You see them every day. You eat them. You wear them. You live in buildings made of them. In fact, plants, or members of the kingdom Plantae, are found everywhere in the world10, and we simply would not be able to live without them(11). The approximately 250,000 to 380,000 currently-known plant species (2,7,8,11) include two main groups: some of the primarily water-dwelling organisms called green algae (specifically a group known as the charophyte algae12), and the embryophytes or land plants which evolved from green algae (1,12,14). A wider definition of plants that is sometimes used also includes the rest of the green algae as well as other types of algae known as red algae and glaucophyte algae (9,14.). The major subset of plants called land plants is divided into two main groups itself: nonvascular plants (those that don’t have special systems allowing them to transport water and nutrients inside their bodies; these plants include mosses, hornworts, and liverworts(5,7); and vascular plants (those that do have such transport systems; these include some more familiar groups including the largest plant group, the flowering plants(14). While all organisms are made up of cells, plants have a special wall around each of their cells built out of a carbohydrate called cellulose (7) that makes them especially strong and firm (6). Unlike most other forms of life, most plants produce their own food through a complicated process called photosynthesis (9), in which they soak up sunlight, usually with their leaves, and use it to turn carbon dioxide combined with water into energy-rich sugars (3,15). Through this process, plants have an extremely important effect on the environment and the climate—they remove carbon dioxide, a gas that contributes to global warming, from the air (13), and at the same time release oxygen, which is essential to the survival of animals, plants, protists, and many bacteria (3,4,15). Plants also provide food and shelter for many kinds of organisms, and we humans rely on them directly for grains, vegetables, fruits, wood, paper, clothing, and many medicines (8,11). In the future, they may be useful as sources for new medicines (8) and other products (6), as well as for emerging fuels that are renewable and more environmentally-friendly (6). For all of these reasons and more, it is vital that we protect plants around the world (2,8,11).
- 1. Becker, Burkhard and Birger Marin. “Streptophyte Algae and the Origin of Embryophytes.” Annals of Botany 103.7 (2009): 999-1004.
- 2. Brummitt, Neil, Steven P. Bachman, and Justin Moat. “Applications of the IUCN Red List: Towards a Global Barometer for Plant Diversity.” Endangered Species Research 6 (2008):127-135.
- 3. Carter, J. Stein. “Photosynthesis.” 2004. 20 Jun. 2011. http://biology.clc.uc.edu/courses/bio104/photosyn.htm
- 4. “Chapter 8 How Cells Harvest Energy from Food.” Lambuth University. 1 Aug. 2011.
- 5. Charron, Audra J. and Ralph S. Quatrano. “Between a Rock and a Dry Place: The Water-Stressed Moss.” Molecular Plant 2.3 (2009): 478-486.
- 6. Doblin, Monika S., Filomena Pettolino, and Antony Bacic. “Plant Cell Walls: The Skeleton of the Plant World.” Functional Plant Biology 37.5 (2010): 357 -381.
- 7. Farabee, M. J. “Biological Diversity: Nonvascular Plants and Nonseed Vascular Plants.” 2004. 29 Jun. 2011. http://www2.estrellamountain.edu/faculty/farabee/biobk/BioBookDiversity_5.html
- 8. “Green Medicine.” Plant Conservation Alliance – Medicinal Plant Working Group. 2011. 1 Aug. 2011. http://www.nps.gov/plants/medicinal/
- 9. Keeling, Patrick J. “Diversity and Evolutionary History of Plastids and Their Hosts.” American Journal of Botany 91.10 (2004): 1481-1493.
- 10. Kier, Gerold, Jens Mutke, Eric Dinerstein, Taylor H. Ricketts, Wolfgang Küper, Holger Kreft, and Wilhelm Barthlott. “Global Patterns of Plant Diversity and Floristic Knowledge.” Journal of Biogeography 32 (2005): 1107–1116.
- 11. Lane, Meredith. “Plant.” AccessScience. McGraw-Hill. 2008. 20 Jun. 2011. http://proxy.montgomerylibrary.org:2165/content/Plant/522400
- 12. Lewis, Louise A. and Richard M. McCourt. “Green Algae and the Origin of Land Plants.” American Journal of Botany 91.10 (2004): 1535-1556.
- 13. Loreto, Francesco and Mauro Centritto. “Leaf Carbon Assimilation in a Water-Limited World.” Plant Biosystems 142.1 (2008): 154-161.
- 14. Palmer, Jeffrey D., Douglas E. Soltis, and Mark W. Chase. “The Plant Tree of Life: An Overview and Some Points of View.” American Journal of Botany 91.10 (2004): 1437-1445.
- 15. Robertson, Bill. “Q: How Does Photosynthesis Work?” Science 101: Background Boosters for Elementary Teachers. National Science Teachers Association. 2006. 20 Jun. 2011.
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