Biology

Animals and plants are living things that depend with each other for survival. Plants manufacture their food through photosynthesis while animals depend on plants for their food. In order for plants to manufacture food, they require carbon dioxide, sunlight and water, (Silverstein, Silverstein  Nunn, 2007). This paper shall therefore describe the process of photosynthesis and how animals benefit from the process of photosynthesis and also demonstrate that without plants, animals including human beings cannot survive.

Background Information
    Photosynthesis is a process through which plants manufacture their own food by use of carbon dioxide, energy from the sun and water. According to Rao  Hall (1999), the process of photosynthesis occurs in the chloroplasts. Chloroplasts contain chlorophyll which is able to take the energy from the sun. Carbon dioxide combines with water and in the presence of sunlight plants manufacture carbohydrates and also release oxygen.

However, carbohydrates need to be further broken down through a process of cellular respiration in order to form energy that can be used by plants. This takes place in the cell mitochondria in the presence of oxygen. The products of this process are water, carbon dioxide and energy.  On the other hand, animals depend on oxygen gas and carbohydrates for survival. During respiration, animals take in oxygen and release carbon dioxide while plants take in carbon dioxide and release oxygen.

How People Benefit from Plants
As indicated by Rao  Hall (1999), animals do not make their own food. They depend mainly on carbohydrates manufactured by plants in the process of photosynthesis. Animals require this energy to carry out their activities in the body. Oxygen released by plants during the process of photosynthesis is also a vital gas for the survival of animals. Moreover, plants purify the air as they take in carbon dioxide that is released by animals during respiration. Rao  Hall (1999) continue to argue that, were it not for the process of photosynthesis, the atmospheric oxygen can be used up in a period of three thousand years. Therefore, one of the most important functions of photosynthesis is to balance the amount of carbon dioxide, and oxygen in the atmosphere.

Failure of plants to release enough oxygen to the atmosphere is a dangerous phenomenon. It results in excessive carbon dioxide in to the atmosphere. This case was clearly illustrated in the biosphere experiment.  During this experiment, as Day (2005) records, the level of oxygen decreased while the level of carbon dioxide increased. The continued use of oxygen led to its reduction while carbon dioxide released by people during respiration greatly increased in the air. The condition could not be tolerated by people and more oxygen had to be pumped in while air purifiers were used to remove excess carbon dioxide.

    Plants and animals depend on each other for survival. Even with all the conditions needed for survival, none can survive for a very long time without the other. In the case of animals, this was clearly shown in the biosphere experiment in which even before the end of two years, there was so much carbon dioxide in the atmosphere and air purifiers had to be used. Oxygen level in the air went down and more of it had to be pumped in. Likewise, plants cannot survive in an air tight container that has everything expect oxygen. This is mainly because the oxygen released during photosynthesis may increase and interfere with the rate of photosynthesis. Moreover, oxygen is used during the process of cellular respiration by plants.

From this paper, one can conclude that without plants people cannot survive. This is because everything needed by people for survival is primarily from plants. This includes the food as well as the oxygen.