2.2.1—Ecosystem sustenance
- Syllabus
- First assessment 2026
- Objective
- 2.2.1
- Level
- HL
Ecosystems Need Energy In and Matter Moving
Energy must be continually supplied, while matter enters, leaves and can be reused through cycles.
Sunlight or chemical energy enters and heat leaves; water, gases, nutrients and organisms cross the boundary. Matter cycling does not make an ecosystem closed.
A pond receives sunlight and dissolved nutrients, returns heat, and exchanges water and organisms with its surroundings.
Energy, because usable energy disperses as heat; matter can be recycled.
Energy is not recycled in the same way as nutrients.