofuels

  • less fertilizer and pesticides
  • less greenhouse emissions
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49
Q

what is landscape ecology?

A

the study of the causes and consequences of spatial variation across a range of scales

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50
Q

what is a landscape?

A

an area where at least one element is spatially heterogeneous

mosaic of environments/patches

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51
Q

what does heterogeneous mean in terms of landscapes?

A

varies from one place to another

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52
Q

what is a patch?

A

relatively homogeneous area that differs from its surroundings

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53
Q

what is a matrix?

A

element in landscape that is spatially most continuous

background for patch mosaic

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54
Q

landscape dynamics are influenced by patch…

A

size

shape

composition

number

position (isolation)

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55
Q

species dispersal around a landscape (and migration between patches) if impacted by…

A
  • spatial configuration of patches
  • permeability of the matrix
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56
Q

what is meant by matrix permeability?

A

how likely species are to cross it, often species-specific (some species are more likely to cross the matrix)

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57
Q

what’s an example of matrix impermeability?

A

is salt water is between two areas and the organism is unable to swim or survive in that salinity

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58
Q

what are GIS?

A

geographic information systems

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59
Q

what do GIS do?

A

allow us to analyze and display data about a specific area

can include rainfall, vegetation, aerial photos, satellite imagery, and field studies

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60
Q

there are ___ 1 kilometer forest fragments in the US

A

no

we have logging roads in forest preserves

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61
Q

what are edge effects?

A

abiotic and biotic changes at patch boundaries

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62
Q

how can edge effects influence species dispersal?

A

barrier to inner-forest species’ ability to disperse

if there’s no trees, monkeys won’t leave the fragment bc they aren’t used to it and don’t want to

facilitate dispersal of invasive species

loss of humidity and soil moisture can promote invasive plant and beetle growth

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63
Q

how can edge effects change species abundance?

A

promote edge specialists, like deer

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64
Q

how far can edge effects extend?

A

up to 1 km from edge, which is larger than immediately apparent

relevant to US forest fragment sizes

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65
Q

what is SLOSS?

A

the consideration of whether nature preserves should be single large regions or several small ones

also what the best shape would be, consider amount of edge

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66
Q

what motivated SLOSS?

A

“we’re gonna lose stuff either way, but what’s the best way to do it?”

in terms of structuring nature preserves

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67
Q

what are other edge effects?

A

nest predation and parasitism in birds

interactions with domestic animals (cats, dogs, cattle)

legal and illegal hunting

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68
Q

edges can often be called…

A

“biological traps”

bc of potential for adverse effects

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69
Q

what are habitat corridors?

A

continuous connection for movement between patches (amphibians, mammals, etc.)

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70
Q

what are habitat stepping stones?

A

checkpoints allowing for shorter stretches of unsuitable habitat to be crosses (birds, flying insects)

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71
Q

why is facilitating movement (like with corridors and stepping stones) important?

A

increases gene flow and genetic diversity within populations

allows recolonization of locally extinct populations

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72
Q

what are the negative effects of facilitating movement between patches?

A

movement of predators, competitors, and pathogens

this is important to considering conservation options for some species

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73
Q

how can we decide the best way to facilitate species movement between patches?

A

work with local communities to identify goals of self and community to hit as many as possible

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74
Q

unfortunately, many protected areas in the US and elsewhere were designed to…

A

protect scenic places and not species

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75
Q

what’s the best for reserve size?

A

larger

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76
Q

what’s the best for reserve number?

A

one large instead of a few small ones of the same area

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77
Q

what’s the best for reserve proximity?

A

several close together better than far apart

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78
Q

what’s the best for reserve connectivity?

A

connection by corridors is better than unconnected

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79
Q

what’s the best for reserve shape?

A

compact shapes to minimize boundary/edge length

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80
Q

what’s the best for reserve buffer zones?

A

preferred to have a buffer than not have one

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81
Q

most reserves in the US are … directionally

A

N -> S with little elevation

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82
Q

most things will have to move outside their preserve to cope with ___

A

climate change

need to connect isolated reserves/provide corridors

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83
Q

photosynthesis is the ___ of most food chains

A

basis

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84
Q

plants only use a ___ of the visual light spectrum

A

subset; photosynthetic pigments

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85
Q

what is photosynthesis?

