In this unit, students explore the web of relationships that link organisms to each other and to their natural environment. From their experiences, they develop an understanding of the following concepts, skills, and attitudes.

Concepts

• An ecosystem is a community of organisms and its interaction with its environment.
• Organisms can be categorized by the functions they serve in an ecosystem: producers, consumers, or decomposers.
• Organisms in an ecosystem have dependent and interdependent relationships, which can be illustrated by food webs.
• Factors that affect growth and reproduction of organisms in an ecosystem include light, water, temperature, and soil.
• Natural and human-made events can "disturb" an ecosystem.
• A pollutant is anything that can harm living organisms when too much of it is released into an ecosystem. Pollution is the condition that results when pollutants interact with the environment.
• Pollutants can affect the stability of an ecosystem; solutions can be developed to minimize or alleviate the effects of pollutants.
• Model ecosystems can be used to learn more about the complex relationships that exist on earth.

Skills

• Using a hand lens, pH paper, measuring devices, and other testing equipment appropriately.
• Conducting, recording, and organizing daily observations.
• Planning, implementing, and analyzing experiments and drawing conclusions from the results.
• Making and testing predictions.
• Identifying ecosystems as stable or disturbed and recognizing whether the causes of a disturbed ecosystem are natural or human-made.
• Reading for more information about ecosystems and pollution.
• Communicating information through writing, drawing, and discussion.
• Applying previously learned information to analyze a problem and suggest solutions.

Attitudes

• Developing sensitivity toward living things and understanding that human behavior can positively or negatively affect them.
• Respecting evidence from an experiment and recognizing that evidence can inform a decision.
• Developing an interest in investigating ecosystems.
• Recognizing the importance of repeating experiments to get valid test results.