Adaptation Of Plants

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Adaptation of Land Plants The plants that we know today as terrestrial organisms were not always on land. The land plants of today can be linked back to aquatic organisms that existed millions of years ago. In fact, early fossil evidence shows that the earliest land plants could have arisen some 450 million years ago (Weng & Chappie 2010). Plants that used to reside strictly in water were able to adapt in ways that allowed them to move onto land. It is speculated the need for plants to move onto land was created by water drying up, causing plants to have less room and pushing them to move onto land. Although the exact cause of plant’s need to move to a terrestrial environment is unclear, it is known that plants had to undergo several adaptations to be able to live on land. These adaptations include: lignin, cellulose, suberin, and changes to plant’s surface, including the formation of a waxy cuticle. Lignin is one of the key elements that allowed for plants to be able to evolve to a point where they were able to survive on land. Lignin is a macromolecule that serves to bind cellulose together and create strong structural support for plants. A plant’s ability to grow is especially limited by their strength, making lignin crucial for vascular plants. Plants lacking lignin are often non-vascular, and are less evolved than those plants with lignin present. Without lignin land plants would not be able to stand upright, which would interfere with many things necessary to plant growth, such as the conduction of sunlight as well as shade avoidance, or being able to grow out of lightless areas. Aside from lignin’s obvious strengthening purpose it can also help plants in other ways. For instance, lignin contains specialized water conduct... ... middle of paper ... ...ulose will be protected from anything that could potentially damage the cell otherwise. It also plays a part in helping cells keep their shape. Cell walls, along with cellulose, provide support for plants so that they can grow tall while maintaining their shape. The size of the plant will determine the amount of cellulose it will need, but all plants require some amount of it and make use of it constantly. Plants also had to adapt on the surface in order to survive the climate change of moving onto land. The changes made to the surface of plants are most closely observed by their formation of a cuticular wax. This waxy cuticle is impermeable to water and acts as a method of controlling plant’s water intake. It can be made thinner or thicker depending on the plant’s needs and the environment at the time, changing in response to droughts or excessive amounts of rain.

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