A. BIOLOGICAL SYSTEMS MAY INCLUDE POPULATIONS, PHOTOSYNTHESIS/RESPIRATION,
     LIFE CYCLES, ECOSYSTEMS, NATURAL SELECTION, AND THE CELL.

B. PHYSICAL SYSTEMS MAY INCLUDE ATOMIC STRUCTURE, FORCES ON AN OBJECT,
     ELECTRICAL CIRCUIT, AND THE REACTION MECHANISMS.

C. EARTH SYSTEMS MAY INCLUDE HYDROLOGIC CYCLE, WEATHER, ROCK CYCLE, PLATE
     TECTONICS, AND THE SOLAR SYSTEM.

D. THE BEHAVIOR OF A SYSTEM MAY BE DIFFERENT FROM THE BEHAVIOR OF ITS COMPONENTS.

E. CHANGES IN ONE SYSTEM MAY AFFECT OTHER SYSTEMS DIRECTLY OR INDIRECTLY.

F. OUTPUT FROM SOME PARTS OF A SYSTEM WHICH IS INPUT FOR OTHER PARTS CAN PROMOTE
    OR RETARD A FUNCTION IN THE SYSTEM, OR REDUCE ITS DISCREPANCY FROM SOME DESIRED 
    PARAMETER.

1. The stability of a system can be improved when the system includes appropriate feedback mechanisms.
2. A feedback mechanism is a control system by which one structure can regulate the activities of another structure.

TO UNDERSTAND THE CONCEPTS OUTLINED ABOVE, A STUDENT SHOULD BE ABLE TO:

• Use a graphic organizer to diagram and/or interpret data about systems.
• Predict how a change in one component of a system will change the system.
• Use a graphic organizer to describe how a feedback loop controls a system.
• Describe how the behavior of a system may be different from the behavior of its components.
• Identify the appropriate larger system given descriptions of one or more systems that are components of a larger system.
• Analyze a system to show how the output of one subsystem can become the input for another subsystem.
• Make inferences from observations and from collected data that a system is composed of interacting parts.