Everything that people eat can be followed back to the sun along the food chain. A food chain is a series of organism which interact in a manner that they eat one another consecutively and in the process some nutrients and energy are transferred to the eater. Almost all the food people eat derives their origin from agricultural ecosystems which are controlled by human beings. For instance, people eat meat from cows which also derives its source of food from corn maize and corn maize also receives the light as a source of energy from the sun. In the recent past, there has been a rising issues of biofuel use as a threat to energy flow in human ecosystem. The claims are viable according to my perspective and I support the United Nation food summit to give verdict of the use of biofuel.
Food chain system can either be human controlled or natural .Both the food chains exhibit the flow of energy and nutrients. In natural food chain it is not human controlled. For instance, the hawk may feed on snake and snake may have eaten rat and this rat may also have derived its energy from ground nut or corn maize seed which is obtained from plants. Plant uses energy from the sun to manufacture food. It indicates that every food chain must derive its source of energy from the sun (Cited in Keep energy education, 2002).
Food chain has been classified into two. There are producers which refer to the organisms that manufacture their own food like the green plant. Green plants uses light from the sun known as solar energy and convert it into chemical energy. Water and chlorophyll in presence of chemical energy from the sun enable green plants to manufacture their own food.
In the energy flow the amount of energy that producer receives from the sun is greater than the amount of energy received by the subsequent herbivorous. This show that there is loss of energy along the food chain as you moves from the producer to omnivorous. This energy loss comes due to the fact that the eater my not have completely fed on the plant or the prey. It also comes as a result of some part of the plant or the pray being fed on is not properly digested and utilized thus are excreted as waste products. The second law of thermodynamics also explains the reason behind the decrease in amount of energy along the food chain. This is because some energy was already utilized by the first eater for growth, development, reproduction and locomotion. It was estimated that about ten percent of the total energy that organism received is transferred to the subsequent level of the food chain (Cited in Chapter 6 pp 136, pp126)
Despite energy loss along the food chain the amount of energy in an organism must be adequate enough to cater for the loss, energy requirement for sustaining organism and energy to be passed to the next level of the food chain. This therefore means that the total organic matter or biomass of the producer must be more than the total biomass of the herbivorous and the total biomass for the herbivore must also be larger than the total biomass of carnivores. This brings to a conclusion that the number of producers is larger than the number the number of consumer. The amount of undigested and unconsumed organic material then undergoes a decomposition process. In this processes there are a number of organism known as decomposers. Examples of decomposers include bacteria, fungi, ants and worms. These decomposer help in recycling nutrients back into the food chain where as some energy are released in form of heat. Food chain is therefore an integral part of the ecosystem in which nutrients are recycled as well as providing an effective flow of energy (Cited in MCkinney, Michael, and Schoch 75-84)
This is where energy flows occurs, and it combines a biological community which is interacting with each other as well as their chemical and physical environment. An ecosystem can either be too large or too small. Species plants or animals can interact through pollination, predation or mutual relationship. Animals and plants can also interact in ways such as birds and insects help in plant pollination and animals may also use plants as food. Plant and animals may also interact with non living matter through processes like photosynthesis, respiration and even evaporation (Cited in Chapter 6 pp 125-127)
Current News on biofuel problems in energy flow and food security. There has been an endless meeting for the great eight and great twenty nations and currently the United Nation have organized another food summit to be held in mid November 2009 immediately after the same summit which was held in 2008. The disturbing question is why so soon after a similar meeting was held in 2008. The UN Food and Agriculture Organization is the host of the food summit. Food summit is also expected to fall into the category of financial summit of the great twenty nations which was held in London. The president of the International Funds for Agricultural development claimed that the summit is going to be a successful one. One of the agenda for discussion is the issue of Biofuels which has been establishing base in most of the developed countries. It is said to be a threat to food production because it compete for land which would otherwise be used for food production. It is claimed that this competition will lead to increase in food prices because of interchanging of food and energy. Increase in energy price will lead to high prices of biofuels. The summit is therefore expected to give verdicts on biofuels which is an opportunity and the same pose challenges to the ecosystem and food security. In the environment perspective the incident of biofuel is affecting human ecosystem as well as bring environmental problems such as increase in the green house gases into the atmosphere(cited inEric, Reguly, October 39, 2009).
In the current world most discussion is based on the external use of energy. Most of the activities being done are geared toward energy production for external use. For instance the production of fossil and geothermal energy for the use in the transport industry as well as in the industrial plants. This means that people have diverted their attentions from the internal need of energy by human beings and all the living organisms. Currently there is much interest being put on biomass as an external source of energy as a fuel to be used in residential or industrial plants. The best example is the use of corn based ethanol for transport industry in the United States. This has actually brought about the competition between agriculture aiming at food production and agriculture aiming at production of fuel. This has led to high prices of corn due to competition for the supply between ethanol and food industry. Due to the fact that industrial agriculture needs to expand to be able to cater for both external and internal energy supply for the fast growing world population and the increasing living standards, there is need to expand the availability of agricultural land, water for irrigation, fuel for mechanization, fertilizers for crops and pesticides to control pest and diseases in the farms. This competition is affecting the ecosystem in several ways. For First, plants as primary producers utilizing chemical energy from the sun to manufacture food which will further be required by the subsequent consumers in the food chain.