Chapter 3 Ecosystems and Energy

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Chapter 3Ecosystems and Energy
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Chesapeake Bay Salt Marsh Ecosystem

• Chesapeake is an estuary (affected by tides)
• Tidal marshes are special because they
• Purify water
• Protect the coastline
• Provide shelter and breeding grounds for aquatic
  species
• Are one of the most productive ecosystems in
  terms of energy!

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Chesapeake Ecosystem

• Water is salty on the ocean side, brackish in the
  middle, and fresh water at the head of the bay
• Base of the food web is cordgrass (shown in
  photo). This has an advantage since it can grow
  under saline conditions and periodic submergence
  due to tides.
• The bay receives high nutrient levels (N,P) from
  treated human sewage and farm runoff, which
  promotes algal growth (cordgrass too), which
  serve as food for other organisms.

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What is the Chesapeake like?

• Major kinds of life in the salt marsh ecosystem
• Insects
• Millions of mosquitoes and horseflies
• Birds
• Sparrows, hulls, clapper rails
• Shrimp, lobster, crabs, barnacles, worms, clams
  and snails are all present and seek refuge in the
  cordgrass.
• No amphibians live there (salt) but the terrapin
  turtle does.
• Numerous species of fish call the Chesapeake
  homeincluding
• Sea trout, croaker, bluefish, striped bass
• Young species enter from the ocean.
• Meadow voles live along the shores, and are
  excellent swimmers too.and they eat leaves,
  stems and many insects

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What does the Chesapeake Tell Us?

• This ecosystem is interdependent upon human
  inputs (pollutants such as nitrates, phosphates
  and others like oil, gas, etc.) and also its
  natural setting.
• It remains one of the most productive ecosystems
  on the planetbut it is in peril!
• Too much pollutionoverfishingtoo many nutrients
  (eutrophication)oil spills.growing population.
• It is important to protect our most productive
  ecosystems!

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Chesapeake Ecosystem

• Chesapeake also serves as an excellent case study
  in how energy flows through an ecosystem!

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Overview of Chapter 3

• What is Ecology?
• The Energy of Life
• Laws of Thermodynamics
• Photosynthesis and Cellular Respiration
• Flow of Energy Through Ecosystems
• Producers, Consumers Decomposers
• Ecological Pyramid
• Ecosystem Productivity

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Ecology

• Ecology
• eco house logy study of
• The study of interactions among and between
  organisms in their abiotic environment
• Biotic - living environment
• Includes all organisms
• Abiotic - non living or physical environment
• Includes living space, sunlight, soil,
  precipitation, etc.

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Ecology

• Ecologists are interested in the levels of life
  above that of organism

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Ecology Definitions

• Species
• A group of similar organisms whose members freely
  interbreed
• Population
• A group of organisms of the same species that
  occupy that live in the same area at the same
  time
• Community
• Al the populations of different species that live
  and interact in the same area at the same time
• Ecosystem
• A community and its physical (abiotic)
  environment
• Landscape
• Several interacting ecosystems

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Ecology

• Biosphere contains earths communities,
  ecosystems and landscapes, and includes

• Atmosphere - gaseous envelope surrounding earth
• Hydrosphere - earths supply of water
• Lithosphere - soil and rock of the earths crust

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The First Second Law of Thermodynamics

• By Michelle Zicca

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Basic Laws of Thermodynamics

• First Law of Thermodynamics
• energy can neither be created nor destroyed
• Second Law of Thermodynamics
• naturally occurring processes are directional

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First Law of Thermodynamics

• One form of work may be converted into another,
• or, work may be converted to heat,
• or, heat may be converted to work,
• but, final energy initial energy

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2nd Law of Thermodynamics

• We intuitively know that heat flows from higher
  to lower temperatures and not the other
  direction.
• i.e., heat flows downhill just like water
• You cannot raise the temperature in this room by
  adding ice cubes.
• Thus processes that employ heat are inherently
  irreversible.

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Heat/Work Conversions

• Heat transfer is inherently irreversible. This
  places limits on the amount of work that can be
  produced from heat.
• Heat can be converted to work using heat engines
• Jet engines (planes), steam engines (trains),
  internal combustion engines (automobiles)

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Open Closed Systems

• Open system exchanges energy with its
  surroundings
• A closed system is self-contained and isolated
  does not exchange energy with its surroundings.

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Where did the energy go?

