chapter 2Review
Throughout this chapter, we have examined environmental systems. Earth is one large interconnected system. Components of the system follow basic principles of chemistry and biology. Energy is an important component of these systems. Energy conversions are frequently used in systems analysis. Natural systems change over space and time and humans are sometimes major actors in causing system change.
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Module 4 Systems and Matter
Describe how matter comprises atoms and molecules that move among different systems.
Matter is composed of atoms, which are made up of protons, neutrons, and electrons. Atoms and molecules can interact in chemical reactions in which the bonds between particular atoms may change.
Explain why water is an important component of most environmental systems.
Water facilitates the transfer of chemical elements and compounds from one system to another. The molecular structure of water gives it unique properties that support the conditions necessary for life on Earth. These properties are essential to physiological functioning of plants and animals and the movement of elements through systems.
Discuss how matter is conserved in chemical and biological systems.
Matter cannot be created or destroyed, but its form can be changed within chemical and biological systems. This is part of the reason we cannot easily dispose of certain chemical compounds, such as hazardous materials.
Module 5 Energy, Flows, and Feedbacks
Distinguish among various forms of energy and understand how they are measured.
Energy can take various forms, including energy that is stored (potential energy) and the energy of motion (kinetic energy). Joules and calories are two important energy units.
Discuss the first and second laws of thermodynamics and explain how they influence environmental systems.
The first law of thermodynamics states that energy cannot be created or destroyed, but it can be converted from one form into another. The second law of thermodynamics states that in any conversion of energy, some energy is converted into unusable waste energy, and the entropy of the universe is increased. The quantities and forms of energy present in various systems influence the types of organisms in those systems.
Explain how scientists keep track of energy and matter inputs, outputs, and changes to environmental systems.
Systems can be open or closed to exchanges of matter, energy, or both. A systems analysis determines what goes into, what comes out of, and what has changed within a given system. Environmental scientists use systems analysis to calculate inputs to and outputs from a system and its rate of change. If there is no overall change, the system is in steady state. Changes in one input or output can affect the entire system.