The document provides information about different types of terrestrial ecosystems. It defines terrestrial ecosystems as ecosystems that occur on land, as opposed to aquatic ecosystems. It notes that terrestrial ecosystems make up 28% of the world's area but contain much more variability in flora and fauna compared to aquatic ecosystems. The document then describes the major classifications of terrestrial ecosystems as biogeographic realms and biomes. It provides details on the six biogeographic realms and seven major biomes that characterize different terrestrial regions based on their climate and plant/animal life.