A

mechanism of converting sunlight into energy

other organisms can use energy produced (glucose)

86
Q

what is the basic chemical reactions of photosynthesis?

A

light + H2O -> light-dependent reactions

+ CO2 -> calvin cycle

-> glucose and O2

87
Q

how do plants take in CO2?

A

stomata

also used to release water

88
Q

what is the trade-off between CO2 acquisition and H2O preservation?

A

open stomata allows plant to obtain CO2, but also forces H2O loss

closed stomata allows for preservation of H2O but deficiency of CO2

89
Q

what are the photosynthetic pathways?

A

C3, C4, and CAM

90
Q

what are stomata?

A

guard cells that open/close based on ion concentration

91
Q

what is the C3 pathway?

A

photosynthetic mechanism used by most plants

has simultaneous c-fixation and l-d rxns (transfer of e-)

uses RuBisCO - inefficient at converting CO2 and plant needs lots of it

ancestral condition

92
Q

what is RuBisCO?

A

an enzyme that fixes CO2 to a 3C compound

is the most common soluble protein in nature

holds up to 50% of a leaf’s nitrogen content

93
Q

what is the problem with C3?

A

photorespiration: with low CO2, RuBisCO binds to O2 and reverses l-d rxn

94
Q

what do C3 plants need a lot of and a limit of?

A

need high conc. of CO2

spends lots of time with open stomata -> lots of water loss

95
Q

if we increase the conc. of CO2, C3 pathways will become…

A

more efficient

96
Q

what effect do hotter temps have on C3 pathway plants?

A

loss of efficiency - bc losing more water

97
Q

where are C3 plants most likely to be found?

A

cool and wet areas

98
Q

what is the C4 pathway?

A

similar to C3 but uses a different enzyme in the first stage that has a high affinity for CO2

CO2 reaches Calvin cycle in much higher concentrations and stomata doesn’t need to be open as much

derived and independently occurring across various species

99
Q

what is one down side to C4 pathway?

A

it takes more energy overall than C3

needs to produce additional enzyme

100
Q

when is C4 optimal to use?

A

in hot dry weather

used by monocots and grasses

101
Q

where are C4 pathway plants mostly found?

A

subtropical and tropical regions

102
Q

what is the CAM pathway?

A

further adaptation to C4 pathway for extremely dry environments

temporal separation of l-d and C fixation stomata opening (night)

derived and independent origin

103
Q

what is a pro of CAM pathway?

A

better preserves H2O in extremely dry environments

104
Q

what are the down sides to CAM?

A

photosynthetic production rate is slower - slower growing

daytime photosynthesis is restricted by storage of CO2 from the night

105
Q

where and what plants usually use CAM?

A

in deserts

tropical epiphytes - up high and not much contact with soil, limited access to water

desert succulents - usually plants with fleshy water-storing leaves/stems

106
Q

what are other adaptations to control water loss?

A

trichomes, small leaves, waxy leaves

107
Q

what are trichomes?

A

hairs on plants that protect their surface from direct sunlight and trap moisture

108
Q

what do small leaves do to help control water loss?

A

lots of edges break down layers of hot air on leaf surface, facilitate heat dissipation

don’t need big leaves because sunlight is not a limiting resource

109
Q

how do waxy leaves help control water loss?

A

they’re waterproof and reduce evapotranspiration - harder for water to escape

110
Q

what do C3 plants need to survive?

A

moderate temperatures and high humidity

lose 97% of water taken up by roots through transpiration

111
Q

C4 pathway plants lose about ___ times less water to transpiration than C3 plants

A

3

112
Q

under what conditions do C4 plants perform better than C3 plants?

A

high temperatures, intense sunlight, drought, and low CO2 concentrations

113
Q

how do we know which photosynthesis strategy is best?

A

depends on temperature, CO2, and water availability

C3: less efficient in hotter temps

C4: efficient constantly regardless of temp but more energy costly

114
Q

what does 60% of grasses being a C4 pathway and abundance around the equator demonstrate?

