Science, 2009
  Grade Level:   4-5  
  EALR 4:   Life Science  
  Big Idea:   Ecosystems (LS2)  
  Core Content:   Food Webs                   
  Description:   In prior grades students learned that ecosystems include both plant and animal populations as well as nonliving resources, and that plants and animals depend on one another and on the nonliving resources in their ecosystem to survive. In grades 4-5 students learn how ecosystems change and how these changes affect the capacity of an ecosystem to support populations. Some changes in ecosystems are caused by the organisms themselves. The ability of any organism to survive will depend on its characteristics and behaviors. Humans also play an important role in many ecosystems and may reduce negative impacts through thoughtful use of natural resources. Concepts related to ecosystems, including food webs, make it possible for students to understand the interrelationships among various forms of life and between living things and their environment.  
  Content Standard:   4-5 LS2E All plants and animals change the ecosystem where they live. If this change reduces another organism's access to resources, that organism may move to another location or die.  
Students are expected to:
  • Describe how one population may affect other plants and/or animals in the ecosystem (e.g., increase in Scotch Broom replaces native plants normally eaten by butterfly caterpillars, reducing the butterfly population).