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Transcript of 1 Principles of Environmental Science Inquiry and Applications Third Edition Cunningham Chapter 2...
1
Principles of
Environmental ScienceInquiry and Applications
Third EditionThird Edition
Cunningham • Cunningham
Chapter 2 Lecture Outlines*
*See PowerPoint Image Slides for all figures and tables pre-inserted into PowerPoint without notes.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
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Outline:
• Principles of Matter and Energy• Building Blocks of Life• Chemical Bonds• Acids and Bases• Water• Photosynthesis• Food Webs• Ecological Pyramids• Biogeochemical Cycles
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PRINCIPLES OF MATTER AND ENERGY
• Matter - Has mass and takes up space. Three phases
- Solid- Liquid- Gas
• Law of Conservation of Matter Under normal conditions, matter cannot be
created or destroyed.- There is no away.
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Energy
• Energy - The capacity to do work. Kinetic Energy
- Energy contained in moving objects. Potential Energy
- Stored, latent energy available for use.• Heat - Energy that can be transferred
between objects of different temperature. Specific Heat - Amount of heat required to
warm one gram one degree C.
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Thermodynamics
• First Law - Energy is conserved. Under normal conditions, it is neither
created nor destroyed, but can be transferred or transformed.
• Second Law - With each successive energy transfer or transformation, less energy is available to do work. Entropy (disorder) increases.
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BUILDING BLOCKS OF LIFE
• Atom - Smallest particle that exhibits the characteristics of an element. Protons - Positively charged. Electrons - Negatively charged. Neutrons - Neutral.
• Ions - Charged atoms. Cations - Positive charge. Anion - Negative charge.
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BUILDING BLOCKS OF LIFE CONT’D
• Isotope - Atoms of a single element that differ in atomic mass. Radioactive isotopes spontaneously decay
or shed subatomic particles.- Half Life
Neutrons Alpha, Beta, Gamma particles Positrons
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BUILDING BLOCKS OF LIFE CONT’D
• Molecule Group of atoms that can exist as an
individual unit and that has unique properties.
• Compound A molecule containing different kinds of
atoms.
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Chemical Bonding
• Ionic Bond - Formed when an atom loses or gains one or more electrons.
• Covalent Bond - Formed when two or more atoms share electrons. Energy is needed to break chemical
bonds. Energy is released when bonds are
formed.
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Chemical Reactions
• Reactions start with reactants and produce products. Oxidation - A molecule or atom loses an
electron. Reduction - A molecule or atom gains an
electron.
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Acids and Bases
• Acids are compounds that readily release hydrogen ions (H+) in water.
• Bases are substances that readily take up hydrogen ions (H+) and release hydroxide ions (OH-) in solution.
• Strength measured by concentration of H+. pH scale
- 0-14
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Organic Compounds and Cells
• Organic compounds are molecules, often large and complex, built of carbon atoms.
• Enzymes facilitate chemical reactions in cells. Metabolism refers to the multitude of
enzymatic reactions performed by an organism.
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Qualities of Water
• Weight of living organisms 60-70% water.• Universal solvent
Dissolved salt solutions conduct electricity.• Cohesive, producing capillary action.• Exist as liquid over a wide temperature range.• Expands when crystallizes.• High heat of vaporization.• High specific heat.
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SUNLIGHT• Sun is a fiery ball of exploding hydrogen gas.• Radiant energy classified by wavelengths.
Intense energy has short wavelengths. Lower energy has longer wavelengths.
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SUNLIGHT CONT’D
• Solar energy that reaches the earth’s surface is in, or near, the visible light wavelengths. Drive photosynthesis.
• More than half of the incoming sunlight may be reflected or absorbed by atmospheric clouds, dust, or gases. Short wavelengths are filtered out by
gases in the upper atmosphere.
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Photosynthesis and Respiration
• Photosynthesis• 6H2O + 6CO2 + sun C6H12O6 (sugar) + 6O2
• Cellular Respiration• C6H12O6+6O2 6H2O + 6CO2 + energy
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Energy and Matter in the Environment
• Species - All organisms genetically similar enough to breed and produce live, fertile offspring in nature.
• Population - All members of a species that live in the same area at the same time.
• Biological Community - All populations living and interacting in an area.
• Ecosystem - A biological community and its physical environment. Open vs. Closed
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Food Webs and Trophic Levels
• Productivity refers to the amount of biomass produced in a given are during a given time. Primary Producers - Photosynthesize. Consumers - Eat other organisms.
• Food Webs are series of interconnected food chains in an ecosystem. Trophic Level refers to an individual’s
feeding position in an ecosystem.
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Trophic Levels
• Organisms can also be identified by the kinds of food they consume: Herbivores - Eat plants. Carnivores - Eat animals. Omnivores - Eat plants and animals. Detritivores - Eat detritus. Decomposers - Breakdown complex
organic matter into simpler compounds.
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Ecological Pyramids
• Most ecosystems have huge number of primary producers supporting a smaller number of herbivores, supporting a smaller number of secondary consumers. Second law of thermodynamics.
- Ecosystems not 100% efficient. 10% Rule
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BIOGEOCHEMICAL CYCLES
• Hydrological Cycle Most of earth’s water is stored in the
oceans, but solar energy continually evaporates this water, and winds distribute water vapor around the globe.
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Carbon Cycle
• Carbon serves a dual purpose for organisms: Structural component of organic
molecules. Chemical bonds provide metabolic energy.
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Nitrogen Cycle
• Nitrogen makes up about 78% of the air, but plants cannot use N2, the stable diatomic molecule in air. Plants acquire nitrogen through nitrogen
cycle.- Nitrogen-fixing bacteria.
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Phosphorus Cycle
• Abundant phosphorus stimulates plant and algal productivity. Major component of water pollution.
- Reduced levels of dissolved oxygen.
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Sulfur Cycle
• Sulfur compounds are important determinants of the acidity of water. Particulates may also act as critical
regulators of global climate.• Sulfur cycle is complicated by a large
number of possible oxidation states.
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Summary:
• Matter and Energy• Building Blocks of Life• Chemical Bonds• Acids and Bases• Water• Photosynthesis• Food Webs• Ecological Pyramids• Biogeochemical Cycles