Ecology

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Ecology
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Ecology

• Organisms all living things
• Environment everything that surrounds or
  affects an organism, living and nonliving, like
  light, heat, soil, water and air
• Ecology the study of living things and their
  relationship to their environment

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Requirements for Life

• Liquid water
• Carbon and other chemical elements
• Gravity to retain our atmosphere
• Continuous and unwavering energy supply
• Other important factor
• Magnetic field (to protect from solar particles)

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Ecosystem

• A group of organisms
• interacting with each other and
• their surroundings
• Distinguished by different climate, soil,
  vegetation and animals
• Maintains a balance (that can be fragile)

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• The largest terrestrial ecosystems are biomes
• Recognized by their similar characteristics
• Examples Deserts, temperate forests, tropical
  rain forests, oceans, mountains, grasslands,
  rivers, and lakes

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Community

• A group of living things within an ecosystem
• Relatively small changes can change or upset the
  balance of the community and begin a process of
  change
• Species a group of animals that are able to
  breed freely and produce fertile offspring
  (further definition maybe necessary in some cases
  - DNA)
• Population members of the same species sharing
  a habitat

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• Habitat an environment with certain
  characteristics
• Niche the effects an organism has on its
  surroundings and how the surroundings affect the
  organism
• Ecological succession orderly progression of
  changes producing a stable or climax community
  e.g. weeds, grass, shrub, forest

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Food Chain

• Each organism is food for the next in line
• All energy originates from the Sun
• Producers or autotrophs convert this energy to
  organic molecules
• Consumers or heterotrophs - eat other organisms

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• Primary consumers eat plants
• Secondary and tertiary eat the herbivores and
  carnivores respectively
• Omnivores - eat both plants and animals
• Decomposers - eat dead organic material

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Food Web

• Because few organisms eat one kind of food

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• Bioaccumulation - the storage of chemicals within
  an individual organism at higher levels than
  those found in the environment
• Biomagnification when chemicals accumulate at
  increasingly higher concentrations at successive
  levels of the food chain

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Energy Flow

• Trophic level level of energy consumption
  within the food web
• T1 producers
• T2 primary consumers
• T3 secondary consumers

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Energy (an aside)

• The ability or capacity to do work
• Heat, electrical, mechanical or chemical
• Potential energy is stored and available to do
  work
• Kinetic energy is called the energy of motion

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Laws of Thermodynamics

• The study of energy, its functions and
  transformations
• Energy flow from one trophic level to the next
  results in a significant loss of usable energy
• Most energy is used by an organism for movement
  and digestion etc.
• Just 10 15 is stored for use by the next
  predator

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Ecological Pyramids (Fig. 4-5)

• Numbers how many organisms occupy each level
• Biomass
• Energy
• At each trophic
• level there is a
• 90 reduction in
• biomass and energy

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The Carbon Cycle

• Biochemical cycle ties living organisms to the
  physical environment
• Carbon is contained in over 80 of all known
  compounds
• Photosynthesis converts CO2 and H2O to make
  glucose C6H12O6

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Carbon Cycle II

• Long term carbon cycle involves longer term
  geologic processes with time frames in the
  thousands and millions of years

Long term Carbon Cycle
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Carbon Cycle III

• Shorter biological carbon cycle involves
  processes whose time frames are in 10s of years
  to thousands of years

Short term Carbon Cycle
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Carbon Cycle IV

• Relationship between shorter longer term cycles
  is complex
• Involves several feed back loops between the two
  cycles

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Carbon Cycle V
Human impact on carbon cycle
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Nitrogen Cycle

• The circulation of nitrogen through plants and
  animals and back to the atmosphere
• 78 of the atmosphere by volume
• Essential for the manufacture of proteins and
  other molecules vital for growth and reproduction

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• Nitrogen from the atmosphere is removed by
  nitrogen fixation carried on by some bacteria,
  algae and lichens and turned into ammonia,
  nitrates and nitrites
• These substances can be taken up by plant roots
  and used to manufacture proteins

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• Nitrogen compounds return to the soil as animal
  waste and through the decay of dead plants and
  animals
• Denitrifying bacteria return the nitrogen to the
  atmosphere by breaking down nitrites

