Grade Range
5th-9th
Active Time
105 minutes
Total Time
105 minutes
Area of Science
Environmental Science
Zoology
Key Concepts
food web, food chain, ecosystem, consumer, producer, herbivore, ominvore, carnivore
Credits

Overview

kelp forest, giant kelp forest, fish in kelp

"Giant Kelp Forest" © 2010 Tom Thai

Could you describe the kelp forest food web as a system? Your students will design and use a simple model to test cause and effect relationships or interactions concerning the functioning of a marine food web, ranking their hypothetical ecosystems according to their stability when faced with a natural or man-made disturbance.

NGSS Alignment

This lesson helps students prepare for these Next Generation Science Standards Performance Expectations:
  • 5-LS2-1. Develop a model to describe the movement of matter among plants, animals, decomposers, and the environment.
  • MS-LS2-3. Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.
  • MS-LS2-4. Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations.
  • HS-LS2-6. Evaluate the claims, evidence, and reasoning that the complex interactions in ecosystems maintain relatively consistent numbers and types of organisms in stable conditions, but changing conditions may result in a new ecosystem.
This lesson focuses on these aspects of NGSS Three Dimensional Learning:

Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Developing and Using Models. Develop a model to predict and/or describe phenomena. Use a model to test cause and effect relationships or interactions concerning the functioning of a natural or designed system.
LS2.A: Interdependent Relationships in Ecosystems. 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.

LS2.B: Cycle of Matter and Energy Transfer in Ecosystems. Food webs are models that demonstrate how matter and energy is transferred between producers, consumers, and decomposers as the three groups interact within an ecosystem. Transfers of matter into and out of the physical environment occur at every level. Decomposers recycle nutrients from dead plant or animal matter back to the soil in terrestrial environments or to the water in aquatic environments.

LS2.C: Ecosystem Dynamics, Functioning, and Resilience. Biodiversity describes the variety of species found in Earth's terrestrial and oceanic ecosystems. The completeness or integrity of an ecosystem' biodiversity is often used as a measure of its health. Ecosystems are dynamic in nature; their characteristics can vary over time. Disruptions to any physical or biological component of an ecosystem can lead to shifts in all its populations.

A complex set of interactions within an ecosystem can keep its numbers and types of organisms relatively constant over long periods of time under stable conditions. If a modest biological or physical disturbance to an ecosystem occurs, it may return to its more or less original status (i.e., the ecosystem is resilient), as opposed to becoming a very different ecosystem. Extreme fluctuations in conditions or the size of any population, however, can challenge the functioning of ecosystems in terms of resources and habitat availability.

Moreover, anthropogenic changes (induced by human activity) in the environment—including habitat destruction, pollution, introduction of invasive species, overexploitation, and climate change—can disrupt an ecosystem and threaten the survival of some species.
Systems and System Models. A system can be described in terms of its components and their interactions.

Stability and Change. Small changes in one part of a system might cause large changes in another part. Some systems appear stable, but over long periods of time they will eventually change.

Cause and Effect. Cause and effect relationships may be used to predict phenomena in natural or designed systems.

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Grade Range
5th-9th
Active Time
105 minutes
Total Time
105 minutes
Area of Science
Environmental Science
Zoology
Key Concepts
food web, food chain, ecosystem, consumer, producer, herbivore, ominvore, carnivore
Credits
Free science fair projects.