Level 2

Alaska Science
Key Element

A student who meets the content standard should understand the transfers and transformations of matter and energy that link living things and their physical environment from molecules to ecosystems (Flow of Matter and Energy).


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Performance Standard Level 2, Ages 8–10

Students describe the cycling of matter and transfer of energy in the local ecosystem.

Sample Assessment Ideas

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Sample Assessment Ideas

  • Students diagram a food chain starting with a local animal (such as salmon or small mammal) and trace the matter and energy back to plants and the sun.

  • Students diagram the cycle of growth, decay, and renewal that begins in a compost pile and continues as the gardener uses the compost on a garden.

Standards Cross-Reference blue rule

Standards Cross-References
( Alaska Department of Education & Early Development Standards

National Science Education Standards

Populations of organisms can be categorized by the function they serve in an ecosystem. Plants and some microorganisms are producers–they make their own food. All animals, including humans, are consumers, which obtain food by eating other organisms. Decomposers, primarily bacteria and fungi, are consumers that use waste materials and dead organisms for food. Food webs identify the relationships among producers, consumers, and decomposers in an ecosystem. (Page 157)

For ecosystems, the major source of energy is sunlight. Energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis. That energy then passes from organism to organism in food webs. (Page 158)



Almost all kinds of animals’ food can be traced back to plants. (Page 119)

Some source of “energy” is needed for all organisms to stay alive and grow. (Page 119)

Over the whole Earth, organisms are growing, dying, and decaying, and new organisms are being produced by the old ones. (Page 119)

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