• By the First Law of Thermodynamics, the energy we
  put into the water (either work or heat) cannot
  be destroyed.
• The heat or work added increased the internal
  energy of the water.

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Processes that take Place

• Reversible Processes
• A reversible process is a quasi-equilibrium, or
  quasi-static, process with a more restrictive
  requirement.
• Internally reversible process
• The internally reversible process is a
  quasi-equilibrium process, which, once having
  taken place, can be reversed and in so doing
  leave no change in the system. This says nothing
  about what happens to the surroundings about the
  system.
• Totally or externally reversible process
• The externally reversible process is a
  quasi-equilibrium process, which, once having
  taken place, can be reversed and in so doing
  leave no change in the system or surroundings.

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Overview of Thermodynamics

• Two constraints on life processes
• Evolutionary history
• Physics and chemistry
• Living things must play by these rules
• Order is sustained in living things at the
• expense of energy and disorder to the surroundings

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Pictures and Examples
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Three Types of Process
Isothermal process
Adiabatic process
P
System
Adiabat
Isotherm
V
Heat bath or reservoir
Adiabatic free expansion
P
?1
End points
?2
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V
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Photosynthesis, Cellular Respiration, and
Chemosynthesis

• By Wesley Washington

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Photosynthesis

• It is a biological process where plants such as
  algae, and some bacteria take in light energy and
  change it into carbohydrates (sugar).

• Glucose is the molecule that is formed by
  photosynthesis. Glucose is the fuel source of
  plants.

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Photosynthesis

• The carbon dioxide(6CO2) and water(12H2O) is
  synthesized with sunlight to form
  glucose(C6H12O6).
• Left over products include water which is
  stored and Oxygen which is released.

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Aerobic Cellular Respiration

• Is essentially is the process of the cells using
  energy to biological work.
• All organisms need to respire. Plants use glucose
  energy while most animals breathe.
• This process usually needs oxygen, however
  anaerobic bacteria hat lives in waterlogged soil,
  animal intestines (like yours!) and hydrothermal
  vents still respire without oxygen.

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Chemosynthesis

• Happens at hydrothermal vents on the bottom of
  the sea floor.
• Bacteria living there is able to with stand
  temperatures of 392 F
• The vents spew out mineral rich water and toxic
  hydrogen sulfide.

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Chemosynthesis

• The bacteria takes the raw inorganic chemicals
  and process them into food of the bacteria.
• Organisms such as the giant red tube worms have a
  symbiotic relationship with the bacteria allowing
  them to live inside their bodies in exchange for
  the energy they produce.

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Producers, Consumers, and Decomposers by Joey
Harkins

• All organisms are classified as either a
  producer, consumer, or decomposer
• The basis of the classification is on how each
  organism receives its nourishment

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Producers

• Producers (autotrophs)- organisms that
  manufacture complex organic molecules from simple
  inorganic substances, such as CO2 and water, and
  using the energy from the sun .
• For example photosynthetic organisms
• Producers incorporate the chemicals they
  manufacture into their own bodies, becoming food
  sources for other animals.

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Consumers

• Consumers (heterophs)- use the bodies of other
  organisms as a source of food energy and
  bodybuilding materials.
• Four types of consumers
• primary consumers- herbivores, only eat
  producers
• secondary consumers- eat primary consumers
• tertiary consumers- eat secondary consumers
• detritus feeders- consume organic matter, like
  animal carcasses, leaf litter, and feces

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Decomposers

• Decomposers (saprotrophs)- heterotrophs that
  break down dead organic material and use the
  decomposition products to supply themselves with
  energy.
• Decomposers release inorganic molecules, such as
  CO2 and mineral salts, that producers can reuse.
• Bacteria and fungi are some examples of
  decomposers

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• Producers, consumers, and decomposers all play an
  important role in the ecosystem.
• Producers provide food and oxygen for the
  community
• Consumers maintain a balance between producers
  and decomposers.
• Decomposers keep dead organisms and waste
  products to a minimum, while also releasing the
  potassium, nitrogen, and phosphorus from dead
  organisms.

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The Path of EnergyWho Eats Whom in Ecosystems?

