Ch 23: Global Ecology

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Ch 23 Global Ecology
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Ecology Terms

• Ecology - the study of the interactions of
  organisms with one another and with the physical
  environment
• Biosphere region where organisms are found from
  the atmosphere to the oceans
• Populations all members of a species within a
  particular area
• Community interacting populations within a
  particular area
• Ecosystem biotic community combined with the
  abiotic environment
• Habitat an organisms place of residence
• Niche an organisms role in the community

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Biotic Community

• Autotrophs (producers) use inorganic nutrients
  outside energy source to produce organic
  nutrients.
• Heterotrophs (consumers) need a source of
  organic nutrients
• Herbivores graze on producers
• Carnivores eat only other animals
• Omnivores feed on both plants and animals
• Scavengers clean up on the dead carcasses of
  larger animals
• Detritivores feed on litter, debris, and dung
• Decomposers complete breakdown of organic
  matter into inorganic nutrients

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Aquatic Ecosystems

• Marine seashores, oceans, coral reefs,
  estuaries
• Freshwater lakes, ponds, rivers, streams

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Terrestrial Ecosystems

• Forests - dominated by trees
• Tropical rain forest
• Coniferous forests (taiga)
• Temperate deciduous forests
• Grasslands - dominated by grasses
• Tropical grasslands (Savannah)
• Temperate grasslands (prairie)
• Deserts - determined by lack of available
  moisture
• Tundra
• Deserts

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Figure 26.13
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Energy Flow Chemical Cycling

• Nutrients cycle through an ecosystem
• Energy eventually changes form and dissipates
  through heat
• Thus, we need constant supply of solar energy

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Energy Flow can be described as

• Food web describes who eats whom
• Food chain shows a single path of energy flow
• Grazing food chain Leaves ? Caterpillars ? Tree
  birds ? Hawks
• Detrital food chain Detritus ? Earthworms ?
  Shrews
• Ecological pyramids shows the flow of energy
  with losses between each trophic level
• Trophic levels - all the organisms that feed on
  that particular level

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Biochemical Cycling

• Biogeochemical cycle - pathway by which chemicals
  circulate through ecosystems and involve both
  biotic geological components.
• Reservoirs fossil fuels, sediments, and rocks,
  that contain inorganic nutrients available only
  on a limited basis to living things
• Exchange pools atmosphere, soil, and water
  which are ready sources of inorganic nutrients
  for living things

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Water Cycle

• Water cycle
• Fresh water evaporates from bodies of water
• Water falls on land and enters the ground,
  surface waters, or aquifers
• Water eventually returns to the oceans
• Human Activities
• Ground water mining when humans withdrawal
  water from aquifers that exceed possibility of
  recharge.
• Pollution of our fresh water

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Phosphorus Cycle

• Phosphate Cycle
• Phosphate is a limited resource located in rocks
  (reservoirs)
• Weathering (i.e. rain) wash away phosphate to
  make it available to producers
• Consumer eat producers
• Decomposition of organisms makes phosphate
  available to producers again
• Human Activities
• Cultural eutrophication over enrichment of
  phosphate due to wastes from livestock,
  fertilizers, sewage this can lead to algal
  bloom and when the algae die off, the enlarged
  decomposer population uses up all the available
  Oxygen, which results in massive fish kill

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Nitrogen Cycle

• Nitrogen Cycle
• The reservoir is the atmosphere and N2 gas must
  be converted to a form usable by producers.
• Nitrogen-fixing bacteria convert nitrogen gas to
  ammonium which producers can use
• Organisms eat plants and then decompose putting
  the Nitrogen back into the soil.
• Human Activities
• Fertilizer use results in the release of nitrous
  oxide, a greenhouse gas that depletes the ozone
  shield resulting in global warming

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Carbon Cycle

• Carbon Cycle
• The reservoir is organic matter and fossil fuels
• The exchange pool is the atmosphere
• Photosynthesis from producers removes CO2 from
  the atmosphere
• Cellular respiration from consumers producers
  returns CO2 to the atmosphere
• Human Activities
• Increase of CO2 in the atmosphere from burning
  fossil fuels causes global warming.

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Global Warming