APES Chapter 3

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APES Chapter 3

• Ecosystems and how they work

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3.1 Matter, Energy and Life

• Atoms basic building blocks of all matter.
  Composed of protons, neutrons and electrons.
  These are, in turn, made of still smaller
  particles.
• Molecules and Compounds two or more atoms
  bonded together in a specific way

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• On the chemical level, the cycle of reproduction,
  death and decay of organisms is a continuous
  process of taking various atoms from the
  environment (food), assembling them into living
  organisms (growth), disassembling them (decay),
  and repeating the process.

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Four Spheres

• Biosphere
• Lithosphere
• Hydrosphere
• Atmosphere
• All spheres are a part of the Earths system and
  interact. No one sphere is independent of any of
  the others.

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Key Elements

• All living things characterized by six key
  elements.
• C, H, O, N, P, S these are the essential
  elements in the environment
• Looking at the chemical nature of the spheres,
  you can see where the six key elements occur in
  the environment.

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Atmosphere- mixture of gasses

• Nitrogen (N2) 78.080
• Oxygen (O2) 20.946
• Argon (Ar) 0.934
• Carbon Dioxide (CO2) 0.038
• Neon (Ne) 0.00182
• Helium (He) 0.000524
• Methane (CH4) 0.00015
• Krypton (Kr) 0.000114
• Hydrogen (H2) 0.00005

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• The three important gases are O2, N2, and CO2 and
  H2O vapor. These gases are normally stable but
  can react chemically to form new compounds.

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Hydrosphere

• The source for hydrogen.
• Hydrogen bonding exists between water molecules
• Below freezing, the hydrogen bond holds the
  molecules together to form the crystalline
  structure, ice
• At temperatures above freezing, H bonding holds
  the molecules close, but allows them to move over
  and around each other

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• In the vapor state, hydrogen bonds break and
  water molecules move into the air independently.
• Water is the most important substance with regard
  to weathering, and climate.

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Lithosphere

• Mineral hard, crystalline, inorganic material
• Rocks are made of small crystals of two or more
  minerals
• Soil consists of particles of many different
  minerals
• Interactions Air, water and minerals interact
  with each other. Gasses from the air and ions
  from minerals may dissolve in water. Natural
  water is a solution containing variable amounts
  of dissolved gases and minerals.

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Organic Compounds

• These are the chemical compounds making up the
  tissues of living organisms. The key chemical
  elements are C, H, O, N, P and S. These bond to
  form proteins, carbohydrates, lipids, nucleic
  acids.
• Plastics are based on C-C bonds.
• We will refer to natural organic compounds and
  synthetic organic compounds

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Inorganic compounds

• All other molecules or compounds, those with
  neither carbon carbon nor carbon hydrogen
  bonds.

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• The elements essential to life are present in the
  atmosphere, hydrosphere or lithosphere in
  relatively simple molecules. In living organisms
  of the biosphere they are organized into highly
  complex organic compounds. During growth and
  reproduction, atoms from simple molecules in the
  environment are used to construct the complex
  organic molecules of an organism. Decomposition
  and decay are the reverse process.

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Energy basics

• In addition to rearranging atoms, chemical
  reactions absorb or release energy.
• Matter and Energy the universe is made up of
  matter and energy.
• Matter is anything that has mass and takes up
  space. Includes solids, liquids and gases,
  living and nonliving.
• Energy - Light, heat, movement and electricity do
  not have mass nor do they occupy space. Energy
  affects matter and changes its position or state.

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Kinetic and Potential Energy

• Kinetic energy is energy of motion includes
  light, heat, physical motion and electrical
  current
• Potential energy is energy in storage includes
  energy stored in chemical bonds (gasoline,
  fuels), gravitational energy (height of
  something), elastic potential energy (stretched
  rubber band, spring)

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• Measuring energy heat energy is commonly
  measured in calories. This is the amount of heat
  needed to raise the temperature of 1 gram of
  water 1 degree C. Food Calories are 1000
  calories or a Kcal.

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• No matter can be moved without the absorption or
  release of energy. No change in matter can be
  separated from its respective change in energy

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• Energy Laws Laws of Thermodynamics.
• The first Law of Thermodynamics The Law of
  Conservation of energy. When all the inputs and
  outputs of energy are carefully measured, they
  are found to be equal. Energy is neither created
  nor destroyed, but may be converted from one form
  to another.

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• The second Law of Thermodynamics In the absence
  of energy inputs, any and every system will
  sooner or later come to a stop as its energy is
  converted to heat and lost. In any energy
  conversion, some of the usable energy is always
  lost.

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• Entropy is a measure of the degree of disorder
  in a system. Increasing entropy means increasing
  disorder. This is the reason that all human-made
  things tend to deteriorate.
• T

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• The conversion of energy and the loss of usable
  energy to heat are both aspects of increasing
  entropy.
• Heat is the lowest most disordered form of
  energy. Its spontaneous flow to cooler
  surroundings is a way for that disorder to
  spread.

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• If you see something gaining potential energy,
  energy is being obtained from somewhere else.
  The amount of energy lost from that somewhere
  else is greater than the amount gained.

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• Energy Changes in Organisms
• The production of organic material from inorganic
  material represents a gain in potential energy.
• All organic molecules making up the tissues of
  living organisms contain high potential energy.
• The breakdown of organic matter releases energy.

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• These properties represent the nature of
  ecosystems and how energy is transferred
  throughout.

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• Producers and Photosynthesis
• Use photosynthesis to make sugar from CO2, H2O,
  and light energy. This releases O2 as a
  by-product.

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• 6 CO2 12 H2O ?C6H12O6 6O2 6 H2O
• Chlorophyll in the cells absorbs the kinetic
  energy of light and uses it to remove the H atoms
  from H2O molecules. The H atoms combine with C
  atoms from CO2 to form a growing chain of carbons
  that eventually turns into a glucose molecule.
  After the H atoms are removed from water, the O
  atoms that remain combine with each other to form
  O2 gas which is released into the air.

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• Key energy steps remove H from h2O, join C
  atoms together to form the bonds forming glucose.
• The bonds in water and CO2 are low potential
  energy. The bonds of glucose are high potential
  energy. More energy goes into the rxn than comes
  out.
• The reaction is only about 2 efficient. We get
  2 calories of glucose formed for each 100
  calories of light energy falling on the plant.

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• Within the plant
• Glucose combines with N, P, S and other minral
  nutrients for making all the other organic
  molecules that make up the tissue of the plant.
• Synthesis of these molecules requires energy as
  do the plants absorption of nutrients from the
  soil. This comes from the breakdown of glucose.
• Storage of glucose is accomplished by converting
  the glucose to starch or oils.

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• The total amount of photosynthetic activity in
  producers is called gross primary production.
  Subtracting the energy consumed by the plants
  themselves yields the net primary production.
  The net primary production is the rate at which
  new organic matter is made available to consumers
  in the ecosystem. The grasses in the Serengeti
  have to produce 560 kg dry weight per km2 per day
  in order to keep up with the rate at which they
  are being consumed.
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