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Instructions for Using This PowerPoint Presentation You may • adjust the size of windows (see instructions below) • move forward to the next slide, or backward to the previous slide using the the arrows – bottom center of the screen. 1 Chapter Two: Principles of Ecology: Matter, Energy and Life from your text, Principles of Environmental Science: Inquiry and Applications, 2nd ed. William and Mary Ann Cunningham. (New York: McGraw-Hill, 2003) 2 Required Reading Chapter Two: "Principles of Ecology: Matter, Energy, and Life.” from your text, Principles of Environmental Science: Inquiry and Applications. 2nd ed. William and Mary Ann Cunningham. (New York: McGraw-Hill, 2003) . 3 Chapter Two Objectives Objectives At the end of this lesson, you should be able to • describe matter, atoms, and molecules; • list the four major kinds of organic compounds in cells; give simple examples of their roles • define energy, and explain the difference between kinetic and potential energy; • explain the principles of conservation of matter and energy and describe how the laws of thermodynamics affect living systems; • explain how photosynthesis captures energy for life and how cellular respiration releases that energy to do useful work in a cell; • define species, populations, biological communities, and ecosystems, and understand the ecological significance of these levels of organization; • discuss food chains, food webs, and trophic levels in biological communities, and explain why there are pyramids of energy, biomass, and numbers of individuals in the trophic levels of an ecosystem; and • explain the importance of material cycles, such as carbon and nitrogen cycles, in ecosystems. 4 Chapter Two Key Terms McGraw-Hill Course Glossary Acids Ecosystem Organic compounds Atom Energy pH Bases First law of thermodynamics Photosynthesis Biological community Biomass Carbon cycle Carnivores Cellular respiration Compound Conservation of matter Consumers Decomposer Ecology Food web Herbivores Ions Kinetic energy Matter Metabolism Potential energy Primary producers Productivity Second law of thermodynamics Species Tropic level Molecules Nitrogen cycle Omnivores 5 Chapter Two - Topics • Energy and Matter in the Environment • Organizing Living Things: Species and Ecosystems • Biochemical Cycles and Life Processes 6 Part 1: Energy and Matter in the Environment To understand how ecosystems function, it is important to first know something about how energy and matter behave - in the universe and in living things. It is also important to understand the basic building blocks of life, starting with cells and organisms, and proceeding to communities and populations. 7 Interrelated Scientific Principles: Matter, Energy and Environment 8 Ecology • The scientific study of relationships between organisms and their environment • Examines the life histories, distribution, and behavior of individual species, as well as the structure and function of natural systems at the level of populations, communities, ecosystems, and landscapes • Encourages us to think holistically about interconnections that make whole systems more than just the sum of their individual parts • Examines how and why materials cycle between the living and nonliving parts of our environment 9 Matter and Energy • Matter and energy are essential constituents of both the universe and living organisms. • Matter - everything that takes up space and has mass • Energy - the capacity to do work 10 Potential vs. Kinetic Energy • Potential energy - stored energy that is latent but available for use • Kinetic energy - the energy contained in moving object 11 Heat and Temperature Heat - describes the total kinetic energy of atoms or molecules in a substance not associated with bulk motion of the substance Temperature - a measure of the speed of motion of a typical atom or molecule in substance Heat and temperature are not the same. A substance can have a low temperature (low average molecular speed) but a high heat content (much mass and many moving molecules or atoms). For example, a lake might feel cold to your hand, but it contains an immense amount of stored heat. 12 Energy Quality Low Quality Energy • Diffused, dispersed, or low in temperature • Difficult to gather and use for productive purposes • Example: heat stored in the oceans High Quality Energy • Intense, concentrated, or high in temperature • Useful in carrying out work • Example: high-voltage electrical energy Many of our most common energy sources are lowquality and must be concentrated or transformed into high-quality sources before they are useful to us. 13 Conservation of Matter Under ordinary circumstances, matter is neither created nor destroyed. It is recycled endlessly. • Matter is transformed and combined in different ways, but it doesn't disappear. Everything goes somewhere. • The atoms and molecules in your body have passed through many other organisms, over millions of years. 14 Properties of Energy Energy cannot be recycled. Energy is reused, but it is constantly degraded or lost from the system. Most energy used in ecosystems originates as solar energy. Green plants convert some of this energy to chemical energy, which is then converted to heat or kinetic energy by the animal that eats the plant. 15 Laws of Thermodynamics First Law of Thermodynamics Energy cannot be created or destroyed, only changed Second Law of Thermodynamics With each successive energy transfer or transformation in a system, less energy is available to do work. Even though the the total amount of energy remains the same, the energy's intensity and usefulness deteriorate. The second law recognizes the principle of entropy, the tendency of all natural systems to move towards a 16 state of increasing disorder. Atoms, Molecules, and Compounds • Most material substances can exist in three interchangeable states: solid, liquid, or gas. • Element - substance that cannot be broken down into simpler substances by ordinary chemical reactions • Atom - the smallest particle that exhibits the characteristics of an element • Molecule - a combination of two or more atoms • Compound - a molecule made up of two or more kinds of atoms held together by chemical bonds 17 Fig. 2.3 18 Periodic Table of the Elements 19 Elements and Environmental Science Just four elements - carbon, hydrogen, oxygen, and nitrogen - make up over 96% of the mass of most organisms. 20 Chemical Bonding • Ionic Bond - Formed when one atom gives up an electron to another atom. • Covalent Bond - Formed when two or more atoms share electrons. – Energy is needed to break chemical bonds. – Energy is released when bonds are formed. 21 Fig. 2.4 22 Water Molecule 23 Water: A Unique Compound • • • • • • • • Sixty to 70 percent of the weight of living organisms Medium in which all of life's chemical reactions occur Good electrical conductor Highest surface tension of any common, natural liquid Liquid over a wide temperature range Expands when it crystallizes, unlike most substances High heat of vaporization High specific heat 24 25 A Chemical Reaction Chemical reactions, the breaking and forming of molecular bonds, create all the simple and complex compounds and substances on which life depends. 26 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 27 Fig. 2.5 28 Cells: The Fundamental Units of Life • Microscopic organisms, such as bacteria and protozoa, are composed of single cells. • The human body contains several trillion cells of about two hundred distinct types. • Enzymes – catalysts that speed up the rate of chemical reactions in living systems • Metabolism - all the energy and matter exchanges that occur within a living cell or organism 29 The Electromagnetic Spectrum The wavelengths of visible light drive photosynthesis. 30 Photosynthesis 31 Light and Dark Reactions of Photosynthesis 32 Respiration 33 Energy Exchange in an Ecosystem 34 Part 2: Organizing Living Things • • • • • • Organism Population Biological Community Ecosystem Biosphere 35 Food Web: Cross-connected Food Chains 36 37 Energy Pyramid Most energy in most ecosystems is stored in the bodies of primary producers. Only about 10 percent of the energy at one energy level passes to the next highest trophic level. 38 Bioaccumulation Lake Laberge, a remote lake in northwestern Canada, has been affected by organic chemicals that have been transported thousands of kilometers by wind and weather. The biggest fish in the lake are extremely contaminated due to bioaccumulation, a steady accumulation of toxins through food webs. 39 The Carbon Cycle 40 The Nitrogen Cycle 41 Nitrogen Fixation The nodules on the roots of this plant contain bacteria that help convert nitrogen in the soil to a form the plant can utilize. 42 The Phosphorous Cycle 43 The Sulfur Cycle 44