Give examples to show how the plants and animals depend on one another for survival (e.g., worms decompose waste and return nutrients to the soil, which helps plants grow).
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.
An ecosystem includes all of the populations of living organisms and nonliving physical factors in a given area. Living organisms depend on one another and the nonliving physical factors in their ecosystem to help them survive.