Nutrition in Living Organisms

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Nutrition is the essential organic nutrients living organisms require for growth, maintenance, reproduction and repair. This is an essential process for the organism’s survival. Living organisms require energy to survive; this energy is derived from nutrients, or food. Ingestion, digestion, absorption and excretion are the stages of processing food. Heterotrophs are organisms which cannot synthesise their own food and are therefore totally reliant on organic substances for nutrition. Animals are heterotrophs and are divided into three categories; herbivores, carnivores and omnivores depending on how they obtain their food. Herbivores: eat mainly plant material, seeds or fruit. (Gordon McL Dryden, 2008). Omnivores: eat both vegetable and animal material. Carnivores: eat meat (they can also eat insects and fish).Plants are autotrophs, they synthesise organic substances from inorganic molecule using sunlight energy.

All animals, fungi, most protists and prokaryotes are heterotrophs (Raven et al. 2009), animals which cannot live on inorganic nutrients alone. They obtain the organic nutrients they require from the products of photosynthesis produced by autotrophs. The ability of an animal to feed itself is closely related to its reproductive success. According to (http://en.wikipedia.org/wiki/Nutrition (3/3/11, 12:44)) there are six main classes of nutrients required by animals. These nutrients are either macronutrients (high quantities required) or micronutrients (small quantities required). The macronutrients include carbohydrates, fats, protein, and water. The micronutrients are mainly minerals and vitamins.

Many nutrients and vitamins which animals need to survive cannot be synthesised and must be supplied in the diet, these nut...

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...rganic sources; Broomrapes are parasitic plants, they are non photosynthetic and obtain water and all required nutrients from the root of their host plants.

In conclusion living organisms require many nutrients. These nutrients are required to ensure energy is available for growth, maintenance, reproduction and repair. Some nutrients are needed in high amounts whereas others only in low amounts. All living organisms require different nutrients for survival however if heterotrophs or autotrophs lack essential nutrients and cannot obtain these in their diet they will show signs of deficiency and eventually die.

Works Cited

Animal nutrition science (Gordon McL Dryden, 2008)

Biology (Raven et al. 2009)

http://en.wikipedia.org/wiki/Nutrition (3/3/11, 12:44)

New Higher Biology (J Torrance, C Stevenson, J Fullarton, C Marsh, J Simms 2nd Revised edition,2000)

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