Ecosystems and their Components

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Ecosystems and their Components

• Chapter 3

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Ecosystem Components

• The Earth is divided into four components that
  all interact together.
• atmosphere (air)
• hydrosphere (water)
• geosphere (rock, soil and sediment)
• biosphere (living things)

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www.sws.uiuc.edu/nitro/biggraph.asp
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Atmosphere

• thin layer of gases surrounding earths surface.
• layers of the atmosphere include
• troposphere
• extends 11 miles above sea level at equator and 4
  miles above sea level at poles.
• contains all air we breathe, including nitrogen
  (78), oxygen (21), and greenhouse gases
  (natural greenhouse effect)
• where all weather occurs
• stratosphere
• next layer, extends 11-31 miles above earths
  surface
• contains ozone to help filter out UV radiation
  (98) global sunscreen

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Hydrosphere

• all water at or near the earths surface
• founds as water vapor, liquid water, ice and
  frozen in permafrost
• 97 of the earths water is found in the ocean
  (cover 71 of earths surface)

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Geosphere

• Layers of soil, rock and sediment at the earths
  surface and in layers below.
• core hot, molten inner layer, mostly iron
• mantle thick rock middle layer made of silicon,
  iron, oxygen and magnesium
• crust outermost layer, contains all nonrenewable
  fossil fuels and minerals, as well as renewable
  soil nutrients and organisms

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Biosphere

• Parts of atmosphere, hydrosphere and geosphere
  where all living components are found
• Ecology study of interactions between organisms
  and their environment
• biotic and abiotic components

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Energy in Ecosystems

• Ecosystems are driven by
• 1. interactions between organisms
• 2. the flow of high-quality energy (sun)
• most energy is absorbed or reflected back into
  space by the atmosphere
• goes to generating winds (1)
• plants, algae and bacteria use to produce
  nutrients (.1)
• natural greenhouse effect (warms earth to sustain
  life)
• 3. cycling of nutrients

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Within an Ecosystem...

• Interactions happen between organisms,
  populations, and communities
• includes both biotic and abiotic components
• all organisms organized into trophic levels
  depending on source of food or nutrients

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Trophic levels and feeding relationships

• Producers
• autotrophs. use photosynthesis (water carbon
  dioxide light ---gt oxygen and glucose)
• includes plants, algae, phytoplankton and some
  bacteria (chemosynthesis)
• Consumers
• heterotrophs. obtain energy by feeding on other
  organisms.
• primary consumers, secondary consumers, tertiary
  consumers.
• herbivores, omnivores and carnivores.
• Decomposers
• consumers that release nutrients from the wastes
  of plants and animals and return those nutrients
  to the soil, air or water for reuse.
• mostly bacteria and fungi.
• detritivores feed on the wastes and dead bodies
  of other organisms and break into smaller
  particles (detritus)
• earthworms and insects vultures (scavengers)

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Cellular Respiration

• producers, consumers, and decomposers within
  their cells use chemical energy to fuel their
  life processes
• aerobic respiration
• glucose oxygen ---gt carbon dioxide water
  energy
• opposite of photosynthesis
• anaerobic respiration
• occurs in the absence of oxygen (fermentation)
• end products include methane, ethyl alcohol,
  acetic acid or hydrogen sulfide

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Energy Cycling

• Illustrated through food chains and food webs
• describes the flow of energy from one trophic
  level to another
• photosynthesis, feeding, and decomposition
• some energy lost to the environment as heat
  through these processes

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• biomass weight of all organic matter contain it
  its organisms
• chemical energy in biomass is transferred from
  one trophic level to another
• energy is lost with each transfer, less is
  available to the next trophic level
• general rule is only 10 of available energy is
  passed between trophic levels, the rest is lost
  (ecological efficiency)
• explains why there are rarely more than 4-5
  trophic levels (not enough energy to support),
  and why more organisms are found in lower trophic
  levels (fewer top carnivores)

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• biomass found in each ecosystem is determined by
  how much solar energy the producers can capture
  and store.
• varies greatly depending on the ecosystem
• gross primary productivity (GPP) rate at which
  an ecosystems producers convert solar energy
  into chemical energy total amount of energy
  captured by producers
• net primary productivity (NPP) rate at which
  producers use photosynthesis to produce and store
  chemical energy minus the rate at which they use
  some of this stored chemical energy through
  aerobic respiration
• this ultimately limits the number of consumers
  that can survive on earth
• more productivity more organisms supported
• highest in estuaries and rainforests

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Cycling of Matter in Ecosystems

• the elements and compounds that make up nutrients
  move continually through air, water, soil, rock,
  and living organisms.
• This is illustrated through five biogeochemical
  (nutrient cycles)
• water, carbon, phosphorus, nitrogen and sulfur
  cycles.

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Importance of Ecosystems