• Ecosystems

• Biomass
• Biomes
• Biosphere reserves

• Atmosphere
• Biogeography
• Earth (planet)
• Ecology
• Habitats
• Human activities effects
• Human species
• Hydrosphere
• Natural environment

• That part of the earth, and the atmosphere surrounding it, which is able to support life.

• Science > Natural resources

http://vocabularies.unesco.org/thesaurus/concept3277