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What is an ecosystem?
all living organisms in an area + the physical envrionment
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Primary producer
an autotroph, synthesize its own food form inorganic soruces
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Net Primary Productivity(NPP):
- energy that is invested in new tissue or offspring. represents the amount of energy that is available to other living components of an ecosystem:consumers and decomposers
- -carbon fixed in photosynthesis
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Biomass
organic material that non-photosynthetic organisms can eat
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Trophic levels
- 1.consumers eat living organisms
- 2.primary consumers eat primary producers
- 3.secondary consumers eat primary consumers
- 4.tertiary consumers eat secondary consumers
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gross primary productivity
the total amount of photosynthesis in a given area and time period
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Ectotherms or Endotherms;biomass is more effective in
biomass is more effective in ectotherms, devote much less energy to maintenance than endotherms do
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Biomagnification
increase in concentration at higher levels in a food chain
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NPP is higher on___than____
NPP is higher on land than water
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The terrestrial ecosystems with the highest productivity are located in the______
The terrestrial ecosystems with the highest productivity are located in the wet tropics
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what limits productivity?
- 1.light
- 2.water
- 3.Carbon dioxide
- 4.Nutrients
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What does iron do when released in the ocean?
Iron increases the amount of chlorophyll a in the ocean which increases NPP
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Biogeochemical cycle
the path that an element takes as it moves from abiotic systems through producers, consumers, and decomposers and back again
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Humus
completely decyaed organic material
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what limits the rate at which nutrients move through an ecosystem?
-the decomposition of detritus. Until decomposition occurs, nutrients stay tied up in intact tissue
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The decomposition rate is influenced by:
- 1.abiotic condition; oxygen availability, temperature
- 2. the quality of the detritus
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decompositon is inhibited if detritus is
- 1.low in nitrogen
- 2. high in lignin
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Watershed
areas drained by a single stream
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Pro/cons of nitrogen in ocean
- 1.increases productivity
- 2.decreases biodiversity and forms dead-zones in aquatic environments
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Nitrogen cycle
- Natural source: Biological fixation/lightning
- Human source: Nitrogen fertilizer, fossil fuels
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Phenology
the timing of seasonal events
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NPP is _____on land and _______in the oceans
NPP is increasing on land but decreasing in the oceans
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most of the net primary productivity that is consumed is used for what purpose?
respiration by primary consumers
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What is biomagnification?
-accumualation of certain molecules at high concentration at upper trophic levels
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what is normally the lonegst-lived reservoir for carbon?
Petroleum
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The greatest limiting factor
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How ro measure global warming?
measure average ocean temperature
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