Nutrition in Living Organisms Essay

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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 …show more content…
2009). Many vertebrates cannot make at least one of the 20 amino acids. These essential amino acids must also be obtained in the diet. If the animal lacks any of these essential nutrients it will show signs of deficiency.
There are four types of Feeding Mechanisms by heterotrophs this is often decided by the environment they live in; filter feeders feed by staining nutritious food particles from water using a specialised filter e.g. whale and oyster; substrate feeders live in or on the food which they eat e.g. caterpillar on leaf and earthworm in soil; fluid feeders feed on the fluid of other organisms e.g. female mosquito’s feed on the blood of other animals (including humans) by piercing the skin, insert a tube into the flesh to provide her eggs with the essential nutrients. Bulk feeders e.g. most animals including humans eat large pieces of food to obtain the nutrients they require.
For an animal to process food, its body must provide a suitable environment which is favorable to the action of digestive enzymes contained in an area where these enzymes will not attack the body’s macromolecules. Digestion occurs in different areas of the body depending on the animal itself.
Protozoa’s have digestive vacuoles, these are the simplest digestive compartments, where lysosome enzymes are released which breakdown and digest food. Simple animals such as
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