Ecosystems: Components, Energy Flow, and Matter Cycling Chapter 4

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Ecosystems Components, Energy Flow, and Matter
Cycling Chapter 4
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The Nature of Ecology

• What is ecology? It is the study of how organisms
  interact with one another and with their
  non-living environment.
• Ecosystem Organization

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Species

• Groups of organisms that resemble one another in
• Appearance
• Behavior
• Chemistry
• Genetic Makeup
• How they produce their offspring.
• Organisms are members of the same species if
  they
• Can actually or potentially breed with one
  another
• They produce live, fertile offspring

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Population

• Consists of a group of interacting individuals of
  the same species that occupy a specific area at
  the same time.
• Genetic diversity exists within the population
• Changes in population can occur in the following
  areas
• Size
• Age Distribution
• Density
• Genetic Composition
• Habitat - the place where a population or an
  individual organism lives.

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Communities, Ecosystems, and Biospheres

• Community populations of different species
  occupying a particular place a complex
  interacting network of plants, animals, and
  microorganisms.
• Ecosystem a community of different species
  interacting with one another and with their
  nonliving environment of matter and energy.
• Biosphere all of earths ecosystems (anywhere
  where there living things inhabit an area.)

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Atmosphere and Earths Layers
Stratosphere Troposphere Hydrosphere Lithosphere
Crust Upper Mantle Biosphere - contains the
portion of the earth where living and non-living
interact.
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What sustains life on Earth?

• The one-way flow of high quality energy from the
  sun.
• The cycling of matter - atoms, ions, and
  molecules needed for survival by living
  organisms.
• Gravity - allows the planet to hold its
  atmosphere and causes the downward movement of
  chemicals in their matter cycles.

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How does the sun help sustain life on Earth?

• Sun
• giant nuclear fusion reactor
• Radiates energy in all directions as
  electromagnetic radiation
• Makes the 92 million mile trip in a little more
  than 8 minutes
• Supports life on earth by
• Lighting and warming the planet
• Supporting photosynthesis
• Powers the cycling of matter
• Drives climate and weather systems

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What happens to Solar Energy Reaching the Earth?

• Earth receives 1 billionth of the suns output of
  energy
• Energy can be reflected away or absorbed
• Visible light
• Infrared radiation
• Ultraviolet radiation
• Incoming energy does the following
• Warms the troposphere and land
• Evaporates water and cycles it through the
  biosphere
• Generates winds
• A small fraction is used for photosynthesis and
  the production of organic compounds

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What are Biomes?

• Biomes - terrestrial areas of the earth defined
  by their climate (long term patterns of weather)
  and specific life forms (may consist of many
  ecosystems
• Aquatic Life Zones - the aquatic equivalent of
  biomes.

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The Non-Living Components of Ecosystems

• Abiotic - the non-living components the physical
  and chemical factors which influence the living
  organisms.
• Range of Tolerance - how each population handles
  variations in the physical and chemical
  environment (each individual may also vary)
• Law of Tolerance - the existence, abundance, and
  distribution of a species in an ecosystem
  determined by the physical and chemicals levels
  fall within the range tolerated by that species.

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The Non-Living Components of Ecosystems (Cont.)

• Limiting Factor - one factor is more important
  than any other factor in limiting population
  growth.
• Limiting Factor Principle - Too much or too
  little of any abiotic factor can limit or prevent
  the growth of a population even if all others are
  at optimum range.

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Living Components of Ecosystems - Producers

• Autotrophs or self-feeders
• On land green plants (photosynthesis)
• In water algae, plants and phytoplankton
• Specialized bacteria (chemosynthesis - converting
  simple compounds from their environment into more
  complex nutrient compounds)

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Living Componenets of Ecosystems - Consumers

• Hetertrophs or those that depend on energy
  receive through feeding on other organisms or
  their remains
• Herbivores
• Carnivores
• Omnivores
• Scavengers
• Detritivores
• Detritus feeders - extract nutrients from partly
  decomposed organic matter in leaf litter, plant
  debris, and animal dung.
• Decomposers - recycle organic matter to get
  nutrients and releasing the resulting simpler
  organic compounds into the soil and water.

