This document discusses ecosystems and homeostasis mechanisms. It defines an ecosystem as including all organic life, soil, water, and inorganic components that interact in a habitat. Ecosystems have abiotic components like geography and climate, and biotic components like plants, animals, and microbes. Ecological pyramids graphically represent the trophic structure of an ecosystem in terms of number, biomass, and energy. Homeostasis mechanisms include negative feedback that stabilizes deficiencies and disequilibriums, and positive feedback that can occur from human interference removing population controls. Concluding, the document states that increasing human activities are making ecosystems more fragile, which could impact humans.