Alaska Science Performance Standard L3/A14a

Alaska Science
Key Element A14a

A student who meets the content standard should understand the interdependence between living things and their environments (Interdependence).

Performance Standard Level 3, Ages 11–14

Students classify living organisms based on their position and function in a complex food web.

Sample Assessment Ideas

Students discuss the short-term and long-term consequences of removing a specific organism from a food web.
Students describe the relationship of bacteria and plants in the nitrogen cycle.

Expanded Sample Assessment Idea

Expanded Sample Assessment Idea

Students report on a predatory animal in their local area; determine which other predators are in direct competition for food.

Procedure Students will: Choose an animal to study. Make observations, do library and Internet research, contact state park agencies for information, and discuss their assignments with knowledgeable Elders; determine what prey animals these predators eat, and how much territory is required to support each predator. Identify inter-species and intra-species predators in direct competition with one another for food. Illustrate and describe the food chain of the animal. Produce a class poster, written, or oral class report. (The list of predators in an area could become unmanageable if insects are included. Teachers will have to set some limits on types of animals under consideration.) Compare and classify the animals in the food web according to the level they occupy in the food chain. Reflection and Revision Describe the changes that would occur if one predator or one prey were removed from this area? How would other organisms in the food chain be affected? What happens to human consumption when one food animal is no longer available? Why are some predators no longer found in their original area or in our community?	Levels of Performance
	Stage 4	Student work is complete, and shows evidence of clear and logical reasoning. Student conducts a thorough investigation of an animal and produces a detailed food web that includes organisms from all trophic levels of the food chain. Student correctly identifies predators in direct competition with one another and explains how these animals avoid direct competition. Student work shows extensive evidence of transfer and extension of knowledge in a detailed discussion of how an organism’s change affects the food web.
	Stage 3	Student work shows evidence of logical reasoning, but may contain minor errors or omissions. Student conducts an investigation of an animal and produces a food web that includes organisms from all trophic levels of the food chain. Student correctly identifies predators in direct competition with one another and explains how two of these animals avoid direct competition. Student work shows evidence of transfer and extension of knowledge in a discussion of how an organism’s change affects the food web.
	Stage 2	Student work may be incomplete, or contain errors of science fact and reasoning. Student conducts an investigation of an animal and produces a simple food chain. Student may identify another animal that competes for food or other resources. Student work shows limited evidence of transfer and extension of knowledge.
	Stage 1	Student work is largely incomplete, and may contain major misconceptions regarding an animal and its needs or complex food chain.

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

National Science Education Standards

Living systems at all levels of organization demonstrate the complementary nature of structure and function. Important levels of organization for structure and function include cells, organs, tissues, organ systems, whole organisms, and ecosystems. (Page 156)

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)

The number of organisms an ecosystem can support depends on the resources available and abiotic factors, such as quantity of light and water, range of temperatures, and soil composition. Given adequate biotic and abiotic resources and no disease or predators, populations (including humans) increase at rapid rates. Lack of resources and other factors, such as predation and climate, limit the growth of populations in specific niches in the ecosystem. (Page 158)

Benchmarks

In all environments-freshwater, marine, forest, desert, grassland, mountain and others-organisms with similar needs may compete with one another for resources, including food, space, water, air, and shelter. In any particular environment, the growth and survival of organisms depend on the physical condition. (Page 117)

Two types of organisms may interact with one another in several ways: They may be in a producer/consumer, predator/prey, or parasite/host relationship. Or one organism may scavenge or decompose another. Relationships may be competitive or mutually beneficial. Some species have become so adapted to each other that neither could survive without the other. (Page 117)

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