Without decomposers and healthy soils, nutrients would remain locked inside dead material, plant growth would stop, and food webs would collapse.

Understanding ecosystems and biomes helps explain why rainforests flourish near the equator, why deserts form in dry zones, and why tundra dominates polar regions.

Three of the most important cycles for life are the carbon cycle, nitrogen cycle, and water cycle.

Understanding trophic levels explains how energy moves.
Understanding keystone species explains why ecosystems stay balanced (or collapse).

These organisms, called primary producers, form the foundation of ecosystems on land and in water. Without them, there would be no animals, no decomposers, and no energy flow at all.

Understanding how energy moves helps explain why biodiversity matters, why removing one species can ripple across an ecosystem, and how humans fit into the natural world.