A

underlying mechanism to increased biodiversity in these regions

based on efficiency of RuBisCO and photosynthesis

115
Q

how do plants respond to elevated CO2 concentrations?

A

increased photosynthesis -> increased plant growth -> plants are made up of more carbohydrates and lack other nutrients -> soils do not have enough nitrogen to keep up with fast plant growth

116
Q

what happens bc soils can’t keep up with increased plant growth as a result of increased CO2 concentrations?

A

changes in chemical composition of plant tissues occur (more carbs, less protein) -> lower quality food for herbivores -> herbivores eat more food to compensate

117
Q

what can happen in the soils due to the loss of nitrogen richness after increased plant growth?

A

legume plants become more abundant bc they can use mutualisms to obtain nitrogen - ultimately change in species composition

118
Q

what can happen to individual plants when CO2 levels are elevated? (-)

A

stomata can close sooner and remain closed for longer -> less evapotranspiration -> less water use -> higher soil moisture

plants can drown

not as much water goes to atmosphere -> change weather patterns

119
Q

how are plants related to increased CO2 emissions?

A

important role in mitigating the effects of the increase

120
Q

what are the effects increased atmospheric CO2 has had so far?

A
  • soil (water, N availability, how organisms interact)
  • plant chemical composition
  • plant community composition
  • herbivore populations
  • potentially humans
121
Q

what type of effcts have plant chemical and community composition changes had on food chains?

A

bottom-up

122
Q

how do C4 pathways respond to increased CO2 conc.?

A

relatively unresponsive

123
Q

how do C3 pathways respond to increased CO2 conc.?

A

increased growth if nutrients are available

124
Q

how do legumes respond to increased CO2 conc.?

A

increased growth when symbiosis w/ N-fixing bacteria

125
Q

under high nutrient and CO2 conditions, % of C_ plants decreases

A

4

outcompeted by C3 which benefit from increased CO2

126
Q

under low nutrient conditions, % of ___ increases

A

legumes

127
Q

what are nutrients?

A

elements required for development, maintenance, and reproduction

128
Q

what do organisms need other than energy for metabolism and growth?

A

specific chemical elements - nutrients

129
Q

chemical elements/nutrients are constantly cycling between…

A

organisms and their inorganic forms in the environment

130
Q

what is a nutrient cycle?

A

use, transformation, transfer and re-use of nutrient in ecosystem

131
Q

what is an ecological unit?

A

a food web that is broken down into species, substances, and abiotic portions

132
Q

what is the tropic dynamic concept?

A

where components of the system fit in a structure

typically a pyramid, can identify central points

133
Q

why are food chains usually only 4-5 trophic levels in size?

A

it becomes energetically inefficient and too disordered at further levels

134
Q

what are the types of inorganic energy sources?

A

chemicals (oxidation of electron donors) and sunlight

135
Q

what are chemoautotrophs?

A

eubacteria and archaea which derive energy from the oxidation of electron donors in their environment

such as: H2, H2S, or CH4 (methane)

136
Q

what are photoautotrophs?

A

organisms that derive energy from sunlight through photosynthesis

137
Q

why are we able to do energetic accounting for a given ecosystem?

A

because energy can only be transferred, never created or destroyed

138
Q

as energy is lost and we move up in trophic levels we become ___ disordered

A

more

139
Q

what is assimilation?

A

transformation of inorganic elements into organic forms

requires energy as input

ex: photosynthesis

140
Q

what is dissimilation?

A

the transformation of organic forms into inorganic compounds

releases energy as product

ex: respiration

141
Q

why do we obtain less energy in higher trophic levels?

A

bc eating other organisms become less and less efficient

compare to primary producers who take in direct energy from the sun

142
Q

what is primary production?

A

the production of organic compounds from CO2

mainly photosynthesis

143
Q

what is the basis of food webs on the planet?

A

primary production

144
Q

what is gross primary production?

A

the total amount of energy assimilated by producers

145
Q

what is net primary production?

A

the total biomass accumulated in the ecosystem

what is available to consumers

146
Q

what can primary productivity be limited by?

A

light, temperature, water, and/or nutrients

147
Q

how does more direct sunlight affect primary production in the tropics?

