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Scientific insights: answers?When do I take action or ‘believe?

•Inductive reasoning: ‘bottom up’–Honey bees Apis mellifera how dothey find their way?

•Deductive reasoning: ‘top down’–Using a general theory, derive atestable prediction about a specificcase: Sea otters as keystonepredators

Widespread melting ofarctic perennial sea ice: 15-20% loss

over 30 years

1979 2003

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Ice-dependent marine mammals

Ringed seal Harp seal Walrus

Polar bear

On December 26, 2004, the world’s largest earthquake in 40years created a series of devastating tsunami’s across 12

countries in South Asia and Africa.

Before and After, Khao Lak,Thailand

Ice Plant and the Problems of InvasiveNon-Native Weeds

Sarah Stuve

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Worldview: what the worldmeans to me (and my kind)

• Religion• Resource abundance• Standard of living• Interaction with ‘outgroups’• Government

• And….?

Imbalances?

• 1/5 of the world’s population live in the 20richest countries (25K/yr)

• Yet…in the U.S 35 million people (1/3children) live without sufficient food.

• U.S spends $38 billion yr. on diet programs

Education and fertility rates(women) 2000

• Inverse relationship (education/TFR)– Ethopia: 6%/6.6– Cambodia: 17%/5.1– Egypt: 80%/3.4– South Africa: 95%/3.1– Italy: 95%/1.3– U.S: 95%/2.0

Religion (2000)

• 83% of the world is religious (5billion people). 2/3 belong to the‘big three’

• Christian: 33%, (2 billion)• Islam: 20%, 1.2 billion• Hindu: 12.5 %, 800 million

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Quality of life indicatorsCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

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U.S. consumption/production

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Haiti and Costa Rica: a casestudy

• History• Religion• Occupation• Government• Status today

How we think, what we believe,how we are governed, allinfluence how we behave,

including our behavior towardsour environment

Energy Flow in the Biosphere• Energy Transformations and Entropy

– 1st and 2nd Laws of thermodynamics• 1st- Energy is neither created nor destroyed; it

just changes forms• 2nd- Without energy input, systems will go

towards higher disorder (Entropy)• Energy Flow

– …at the organismal level- Autotrophs andHeterotrophs

– …at the organellar level: Photosynthesis and CellRespiration

What does this have to do withchemistry: matter and

energy?????• Chemistry is ‘how the world works’, part I• It occurs at a level we can’t really see, but its

effects can be very tangible• The behavior of matter and energy is NOT

dependent on worldview• How you interpret this behavior IS• How you act IS

• Let’s try and understand the basics…

Matter and EnergyMatter qualityPhases of matterTypes of energyEnergy quality

Thermodynamics and energy transferLaws of thermodynamicsAtoms, Molecules and Compounds

Electrons and stabilityBonds and Bond strength

Organic vrs. InorganicChemical reactions

Photosynthesis and respiration

WaterBiogeochemical cycles

Matter quality (as a resource)

• High quality is organized,concentrated and easy to access

• Low quality is dilute anddisorganized

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Phases of matter: heat andpressure change states

• Solid: dense and ‘organized’. Gold orevrs. ‘Panning’ in a river

• Liquid: Atoms hit each other often

• Gas: Atoms vibrate in their own space

But water is different…• Solid: less dense! It

floats• Liquid:• Gas: least dense

• Water doesn’tbehave like mostsubstances…

• Movement ofatoms/molecules

Energy

• The ability to do work, or cause atemperature change (heat transfer)

• Kinetic energy: energy of mass and motion.Temperature is a measure of mKE of amolecule

• Potential energy: stored energy. Energy inchemical bonds

Thermodynamics

• First Law:– Energy in = Energy out– Energy cannot be created or destroyed–it just changes

form• Second Law:

– As energy changes form, some of it degrades– Higher energy form to a lower one

• Law of conservation of matter:– Matter is not created or destroyed, it just changes

physically or chemically

Biological Chemistry

• Inorganic Molecules• Organic Molecules: carbon - creating large,

complex, diverse molecules– Carbohydrates– Lipids– Proteins– Nucleic Acids

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Chemical forms of matter

• Elements: building blocks• Compounds and molecules: water• Mixtures: compounds and

elements: air

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Molecules and compoundsFigure 2.4

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Matter: Elements and Compounds

• 92 naturally occurring elements.– Gold, Oxygen, Nitrogen, etc.

