Students use data to construct a reasonable explanation of how an ecosystem works. Students communicate investigations and explanations. Students discover that all animals depend on plants. Some animals eat plants for food. Other animals eat animals that eat plants.
Students discover that all organisms cause changes in the environment in which they live.
Some of these changes are beneficial and some are detrimental. Humans depend on their natural and constructed environments. Humans change environments in ways that can be beneficial or detrimental for themselves and other organisms. Changes in environments can be natural or influenced by humans. Some changes are good, some are bad.