Energy Flow in Ecosystems and Biogeochemical Cycles

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Energy Flow in Ecosystems and Biogeochemical
Cycles
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Hierarchy of ecology

• Organism - individual living thing
• Population- a group of the same species
• Community a group of different species
• Ecosystem all organisms as well as nonliving
  things in an area
• Biome - a major regional or global community of
  organism - can be as small as the microorganisms
  living on your skin or as large as the entire
  biosphere

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Whats an Ecosystem?

• An ecosystem consists of all the organisms
  (biotic) in a community and the environment
  (abiotic) with which they interact.
• Biotic - living things
• plants animals, fungi, bacteria
• Abiotic - non-living things
• Moisture, temperature, wind,
• sunlight, soil

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Biodiversity

• The assortment, or variety, of living things in
  an ecosystem
• KEYSTONE Species a species that has an
  unusually large effect on its ecosystem

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Herbivore (primary consumer)
Carnivore (secondary consumer)
Producer
Detritivores (decomposers)
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Break down organic materials into simpler
cpmpounds
Get their energy from non-living sources and make
their own food
Get their energy by eating living, or once
living, resources, such as plants and animals
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Energy Flow in Ecosystems

• Almost all energy used in ecosystems comes from
  the sun
• From there it flows through a food chain or web
  and exits the ecosystem in the form of heat,
  light, kinetic or chemical energy

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• A food chain is a sequence that links species by
  their feeding relation

• A food web is a model that shows the complex
  network of feeding relationships and flow of
  energy within an ecosystem

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Types of Consumers

• Decomposers

• Herbivores eat only plants
• Carnivores eat only animals
• Omnivores eat both plants and animals
• Detritivores eat detritis or dead and dying
  organic matter
• Decomposers - - detritivores that break down
  organic matter into simpler compounds (example
  fungi)

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Trophic Levels

• Energy pyramids show the efficiency of energy
  transfer between trophic levels
• Generally 10 of energy is transferred
• Food chains never get beyond 4-5 trophic levels

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Carnivores that eat secondary consumers
Carnivores that eat herbivores
Herbivores because they are the first consumer
above the producer
The first , or bottom, trophic level
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Biogeochemical Cycle
Consumers
Producers
Detritivores
Nutrients available to producers
Abiotic reservoir
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Biogeochemical Cycling of Nutrients

• The movement of a particular chemical through the
  biological and geological, or living and
  non-living parts of an ecosystem.
• Most ecosystems require a constant inflow of
  energy from the sun. In terms of matter, such as
  oxygen and carbon, the Earth is a closed system
  and it recycles its resources.
• Water cycle
• Oxygen cycle
• Carbon cycle
• Nitrogen cycle
• Phosphorous cycle

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Water Cycle

• Solar energy drives the global water cycle
• Precipitation
• Evaporation
• Transpiration
• Water cycles between the land, oceans, and
  atmosphere
• Forest destruction and irrigation affect the
  water cycle

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Transport over land
Solar energy
Net movement of water vapor by wind
Precipitation over land
Precipitation over ocean
Evaporation from ocean
Evaporation and transpiration from land
Percolation through soil
Runoff and groundwater
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Carbon Cycle

• Abiotic reservoirs atmosphere, sedimentary
  rocks, dissolved carbon in oceans, and fossil
  fuels
• Taken from the atmosphere by photosynthesis
• Used to make organic molecules
• Decomposed by detritivores
• Returned to the atmosphere by cellular respiration

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Photosynthesis
Burning of fossil fuels and wood
Decomposition
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Global warming CO2 lets sunlight through but
retains the heat radiated from Earth.
Human activities and natural processes add CO2 to
the atmosphere, increasing the effect.
Photosynthesis removes CO2 from the
atmosphere, decreasing the effect.
CO2
CO2 in the atmosphere
CO2
CO2
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Nitrogen Cycle

• The nitrogen cycle relies heavily on bacteria
• Atmospheric N2 is not available to plants
• Soil bacteria convert gaseous N2 to usable
  ammonium (NH4) and nitrate (NO3-)
• Some NH4 and NO3- are made by chemical reactions
  in the atmosphere

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Nitrogen in atmosphere (N2)
Nitrogen fixation
Assimilation by plants
Denitrifying bacteria
Nitrates (NO3)
Nitrifying bacteria
Ammonium (NH4?)
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Phosphorus Cycle

• Depends on the weathering of rock
• Phosphorus and other soil minerals are recycled
  locally
• Weathering of rock adds PO43- to soil
• Slow process makes amount of phosphorus available
  to plants low

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Runoff
Sedimentation