The document defines an ecosystem as the basic functional unit of ecology, consisting of interacting organisms and their environment. It notes that ecosystems have biotic components including producers like plants, consumers like herbivores and carnivores, and decomposers like microbes. Abiotic components include physical and chemical factors like sunlight, water, minerals and temperature. Food chains within an ecosystem are interconnected to form a food web. Energy is transferred and transformed between trophic levels from producers to consumers to decomposers. Factors like population growth, industrialization, deforestation and pollution can impact ecosystem balance and health.