Structuring the biosphere: biogeography Flashcards

1
Q

what processes turn atoms to life and life to atoms

A

atoms to life: photosynthesis
life to atoms:
respiration

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2
Q

in what form is carbon in plants

A

it is fixed by the plant into a reduced form

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3
Q

what two sources can energy for life come from

A

photosynthesis and chemosynthesis

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4
Q

what element is the basis of all macromolecules that form life on earth?

A

carbon

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5
Q

through which processes do dead biomass and living biomass exchange carbon

A

assimilation and senescence

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6
Q

where is nearly all CO2 sequestered

A

sedimentary rocks

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7
Q

what is the only net sink on earth for CO2

A

the ocean, this makes it an important control

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8
Q

how is the nitrogen cycle stable?

A

balance between processes of nitrogen fixation and denitrification

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9
Q

what is homeostasis

A

self-regulating process by which biological systems tend to maintain stability while adjusting to conditions

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10
Q

describe the main steps of the calcium cycle

A
  1. released from minerals by weathering
  2. resides mils of years in the ocean
  3. biomineralisation- used by organisms to form shells
  4. shells-> limestone, sequesters the calcium
  5. uplift-> calcium weathered and becomes part of soil
  6. passed onto plants and animals
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11
Q

where is sulphur released from

A

volcanic eruptions

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12
Q

how does sulphur increase the albedo

A

sulphur joins with aerosols to whiten the atmosphere

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13
Q

what is soil

A

a weathered rock material altered by the presence of living and decaying organisms so it can support life

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14
Q

what are the smallest parts of soil called

A

colloids

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15
Q

what determines soil texture

A

the relative proportions of different materials in the soil: clay, silt, sand, gravel particles, humus

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16
Q

what distinguishes soil from sediment

A

living organisms

17
Q

what is soil fertility

A

the ability of soil to provide essential nutrients to plants, like phosphorus, potassium and nitrogen

18
Q

describe how soil holds onto nutrients

A

most of components dissolved in water are cations. clay particles are anions, so they hold onto the nutrients

19
Q

what factor influences the solubility of nutrients

A

pH, the hydrogen ion activity

20
Q

provide a few examples of how humans are impacting on biogeochemical cycles

A

artificial fertilisers control the nitrogen cycle,
deforestation and fossil fuel burning releases sequestered carbon, production of cement,
releasing sulphur leads to acidification of rain

21
Q

name 10 terrestrial biomes

A

tundra, boreal forest, temperate rainforest, temperate deciduous forest, tropical rainforest, tropical deciduous forest, savanna, chaparral (mediterranean), grassland, desert

22
Q

name 3 aquatic biomes

A

marine, freshwater, transitional