Food and Human Life Cycle

Foodand Human Life Cycle

Foodand Human Life Cycle

PartA: Food and Energy

Fooddefined as any substance that once consumed it can provide energy tothe body and other support. Food originates from both animals andplants and is grouped into various essentials that include fats,carbohydrates, vitamins, proteins and minerals. The food substancesare absorbed and ingested into the body of an organism to produceenergy and maintain life to facilitate growth. In the past peopleused to get food through hunting and gathering but now people getfood energy from the food industries (Stephen, 2009). Food is notconsumed by only animals but all living things exist because of food.Food is very crucial for the live of an organism and it is throughfood that organisms get energy.

Photo1: An experiment carried at home on burning calories (a mushroom wasused)

Foodcomes from different things that an organism consumes the food has abasic nutrient that is required to perform different functions.Plants depend on sunlight, water and carbon dioxide to make food. Itis important to learn that sunlight is a great source of energybecause it is necessary for converting the nutrients of the plant toenergy and oxygen (Guyton, 2011). The food eaten by an organismperforms its duty and it is disintegrated to different components.

Photo2: Showing a leaf

Theleaf is important to these plants because it is necessary forphotosynthesis whereby plants make their own food. The food createdis used in providing energy to the plant. Once an organism takes infood the enzymes act on the food and they make it useful for theorganism. The organism converts food to the required energy and theother waste products that result from food is excreted from the body.Plants and animals interrelate because the waste products that comefrom animals is used by the plant to form food (Jeffrey, 2010).Carbon dioxide is the waste product that comes from animals but it isused by the plant as a component in creating food. Living organismsuse oxygen that is the waste product from the plants.

Photo3: Showing an experiment of burning calories in a lab

Thephoto shows how animals lose their weight and matter, by burning thefood substance in the boiling tube the food substance disintegrates.Animals lose weight when they are faced with a number ofcircumstances, which necessitate them to strain. When the bodyoverstrains it losses more weight and mass. The big bodied peoplelose their weight without noticing where the mass of the body went.The answer is quite simple bodies convert molecules present in thefat cells to usable energy that makes the cells to shrink. For thisto happen, the body is responsible in converting the calories topotential energy that is used by the body. Weight loss occurs throughthe burning down of the calories. The calories are the measure ofenergy in the body which is in the form of carbohydrates, proteinsand fats (Guyton, 2011). The bodies of animals work like theelectromotive and the gas that keeps the electromotive to move is theenergy that comes from food in the case of animals. When the body isin a high exercise the energy used is at the maximum and when thebody is at the rest it uses less energy. Some of the calories in thebody are used to digest food. Once food reaches the body it is brokendown to different parts that include carbohydrates, fats andproteins, the remaining energy is either used in the body to storefats (Carpenterand Finley, 2005). When animals lose weight, thecalories are burnt because the body uses excess calories that arestored in the body.

Farmingand ecosystem are among the things that contribute to weight loss.People use a lot of energy while cultivating the farm to grow crops,the energy used in farming is as a result of the calories that are inthe body. The ecosystem also contributes to the lose energy from thebody. The human body losses energy to the environment when anindividual does work that requires energy. It is important to notethat nature cannot be created nor can it be destroyed.

Energyoriginates from the sun and it is distributed to the plants andanimals. The sun provides the required energy that is used inconverting carbohydrates and carbon dioxide to energy. The energyfrom the sun is used in different forms by human beings and plants(Neil, 2010). The chemical energy that is generated through thechemical reaction that occurs on the leaves of the plants is used inthe activities of the plant (Stephen, 2009). The chemical energyturns to work energy when it is operational in the plant throughgetting water from the roots to the leaves and also transporting thefood created on the leaves to all parts of the body. Plants alsoutilize energy like human beings but to a smaller extent. Humanbeings use more energy while walking, working and when doing otheractivities.

Figure1: Showing the food chain and the energy used

Asthere is an increase of energy loss as the level of the food chainincreases because most of the animals in the higher food chain usemore energy to get food. Plants which are the lowest group in thefood chain use less energy in preparing food because it requireswater, carbon dioxide and sunlight to make food by their own (Neil,2010). Human beings who are among the highest level of the food webused more energy to get food and also they have a higher respirationrate.

Figure2: Showing the energy levels in the food chain

Thechemical equations for photosynthesis and respiration in animals area clear indication of how weight is lost. The cells of humans areformed by different components and their size is determined by theturgidity level or the fat that surrounds the cell. Big bodied peoplehave more calories that are in form of fats that are in the cells.When there is a high rate of respiration in the body the cellrequires more energy and this energy is derived from the fats thatare in the cells. The mass that is in the body disintegrates to formthe required energy for respiration (Stephen, 2009). The choice offood depends on the quality of matter that is contained in the food.High quantities of matter provide more energy to humans compared tolow quantities of matter.

PartB: Reflection Paper

Thestudy has helped a lot in determining the origin of energy in plantsand living organisms. I have gained in knowing that the food thatorganisms take is the sole source of energy in the bodies and thatall the organisms require energy for proper operation. Human bodiesutilize energy through very many ways, which include working,respiration, digestion, and many others. Energy lost while working isnot reversible but it can be regained back through food, this makesfood to be the most important component in the life of a human being(Jeffrey, 2010).

Ihave noted that the sun is the sole source of energy to theecosystem. Most of the creatures depend on the sun for energy. Takingthe instance of a food chain with the primary level of plants theplants use sunshine to create food and the food is used in the plant.The food made by the plants is taken by the secondary consumers thatuse this food for energy and for making food for the tertiaryconsumer (Ross, 2010). The food chain clearly shows the sun is thesource of energy and it is the basic need for plants to make food.

Throughthe study, I have learnt that energy cannot be constructed nor can itbe destroyed. The energy that is in the body of a human being cannotbe generated but can be conserved through measures of eating healthfood. Proper conservation of energy leads to stabilization in thebody and proper operation of all the human functions. I haveunderstood that the energy in the human body is not created whenpeople take food but it is conserved to keep the body at equilibrium.

Ihave understood the concept of utilization of energy in the humanbody better than before. The body of a living being functionssimilarly likes a vehicle or other electromotive. When there is nofuel in the electromotive there is no movement similarly when thereis no energy in the human body there is no-work done because the bodydepends on energy to function well (Jeffrey, 2010).

Inconclusion, food is very essential in the life of an organisms andfood gives energy to the organisms. The sun plays a crucial role inthe ecosystem because it is the primary source of energy that isrequired by the lower level of the food chain to make food thatsustains the life of the subsequent members in the food chain. Theexercise has helped to put emphasis on the work of energy in theecosystem.


Carpenter,R., and Finley, E. (2005) HealthyEating Every Day.(6thEd). New York: LynneRienner Publishers

Guyton,J. (2011)Introductionto Human Health.Textbookof medical physiology 11ed p. 887 Elsevier Saunders

JeffreyS. F. (2010). Regulating Energy Balance: The Substrate Strikes Back.Science Press Inc,.p861-864.

Neil,C. (2010). Food and Physiologyof Behavior of an Individual.Boston, MA: Allyn&amp Bacon Publishers. pp.&nbsp412–426

Ross,K. A. (2010) Energy and fuel, in Littledyke M., Ross K. A. and LakinE. (eds), Science Knowledge and the Environment. London: David FultonPublishers

StephenS. (2009) Efficiency,Economy and Endurance Performance,(2ndEd.). San Francisco: Bass Publishers