Keystone Ecology Practice Test 2025 – Comprehensive All-in-One Guide to Exam Success!

The term that describes all life on Earth and all parts of the Earth where life exists is the biosphere. The biosphere encompasses not just the organisms themselves, including plants, animals, fungi, and microorganisms, but also the environments where these organisms interact, such as land, water, and the atmosphere. Essentially, the biosphere is a global ecological system integrating all living beings and their relationships with the elements of the environment.

In contrast, a biome refers to a specific ecological region characterized by particular climate conditions and types of organisms, such as deserts, forests, or grasslands. A population is a group of individuals of the same species living in a specific area, while a community encompasses all the different species living and interacting in a particular area. Thus, while these other terms define smaller components of ecological study, the biosphere represents the comprehensive sum of life and habitats across the planet.