Ecosystems

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Ecosystems
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Food of the SeaIn The News
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Ecosystem

• Includes abiotic environment community
• Types of organisms of an ecosystem
• Producers
• Consumers
• Decomposers

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Producers

• Make their own food
• Base of the food chain
• Plants photosynthetic protists

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Consumers

• Heterotrophs feed on other organisms
• Kill eat their food

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Decomposers

• Special group of consumers
• Nourishment from dead matter
• Recyclers

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An Ecosystem
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Ecosystem Boundaries

• May or may not be distinct

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Transfer of Nutrients

• Ultimate source of most energy is the sun
• Green plants capture energy from the sun
• Consumers eat producers other consumers
• Detritivores convert organic materials to
  nutrients usable by plants

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Trophic Levels

• Feeding levels transfer of energy
• Producer
• Primary consumer feed on producer
• Secondary consumer eat primary consumer
• Tertiary consumer eat secondary consumer

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Food Chain
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Food Web

• Many species do not strictly feed on one trophic
  level
• Interactions become more complicated
• Food web group of interwoven food chains

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Energy Flow Through Ecosystems

• Most energy is lost does not transfer to the
  next trophic level
• Higher trophic levels must have fewer individuals
• Next highest trophic level has about 1/10th the
  number of individuals, biomass energy

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Flow of Energy
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Numbers in Trophic Levels
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Biomass in Trophic Levels
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Energy in Trophic Levels
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Obtaining Substances for Life

• Materials cycle through ecosystems
• Reservoir area with most of a material
• Examples of ecosystem cycles
• Water (hydrologic cycle)
• Nitrogen
• Phosphorus
• Oxygen
• Carbon

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Water Cycle

• Most living things are primarily water
• Lifes chemical reactions require water
• 90 of water that reaches atmosphere comes from
  plant transpiration
• Atmospheric water condenses

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Water Cycle

• Plants take up about 1000 kg of water to produce
  1 kg of biomass
• Groundwater provides ¼ of water used by humans in
  U.S.
• 2 of U.S. groundwater is polluted
• Industry
• Pesticides

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Carbon Cycle

• CO2 found in atmosphere oceans
• Producers some consumers incorporate carbon
  into organic molecules
• Animals combustion return carbon to atmosphere

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Oxygen Cycling

• Plants use CO2, release O2
• Consumers use O2, release CO2
• Some CO2 is liberated by decomposition

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Nitrogen Cycle

• Important plant nutrient
• Atmosphere is reservoir
• Nitrogen fixing bacteria convert N2 to ammonia

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Phosphorus Cycle

• Required plant nutrient
• Soil has only small amounts
• Animals obtain phosphorus by eating plants

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End chapter 40