What are the 7 major ecosystems?

1. Forest Ecosystems – includes plants, animals and microorganisms that live in coordination with the abiotic factors of the environment
2. Grassland Ecosystems – the vegetation is dominated by grasses and herbs such as temperate, savanna, etc.
3. Tundra Ecosystems – devoid of trees and are found in cold climates or where rainfall is scarce. The ecosystem in the Arctic or mountain tops is tundra type
4. Desert Ecosystem – found throughout the world. These are regions with very little rainfall
5. Freshwater Ecosystem – includes lakes, ponds, rivers, streams and wetlands.
6. Marine Ecosystem – includes seas and oceans.

Further Readings – 

1. Coral reef
2. Great Indian Desert | Thar Desert
3. Tropical RainForest