• Hunter Longenberger

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In an Ecosystem

• Energy passes from one organism to the next
  through a food chain
• Many interconnected food chain forms a food web
• Within each food chain there are trophic levels

Food web (everything is connected)
Food chain (just one path of energy)
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Food Web
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Trophic levels

• Is where the organism stands in the food web
• This is based on the number energy transfer steps
  to that level
• Tropic levels
• Producers (organisms that photosynthesize)
• Primary consumers (herbivores)
• Secondary consumers (carnivores)
• At every step in the food chain there are
  decomposers

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Trophic levels
Secondary consumers
Primary consumers
Producers
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Energy flow

• It is linear or one way
• Once an organism has used energy it is lost as
  heat and is unavailable for any other organism in
  the ecosystem

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Human Impact on the Antarctic food Web

• Ryan Privitera

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The Antarctic food web

• Everywhere in the world there are predators and
  prey meaning the lower you are on the web means
  that you are a primary source to other species.
• Going from the diversity of the rain forest where
  the web is large and complicated as compared to
  one of the simplest webs, the Antarctic.

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They call us humans.

• The number one environmental problem we face as a
  society simply is our population growth.
• The more humans reproduce the worse off the
  planet is going to be and the number increases
  each day by 353015 babies.
• The united states alone produces 10650 a day.
  Thats an outrageous number and believe it or not
  this is the main reason for impacting any food
  web and we seem to disturb the simplest one.

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Antarctica

• This is a place of vacancy which means no
  civilized human life forms live there year round
  for the reason that tempters can drop to -89.2
  Celsius.
• This baron land is home to penguins, polar bears,
  weddell seals, blackbrowed albatross, leopard
  seals, elephant seals, and crabeater seals.

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Human impacts

• Antarctica is one of the most important research
  centers for environmental warming and melting of
  ice.
• Antarctica's clean air, water and ice of are of
  importance to science for understanding how the
  Earth's environment is changing both naturally
  and as a result of human activity due to the
  increasing hole over the Antarctic.
• Pollution drifts into the air and contaminates
  the normal levels of our atmosphere.

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This is the marine ecosystem.
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The simplicity of the food web.
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Rusting metal in antarctica.
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Rusted metal waste barrells.
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Warming chart
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Realizing our mistakes

• The best way to fix any mistake is not to do it
  again so what we have to do as a society is
  realize that what we do anywhere in the world
  will have serious consequences if we keep living
  like Americans.
• The ignorance of others will ruin this ecosystem
  if we simply keep overusing fuels and not using
  renewable energies.

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Ecological Pyramids

• Maddie Lewis

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• Most energy going from one trophic level to the
  next dissipates into the environment due to the
  second law of thermodynamics.
• Ecological pyramids graphically represent
  relative energy levels at each level
• There are three types of ecological pyramids

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Pyramid of Numbers

• Shows number of organisms at each trophic level,
  greater numbers are shown by a larger area
• In most, organisms at the base of the food chain
  are more abundant
• Inverted pyramids of numbers are when higher
  trophic levels have more organisms, seen in
  decomposers, parasites, etc.

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Pyramid of Biomass

• Biomass- quantitive estimate of total mass or
  amount of living material, indicates fixed energy
• Represented as live weight, total volume or dry
  weight
• Succeeding trophic levels usually show reduction
  of biomass

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Pyramid of Energy

• Illustrates energy of biomass at each level
• Usually measured in kilo-calories per year
• Always have large energy bases and get
  progressively smaller
• Less energy reaches each level because organisms
  use it, and some is lost
• Food webs are short due to dramatic reduction in
  energy

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ECOSYSTEM PRODUCTIVITY

• MERICA

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Gross Primary Productivity

• GPP of an ecosystem is the rate at which energy
  is captured during photosynthesis!

MERICA
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Net Primary Productivity

• NPP is energy in plant tissues after cellular
  respiration has occurred!
• NPP is the amount of biomass found in excess of
  that broken down by plants cellular respiration!

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GPPNPP Respiration
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More!

• Both GPP and NPP are expressed as energy per unit
  area per unit time, or as dry weight.
• Consumers use most energy from NPP for cellular
  respiration and to contract muscles.

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RECENTLY

• In 1986 Peter Vitousek calculated how much of
  global NPP is appropiated for the human economy
  and therefore not transferred to other organisms.
  He determined humans use 32 of the annual NPP of
  land-based organisms.
• In 2001 Stuart Rojstaczer reexamined Vitouseks
  experiment and agreed with his result of 32
  usage.
• In 2007 K. Heinz Erb put 97 of the Earths
  forestry information into a computer model. The
  model states humans are appropriated about 25.

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