Glossary of "Ecology (6th ed.)" by Krebs (2009)
- all the processes through which natural ecosystems and the biodiversity they contain help sustain human life on Earth.
Glossary of "Plant Biology (1st ed.)" by Graham et al. (2003)
- Services provided by the operation of ecosystems such as soil formation and enrichment, water purification, oxygen production and carbon dioxide storage, nitrogen fixation, temperature control, and crop pollination.
Glossary of "Life (9th ed.)" by Sadava et al. (2011)
- Processes by which ecosystems maintain resources that benefit human society.
- Graham, L. E., Graham, J. M. & Wilcox, L. W. 2003. Plant Biology. -xxxv + 497 pp. Pearson Education, Inc., Upper Saddle River.
- Krebs, C. J. 2009. Ecology, 6th ed. -xvi + 655 pp. Pearson Benjamin Cummings, San Francisco.
- Sadava, D., Hillis, D. M., Heller, H. C. & Berenbaum, M. R. 2011. Life: The Science of Biology, 9th ed. -xliv + 1266 pp. Sinauer Associates, Inc., Sunderland.