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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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Principles of Ecology:Matter, Energy, and Life

Chapter 2

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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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Carbon-12 Atom

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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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Common Molecules

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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 Exchange

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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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Ecological Food Chain

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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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Trophic Levels

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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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Ecological Pyramids

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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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Hydrologic Cycle

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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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Carbon Cycle

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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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Nitrogen Cycle

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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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Phosphorus Cycle

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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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Sulfur Cycle

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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

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