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Importance of Biodiversity

• The different life-forms and life-sustaining
  processes that can best survive the variety of
  conditions currently found on earth.
• Genetic diversity - variety in genetic makeup of
  individuals within a species.
• Species diversity - variety among the species.
• Ecological diversity - variety of the biological
  communities
• Functional diversity - the diversity of the
  biological and chemical process or functions such
  as energy flow and matter cycling needed for
  survival of the species and biological
  communities.

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Benefits and Loss of Biodiversity

• Benefits
• Represents thousands to millions of years of
  adaptation to earths changing environmental
  conditions.
• Raw material for future adaptations
• Loss of Biodiversity Results In
• Reduces the availability of ecosystem services
• Decreases the ability to adapt to changing
  environmental conditions

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Food Chains and Food Webs

• Food Chain - a sequence of organisms each of
  which is a source of food for the next
• Food Web - a complex network of interconnecting
  food chains
• Trophic Level - the feeding level assigned to
  each organism in a system depending on whether it
  is a producers or a consumer and on what it eats
  and decomposes.

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Representing the Energy Flow in an Ecosystem

• Biomass - the dry weight of all organic matter
  contained in its organisms
• Transfer of Energy - with each transfer, some
  energy is degraded and lost to the environment as
  low-quality heat
• Ecological Efficiency - the amount of useable
  energy transferred as biomass from one trophic
  level to the next (10 is typical)
• Pyramid of Energy Flow - shows the decrease in
  usable energy available at each level

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• The earth can support more people if they eat at
  a lower trophic level.
• Food chains and webs dont have more than 4 or 5
  trophic levels because there isnt much energy
  left after four to five transfers.
• Few top carnivores
• Carnivores suffer when ecosystem is disrupted.
• Top carnivores are vulnerable to extinction.

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Representing the Biomass Storage in an Ecosystem

• In a pyramid of biomass!
• Represents the storage of biomass at various
  trophic levels in an ecosystem.
• Land ecosystems - the total biomass at each
  successive level decreases
• Ocean ecosystem - the biomass of primary
  consumers can exceed that of producers because
  the producers are microscopic and grow and
  reproduce rapidly

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Primary Productivity of Ecosystems - GPP

• Gross Primary Productivity (GPP) - the rate at
  which an ecosystems producers covert solar
  energy into chemical energy as biomass.
• Greatest High light, heat, and nutrients
• In shallow waters near continents
• Along coral reeefs
• Upwelling currents
• Lowest low nutrients, light, precipitation
• Deserts and arid regions
• Open ocean

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Primary Productivity of Ecosystems - NPP

• Net Primary Productivity (NPP) - the total
  biomass left after the producers use some for
  their own respiration what is available for use
  by other organisms
• Most Productive Ecosystems -
• Estuaries
• Swamps and marshes
• Tropical rainforests
• Least Productive Ecosystems -
• Open ocean (although low, it produces more of the
  earths NPP than any other ecosystem.)
• Tundra
• Desert
• Agriculture - the goals is to increase the NPPP
  and biomass of selected crop plants.

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Why Does the Worlds Biomass Production Matter?

• The planets NPP limits the number of consumers.
• Humans use, waste, or destroy about 27 of the
  earths total potential NPP and 40 of the
  planets terrestrial ecosystems.

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Connections to Biogeochemical Cycles

• Biogeochemical cycles - the nutrient atoms,
  ions, and molecules that organisms need to live,
  grow, and reproduce are continually cycled from
  the nonliving environment to the living organisms
  and back again.
• Carbon
• Oxygen
• Nitrogen
• Phosphorus
• Hydrologic (water)

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Learning About Ecosystems - Field and Laboratory
Research

• Field Research - involves going into nature and
  observing and measuring the structures of
  ecosystems and what happens in them.
• Laboratory Research - setting up, observing, and
  making measurements of model ecosystems and
  populations under laboratory conditions (must be
  coupled and supported by field reserach)
• System Analysis - develops mathematical and other
  models that stimulate ecosystems
• Can model changes in environmental conditions
• Can help anticipate environmental surprises
• Analyze the effects of various alternative
  solutions to environmental problems.

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Ecosystem Services

• The services provided at no-cost to the
  ecosystems.
• Free water purification!
• Natural biological controls
• Biodiversity
• Natural ecosystems

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Two Basic Principles of Ecosystem Sustainability

• All natural ecosystems and the biosphere achieve
  sustainability by
• Using renewable solar energy as the energy source
• Recycling the chemical nutrients needed for
  survival, growth, and reproduction.