Ecosystems

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Ecosystems
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Important Terms

• Ecosystem a group of organisms and how they
  interact with their living and nonliving
  environment
• Niche an organisms role
• Biotic living or having lived recently
• Abiotic nonliving, long dead
• Producer converts energy from the sun, also
  called an AUTOTROPH

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• Consumer eats other living things, also known
  as a HETEROTROPH
• Primary, Secondary, Tertiary, Quaternary
• Body of water lake, river, pond, etc
• Food chain each organism feeds on the one below
  it
• Food web overlapping food chains in a community

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• Types of heterotrophs
• Herbivores eat plants
• Carnivores eat animals
• Omnivores eat both plants and animals (omni
  all)
• Detritivores eat dead matter (called
  detritus)
• Decomposers break down organic matter

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• Decomposer
• Organic matter was or is living, made mainly
  out of carbon
• Inorganic matter non living, not made out of
  carbon
• Biodiversity diversity of life

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• Biosphere the part of the earth where life
  exists
• Environment all the external factors
  influencing the life of organisms, such as light
  or food supply
• Photosynthesis to convert energy from the sun
  (more details to come later)
• Population the number of individuals in a
  species in one ecosystem

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• For the following slides, write in your notes
  whether the picture is a food web or food chain
• List the producers and consumers in the pictures
  and what they eat.

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Biogeochemical Cycles

• What is a Biogeochemical Cycle?
• Only so much matter on earth because it is acts
  as a closed system.
• Energy enters as sunlight, but no matter usually
  exits or enters.
• Open system Energy AND matter are exchanged.
• These cycles act as a way to recycle matter
  within the biosphere from one form to another.

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Energy Vs. Matter

• Energy is TRANSFERRED
• One-way flow of energy through food-chains and
  food webs.
• Energy from sun goes to plants, which then goes
  to consumers.
• Each trophic level loses 90 of energy as heat.
• Only 10 of energy is used for life processes.
• Matter is TRANSFORMED
• This is why we have biogeochemical cycles.
• Only have a given amount of matter because Earth
  is a closed ecosystem.

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Nutrient Cycles

• Carbon - key ingredient in living tissue
• Carbon-based life forms
• Nitrogen - required for amino acids used in
  protein synthesis
• What are our sources of protein?
• What do we use proteins for?
• Phosphorus - required for DNA and RNA
• Why is this important?

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Water Cycle

• Water is required by all living things on Earth,
  including us.
• Cycles through atmosphere, ocean, and land

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Water Cycle

• Major processes that bring water into the
  atmosphere
• Evapotranspiration
• Evaporation - water heats up, forming water
  vapor, which then moves into atmosphere.
• Transpiration - water from plant leaves
  evaporates.
• Condensation
• Cloud formation as water vapor in atmosphere
  cools, condensing into the small droplets that
  form clouds.

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Water Cycle

• Major process that brings water out of the
  atmosphere
• Precipitation
• Droplets that formed clouds become to large and
  are released as snow, sleet, hail, or rain.

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Water Cycle

• Processes on land
• Runoff
• Precipitation runs along land until it reaches
  a body of water, such as a lake, river, or ocean.
• Seepage (aka infiltration)
• Precipitation seeps (moves into) soil to form
  ground water below the soils surface.
• Root uptake
• Plants absorb ground water from soil via their
  roots.

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Carbon Cycle

• How is carbon taken up and released?
• Photosynthesis, respiration, decomposition
• Erosion, volcanic activity, and other geological
  activity
• Fossil fuel formation (deposition)
• Human activity
• All these activities transfer carbon dioxide.

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Carbon Facts

• 71 of worlds carbon is in the oceans.
• Mostly as carbonate and bicarbonate (dissolved
  ionic forms of carbon dioxide).
• 22 exists as fossils.
• 3 contained in dead organic matter and
  phytoplankton.
• 3 held in terrestrial ecosystems.
• Only 1 within the atmosphere as carbon dioxide.

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Carbon Cycle

• How can carbon get into the ocean?
• Respiration by ocean animals
• Precipitation that contains dissolved carbon
  dioxide
• Erosion of carbonate rocks formed from animal
  skeletons and shells

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Phosphorus Cycle

• Where is a majority of phosphorus located?
• On land in rock and soil minerals.
• In the ocean as sediment.
• Small amount in living organisms, bound within
  organic molecules such as DNA and RNA as well as
  in skeletons of animals.
• Ca5(PO4)3OH (80 skeletons)
• Unlike other nutrients, it DOES NOT enter the
  atmosphere.

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Phosphorus Cycle

• What is the major form that phosphorus is found
  in?
• Phosphate compounds (PO43-)

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Nitrogen Cycle

• What form does most nitrogen exist in?
• Nitrogen gas in the atmosphere (N2)
• Why is this a bad thing?
• This form is not readily usable by most organisms
  and is often considered inert.
• Inert because of a triple covalent bond, which
  is a very strong chemical bond.

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Nitrogen Cycle

• How do we get to a usable form?
• Bacterial nitrogen fixation
• Atmospheric nitrogen fixation
• Decomposition and excretion
• Haber-Bosch process synthetic fertilizer
• What are these usable forms?
• Ammonia (NH3), Nitrate (NO3-) and nitrite (NO2-).

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Nitrogen Cycle

• What can fix nitrogen to a usable form?
• Bacteria
• On root nodules of legumes such as beans convert
  nitrogen gas to ammonia.
• In soils, convert ammonia to nitrates and
  nitrites
• Enzyme necessary for this requires that no
  oxygen be present.

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Nitrogen Cycle

• What process removes usable nitrogen?
• Denitrification
• Bacteria convert nitrates back into nitrogen gas

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