Guest Author - Alegra Bartzat
The whole existence of life on earth can be credited to our little green friends. No, I donít believe that martians are responsible for life on earth. Iím talking about plants! Plants are described as autotrophic, meaning they self-feed.
The green pigments in plants (usually concentrated in the leaves but not always) are collectively called chlorophyll. CHLOROPHYLL captures some of the sunlight that hits the plant and converts into a form of energy that the plant can use to grow and survive. In this way, plants create life from non-living materialsÖ Amazing!
Plants also use other pigments to capture sunlight. These other pigments absorb green light and reflect reds, yellows, oranges, and browns. The chlorophyll, which absorbs the reds and reflects the greens, dominates throughout the growing season. But when fall comes and the chlorophyll begins to break down, the other pigments called CAROTENOIDS begin to show themselves.
Some plants use more carotenoids than the chlorophyll, but it is an exception to the rule. Many seaweeds use carotenoids because the green light is the only light than penetrate through deep ocean water, and carotenoids are better at absorbing the green light than chlorophyll.
Plants use carbon dioxide and water as the main source of building blocks for their growth; they create carbohydrates and other essential molecules for their development from the components of carbon dioxide and water: carbon, hydrogen, and oxygen.
Plants use much of the energy the capture from the sun for growing foliage and developing flowers, seeds, and sometimes fruit. But plants can also store some of that energy. Tubers, rhizomes, bulbs, and even roots and fruits can be used to store the plantís energy. Examples are potatoes, carrots, onions, beans, and of course many fruits. This makes those plants parts attractive as a food source to other animals, because the plant has done all the work storing the energy and then the animal can get a big meal.
The leaves are usually the most important part of a plant for capturing sunlight, but the leaves also exchange oxygen and carbon dioxide into and out of the atmosphere. This occurs through small holes in the underside of the leaves called STOMATA. In most plants, these open during the day to release oxygen and even water while absorbing carbon dioxide. Cactus and a few other plants use a different system, opening stomata at night to prevent water loss, and therefore limited to slower growth than most plants.
The entire foundation of life comes from plants, and before that, the sun. Primary consumers are herbivorous animals that feed exclusively on the plants, and from there you enter the complex food web, with animals varyingly eating plants and animals, but none of this would be possible without the plants to take the energy from the sun.