During this Unit, students will perform experiments centered around the investigation of questions pertaining to the relationship between energy, biomass, and number of levels and number of organisms in ecosystems.
Through investigations and models, students will find that energy flow through an ecosystem is unidirectional. Students will learn that the decrease in energy as it progresses through an ecosystem is mirrored by a decrease in biomass as it, progresses through an ecosystem. Students will also discover that the amount of light energy that initially enters the ecosystem through photosynthesis ultimately determines the amount of energy available to the remaining levels of the ecosystem.
Students will also explore the efficiency of energy transfer between levels of an ecosystem by comparing oxygen use by a live herbivore and a dead herbivore. Students will discover that one of the main reasons energy transfer between ecosystem levels is inefficient is that organisms must use some of the energy they consume to live. Therefore, not all of the energy that is consumed by an animal or created by a plant is stored as biomass and cannot be passed on to the next level of the ecosystem.
Conceptual Themes addressed in this Unit:
- Systems
- Changes and Reactions
- Energy