Science, 2009
  Grade Level:   9-12  
  EALR 4:   Life Science  
  Big Idea:   Ecosystems (LS2)  
  Core Content:   Maintenance and Stability of Populations                   
  Description:   In prior grades students learned to apply key concepts about ecosystems to understand the interactions among organisms and the nonliving environment. In grades 9-11 students learn about the factors that foster or limit growth of populations within ecosystems and that help to maintain the health of the ecosystem overall. Organisms participate in the cycles of matter and flow of energy to survive and reproduce. Given abundant resources, populations can increase at rapid rates. But living and nonliving factors limit growth, resulting in ecosystems that can remain stable for long periods of time. Understanding the factors that affect populations is important for many societal issues, from decisions about protecting endangered species to questions about how to meet the resource needs of civilization while maintaining the health and sustainability of Earth's ecosystems.  
  Content Standard:   9-11 LS2D Scientists represent ecosystems in the natural world using mathematical models.  
Students are expected to:
  • Draw a systems diagram to illustrate and explain why introduced (nonnative) species often do poorly and have a tendency to die out, as well as why they sometimes do very well and force out native species. *a, *b
    Mathematics Connections
  • *a    A1.8.A    Analyze a problem situation and represent it mathematically.
             7.2.E     Represent proportional relationships using graphs, tables, and equations, and make connections among the representations.
            A1.3.B    Represent a function with a symbolic expression, as a graph, in a table, and using words, and make connections among these representations.
            A1.2.B    Recognize the multiple uses of variables, determine all possible values of variables that satisfy prescribed conditions, and evaluate algebraic expressions that involve variables.
  • *b    A1.6.B    Make valid inferences and draw conclusions based on data.
            A1.7.D   Solve an equation involving several variables by expressing one variable in terms of the others.