A

it is promoted

148
Q

how is primary production impacted by upwelling or shallow waters?

A

promotes bc higher nutrients or higher temp, respectively

149
Q

how does light limit primary production?

A

increases rate of production until saturation point

150
Q

what is the saturation point?

A

when the rate of photosynthesis stops increasing with light intensity bc pigments saturated

151
Q

what is the compensation point?

A

when energy gained through photosynthesis is equal to that used by respiration

152
Q

what causes an organism to be above or below their compensation point?

A

above: energy balance is positive, exceed energy used

below: energy balance is negative, not enough energy to make up for use

153
Q

primary production can vary…

A

across ecosystems

154
Q

how does temperature limit primary production?

A

pp increases with temp, roughly with latitude

optimal temperature can varying with typical climate for that region

ex: temperate species -> 16C while tropical -> up to 38C

155
Q

how does water limit primary production?

A

increased rainfall increases pp, only up to a point

past this point, there is too much rain and productivity decreases

156
Q

why does pp decrease with too much water?

A

waterlogged soil, decreased decomposition, reduced nutrient regeneration

157
Q

how can pp be limited by nutrients?

A

varies for different species, typically in regards to N and P

sometimes increase promotes, sometimes it will overload the organism, other times a specific combination is more effective than any singular increase

158
Q

elevated CO2 can ___ productivity

A

increase

159
Q

how can herbivory control productivity?

A

think of a bell curve: want enough herbivory so that no one species is outcompeting other primary producers but not too much that the plants aren’t able to grow either

160
Q

how can energy flow through an ecosystem? give a generic cycle

A

bedrock and soil minerals -> inorganic soil nutrients -> plant biomass -> plant detritus (feces, dead plant matter, etc.) -> inorganic soil nutrients -> repeat to biomass or run off in groundwater or stream

161
Q

what can assimilated energy do for an organism?

A

respiration, production of growth or storage, or excretion

162
Q

food chains can have ___ or ___ controls

A

top-down or bottom-up

163
Q

what causes top-down controls?

A

primary producer affected by consumers

164
Q

what can cause bottom-up control?

A

abiotic factors affect primary production

165
Q

with each step in a trophic pyramid, ___ of energy is lost

A

80-95%

166
Q

what is trophic efficiency/food chain efficiency?

A

the percentage of energy transferred from one trophic level to the next

167
Q

how can energy loss along a food chain affect hunting?

A

determine what can be done sustainably

168
Q

why are efficiency levels so low?

A

energy is used for:

maintenance, growth, reproduction

excretion of waste

some components are not assimilated (exoskeleton, bone, cellulose)

169
Q

what are trophic cascades?

A

consumer-resource interactions that affect species other than those that are directly involved

domino effect

170
Q

what are food webs?

A

models that help us define energy flows and predator-prey relationships in an ecosystem

171
Q

patterns in food web can chance among …

A

life stages

172
Q

food webs affect community …

A

structure

removal of one species can cause overgrowth of another -> breaks up equilibrium

173
Q

what are the biogeochemical cycles?

A

nitrogen, phosphorus, decomposition, effects of pollution on ecosystems

174
Q

what is a reservoir for most of earth’s nitrogen?

A

the atmosphere (78%)

mostly inaccessible

175
Q

how can nitrogen enter its cycle?

A

microorganisms or lightning

176
Q

how do microorganisms bring nitrogen into a system?

A

free-living bacteria, cyanobacteria, and symbionts (ex: legumes) perform biological fixation

N2 -> NH3

177
Q

how does lightning bring nitrogen into a system?

A

atmospheric fixation by dissolving N into water and forming nitrates (5-8% of total fixation)

N2 -> NO

178
Q

biological processes happen at a ___ rate

A

fast

ex: animals, microbes, detritus, bacteria

179
Q

geological processes occur at a ___ rate

A

slow

ex: inaccessible organic compounds (coal, oil)

180
Q

___% of biological nitrogen fixation comes from free-living bacteria

A

30

use energy from decomposition of detritus

N2 -> ammonia -> nitrite and nitrate by soil bacteria

181
Q

___% of biological nitrogen fixation is done by symbiotic bacteria

A

70%

bacteria living in symbiotic relationships with plants, occur in nodules in roots

182
Q

bacterial nitrogen fixation makes up for ___% of nitrogen assimilated by terrestrial plants

A

12

183
Q

where does bacterial nitrogen fixation comes from other than assimilation by terrestrial plants? how?

