WA.4. Life Science
4-5.LS2. Food Webs: 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.
4-5.LS2A. Students know that 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.
4-5.LS2A.2. Students are expected to 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).
4-5.LS2B. Students know that plants make their own food using energy from the sun. Animals get food energy by eating plants and/or other animals that eat plants. Plants make it possible for animals to use the energy of sunlight.
4-5.LS2B.1. Students are expected to explain that plants make their own food, and animals, including humans, get food by eating plants and/or eating other animals.
4-5.LS2C. Students know that plants and animals are related in food webs with producers (plants that make their own food), consumers (animals that eat producers and/or other animals), and decomposers (primarily bacteria and fungi) that break down wastes and dead organisms, and return nutrients to the soil.
4-5.LS2C.2. Students are expected to compare the roles of producers, consumers, and decomposers in an ecosystem.