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The Hydrologic Cycle

• Describes waters circulation through the
  environment
• Only 2 of water taken in by plant roots is used
  in photosynthesis, the rest is released to the
  atmosphere in a process called transpiration

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Ecological Concerns

• Acid deposition (acid rain) mercury
• Ozone depletion
• Species loss
• Global warming
• Population (human) increase

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Ecological Concerns II

• Soil erosion
• Food and water demands
• Deforestation
• Energy use
• Dwindling mineral resources

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• Rain with a pH of less than 5.6 is considered
  acid rain
• Acid precipitation problems are noticed first in
  aquatic systems because soils have a much greater
  buffering capacity
• Acid deposition can leach nutrients from the
  soil, hamper microorganisms that nourish plants
  and release toxic metals

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Ozone Depletion

• CFCs and halons are breaking down the ozone
  molecules in the upper atmosphere
• Increased UV rays cause more cases of skin
  cancer, decreased crop yields, reduces the
  population of certain fish larvae, and reduces
  the life of outdoor paints and plastics

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Global Warming

• Change in global climate due to greater retention
  of planetary surface heat due to
• Burning fossil fuels (coal, oil, gas) other
  combustible fuels (creating green house gases
  like CO2, methane, etc.)
• Clearing the rainforest, and agricultural
  practices
• Environmental feedbacks, methane CO2

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Global Heat Balance for Surface of the Planet

• Energy balance
• Incoming radiation (visible UV)
• Heat mixing distribution
• Outgoing surface radiation (IR)

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Global temperature change
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• Global temperatures have risen over the last
  century and evidence indicates they continue to
  rise
• Global warming results in climate change, that
  alter global weather patterns and regional
  climates
• Sea level has risen nearly 8 in the last century
  and further rises will inundate coastal wetlands,
  erode recreational beaches and increase salinity
  of estuaries and groundwater
• Impacts also include the pH of the worlds oceans
  having impacts on oceanic life (e.g. coral reefs)

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Temperature variation over the last 160 thousand
years as recorded in Greenland ice core data
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Greenland Ice Cores

• Oxygen isotopes in the ice tell us the
  atmospheric temperature at each time
• Trapped air in the ice tells us the composition
  of the atmosphere at each time

Air bubbles
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Species Loss

• Biologic diversity variety and variability
  among living organisms and ecological complexes
• Ecosystem diversity
• Species diversity
• Genetic diversity

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• Estimates of total species are approaching 30
  million
• We are losing 17,500 per year
• Many are untapped resources for agricultural,
  industrial and medicinal development

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Wetlands and Rainforests

• 55 of wetlands in the US have been converted for
  industrial, residential and agricultural purposes
• Although rainforests cover only 7 of the earths
  surface they harbor over 50 of the worlds plant
  and animal species

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Benefits of Sustaining Wetlands

• Species diversity
• Flood control
• Filtration

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Benefits of the Rainforests

• Absorb rainfall and release moisture into the
  atmosphere affecting the worlds weather patterns
• Absorbs a large percentage of the worlds CO2
  emissions
• Controls soil erosion and landslides
• Creates essential oxygen
• Moderates the effects of floods and droughts

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Environmental Protection (NEPA)

• National Environmental Policy Act (1970)
• States our intent to achieve productive and
  enjoyable harmony between the activities of
  humans and the environment

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NEPA II

• Implemented by the EPA
• No enforcement agency, lawsuits from outside the
  government
• Established the Council of Environmental Quality
  CEQ overseeing federal environmental issues

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Environmental Assessment (under NEPA)

• Study of any governmental actions
• May result in the filing of a Finding of No
  Significant Impact FONSI
• Or an Environmental Impact Statement EIS, must
  be prepared for any project if government funding
  or regulations are involved

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NEPA III

• The EPA is a major reviewer of EISs
• The input and disclosure process built into NEPA
  give the public an opportunity to participate in
  the decision-making process
• Many states have statutes that parallel NEPA (New
  York State, SEQR State Environmental Quality
  Review Act)