A

decomposition

when bacteria die, they release ammonia into the soil

184
Q

how can we lose nitrate in a system?

A

bc nitrate does not bond to clay particles, so it can be picked up in water or blown away

often lost to aquatic systems due to run off if plants don’t use it

185
Q

what can the loss of nitrogen in a system lead to for aquatic systems?

A

euthophication

186
Q

what is nitrification?

A

a dissimilation reaction

in the presence of O2, specialized bacteria: ammonia -> nitrite -> nitrate

187
Q

what is denitrification?

A

a dissimilation reaction

188
Q

when does denitrification happen?

A

soils with low O2 (anaerobic)

result in specialized bacteria that obtain energy by reducing nitrate to nitric oxide or nitrogen gas, which return to the atmosphere

189
Q

true or false: nitrification and nitrogen fixation are the same process

A

false!

fixation takes nitrogen from the atmosphere

190
Q

ammonia is a ___ ___ for most organisms

A

waste product

191
Q

how have humans impacted nitrogen fixation?

A

increased the pool of fixed nitrogen

started in the twentieth century, we have now exceeded N fixation by nonhuman processes

192
Q

what are examples of non-human processes that perform nitrogen fixation?

A

terrestrial, marine, and lightning

193
Q

what are examples of human processes that cause nitrogen fixation?

A

crops, industrial, fossil fuels

194
Q

what is eutrophication?

A

the increase of nutrients in water

195
Q

what does eutrophication cause?

A

dead zones due to hypoxic areas in aquatic systems

196
Q

what is the series of events that causes dead zones after eutrophication?

A

explosive algal blooms due to increase nutrient availability (seemingly infinite resources) -> population growth crashes, especially bc algal are short lived organisms -> lots of decay, which uses oxygen -> hypoxic environment at the bottom of aquatic regions -> other things die

197
Q

how has human activity changed systems’ abilities to manage eutrophication?

A

used to be able to naturally manage but human contributions have exceeded systems’ abilities

198
Q

what can algal blooms result in?

A

O2 depletion, dead zones, large-scale changes, and neurotoxins

199
Q

what can low nitrogen do to a community?

A

increase biodiversity by promoting competition

best competitors survive and when something dies, decomposition allows small organisms to still access nitrogen

200
Q

what does excessive nitrogen do to a community?

A

reduce biodiversity bc whatever population can grow the fastest persists

phenomenon is used by grass fertilizers

201
Q

what can too much nitrogen result in an ecosystem?

A

changes to species composition

some plants increase in primary production, others might even be depleted

202
Q

what effects does nitrogen loading have on terrestrial ecosystems?

A

increase plant production but decrease diversity

shift composition to weedy species

decrease consumer species richness and increase consumer abundance

affect nitrogen and carbon cycling

203
Q

what is a natural solution to our agricultural pest problem? what is interfering with our ability to do it?

A

having predators in the system would help

monocultures interfere with maintenance of that predator

this is why we should have multi-culture crops

204
Q

where do we get phosphorus from in the environment?

A

weathering of rocks bring it into terrestrial systems

205
Q

how can plants uptake phosphate?

A

ions in the soil

206
Q

how do decomposers interact with phosphorus?

A

they break down organic phosphorus

207
Q

why can’t most aquatic systems use phosphorus biologically?

A

it is bound to soil particles which are stuck in the bottom of the system and don’t recycle

208
Q

why is phosphorus needed?

A

for cell membrane and DNA/nucleic acids

209
Q

how do fungi play a role in nutrient cycles?

A

help uptake nutrients, like phosphorus

210
Q

how can nitrogen-fixing plants play a role in primary succession?

A

increase N inputs to the ecosystem and facilitate colonization of other, sometimes invasive, species

bio 220 (11 decks)

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