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Periodic table of the elementsFigure 2.2

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Elements and compounds

Matter: Elements and Atoms

• Matter is made of Elements• An element is a substance that cannot be

broken down.• Elements are made up of atoms

– Protons (+)– Neutrons (----)– Electrons (-) smallest

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Electrons occupy ‘shells’• 8 in the outermost shell is ideal!• How do they get there? Share….

Matter: Atoms

• Protons and neutrons are in the center of anatom = nucleus

• Electrons move around the nucleus inorbitals (2 per)

• Orbitals are grouped in shells• Movement of electrons between shells

either requires or releases energy

Atomic Structure• Elements combine to form Compounds

-Compound = NaCl Elements = Na and Cl• Each element is made of one kind of atom

which is different from every other• Atoms are made of protons, electrons and

neutrons• Atomic numbers• Orbitals and electron shells

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Atom (carbon-12)Figure 2.3

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Atoms of the four elementsmost common in life

Molecules and Bonding

• Why do atoms bond together to form molecules?• Ionic Bonding

– Ions donating electrons• Covalent Bonds

– Sharing electrons– Complex Molecules– Polar and Non-polar Covalent Bonds

• Electronegativity• Hydrogen bonds

Molecules and Bonding• Reactive elements can

join together• Ionic Bonds

– Ions donating electrons– One becomes +

One becomes –– These now attract each

other and bond

Molecules and Bonding• Reactive elements can

join together• Ionic Bonds

– Donating electrons• Covalent Bonds

– Sharing electrons– Polar/non-polar

• Hydrogen bonds

Polar and Non-polar bonds

• Polar and Non-polar Covalent Bonds– Electronegativity

Hydrogen Bonds

• Polar moleculescan be weaklyattracted to eachother and formHydrogen Bonds

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Biological Significance of H-bonds:

• An environment for the chemistry of life.• Solubility - polar molecules can dissolve

into solution because of H-bond formationwhereas non-polar molecules cannot

• Stability - Some polar molecules form H-bonds internally. These attractive forcesserve to strengthen their internal structure.

Bond strengths

• #1: ionic• #2: covalent• #3: polar (hydrogen)

• Why does this matter to YOU?

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Organic compoundsCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Organic moleculesFigure 2.6

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• Sodium Chloride• Water• Nitrous oxide• Ammonia• Hydrogen sulfide

• No carbon

Inorganic molecules Chemical Dissociation

• Salts, Acids, andBases

• pH

• Buffers

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• # of molecules in a specific volume• Diffusion and Osmosis:

– Diffusion is the net movement of molecules fromareas of high to low concentration

– Passive - requires no energy input– Osmosis is the movement of water through a

membrane that prevents solutes (large molecules)from passing. Net movement is from high to lowconcentrations

Concentrations of solutions Diffusion

Hypertonic Hypotonic Isotonic

Diffusion goes in all directionsOsmosis- passive transport of

water across a membrane

• The making and breaking of chemical bonds -changing the composition of matter

• Some reactions progress to completion, butMOST are reversible

• Concentration of reactants can affect the rate ofthe reaction

• Chemical equilibrium• Activation energy - some need it• Catalysts - enhance or speed up the reaction

Chemical reactions Chemical Reactions

2H2 + O2 = 2H20

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Photosynthesis/Respiration

Photosynthesis:• Plants use carbon

dioxide and producestarch and oxygen

H2O + CO2 =Starch/sugar + O2

Respiration• Animals use

starch/sugar andoxygen, and producecarbon dioxide

Starch/sugar + O2 =H2O + CO2

6CO2 + 6H2O + = C6H12O6 + 6O2

How do we get to this energy?

• Cellular Respiration– Aerobic (w/ oxygen) need for efficient transfer

6CO2 + 6H2O + = C6H12O6 + 6O2

Properties of Water

• 1. Cohesion and adhesion• 2. High specific heat• 3. High heat of evaporation• 4. High thermal conductivity• 5. Less dense when frozen• 6. Excellent biological solvent

The Magic of Water1. Cohesion and Adhesion

Water is attracted to other water and to otherpolar substances by the charges in thestructure. “Hydrophilic” = water loving.

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2. Excellent biologicalsolvent

3. High heat capacity4. High thermal

conductivity5. Less dense when frozen

The Magic of Water Matter and EnergyMatter qualityPhases of matterTypes of energyEnergy quality

Thermodynamics and energy transferLaws of thermodynamicsAtoms, Molecules and Compounds

Electrons and stabilityBonds and Bond strength

Organic vrs. InorganicChemical reactions

Photosynthesis and respirationWaterBiogeochemical cycles