5 - LS2.A (C) - Ecosystems - FINAL (WND 1/10/14)

DCI: LS2.A (C) Interdependent Relationships in Ecosystems – A healthy ecosystem is one in which multiple species of different types are each able to meet their needs in a relatively stable web of life. Newly introduced species can damage the balance of an ecosystem.

PE: 5-LS2-1 Develop a model to describe the movement of matter among plants, animals, decomposers, and the environment.

[Clarifcation Statement: Emphasis is on the idea that matter that is not food (air, water, decomposed materials in soil) is changed by plants into matter that is food. Examples of systems could include organisms, ecosystems, and the Earth.] [Assessment Boundary: Assessment does not include molecular explanations.]

This is only one part of a standard that describes interdependent relationships found in ecosystems.  The rest of the standard is here: 

The food of almost any kind of animal can be traced back to plants. Organisms are related in food webs in which some animals eat plants for food and other animals eat the animals that eat plants. Some organisms, such as fungi and bacteria, break down dead organisms (both plants or plants parts and animals) and therefore operate as “decomposers.” Decomposition eventually restores (recycles) some materials back to the soil. Organisms can survive only in environments in which their particular needs are met. A healthy ecosystem is one in which multiple species of different types are each able to meet their needs in a relatively stable web of life. Newly introduced species can damage the balance of an ecosystem. (5-LS2-1)

Even though this is part of a larger standard, the content in this module can stand alone independent of the other content of the standard. The focus of this module should be on the idea that when an ecosystem can support diverse populations, it is healthier. 

The important ideas in this standard are: 

- some ecosystems are healthier than others

- a healthy ecosystem is one that supports the needs of a variety of organisms. 

- a variety of organisms supports a healthy food web

- when new species are introduced to an ecosystem, the balance of the ecosystem can be disrupted. 

Possible Question Starters:

"Which of the following characteristics would belong to a stable, healthy ecosystem?"

correct answer - the ecosystem supports the needs of a variety of types of organisms

incorrect answer - the ecosystem supports a very large number of green plants 

"Which of the following would most likely disrupt the stability of an ecosystem?"

correct answer - the introduction of a new species

incorrect answer - a gradual change in daily temperature