What term refers to the global sum of all ecosystems?

The term that refers to the global sum of all ecosystems is the biosphere. The biosphere encompasses all regions of Earth that support life, including the land, water, and atmosphere. It includes various ecosystems such as forests, deserts, wetlands, and oceans, where organisms interact with each other and their physical environment.

Understanding the biosphere is fundamental because it highlights the interconnectedness of various ecosystems and the importance of biological diversity. This connection ensures the sustainability of life on Earth, as all biological and ecological processes are interlinked.

Biomes, although related, refer to large geographic biotic units defined by climate, geography, and organisms typical of those regions, rather than the comprehensive concept of the biosphere. A habitat is more specific to the environment where particular species live, and an ecological zone typically refers to specific areas within biomes or habitats characterized by distinct ecological conditions.