Question

Answer the following questions in your own words. Explain the various steps of nutrition in animals.

Answer 1

Hint: As we know that nutrition is an essential mechanism in an organism. As important as the bodily movements, breathing mechanism, excretion process etc. it provides energy to the body in the form of food. There are various steps in the nutrition process known as modes of nutrition, where we study about the steps or forms by which animals’ uptake food. Nutrition can be achieved by both direct or indirect ingestion. We will discuss them one on one.

Complete answer:
The answer is animals or higher organisms or in fact lower organisms like protists, euglenoids or amoeba every organism requires food to meet their daily requirements of the body, to maintain life in short. As the majority of energy living beings get from food it is important to know how much of the quantity they require. In food there are also forms such as- carbohydrates, proteins, fats, vitamins, minerals etc. they are required for the maintenance of the body. Nutrition also helps in repairing cells of the body producing new cells or growth of the body.
The five steps of nutrition in animals include ingestion, absorption, assimilation, digestion catabolism and excretion.
a) Ingestion- ingestion is the process of taking in food through the mouth. It is the first and simpler step of nutrition. In higher animals like human being and others the teeth, saliva, tongue play important role and chew the food into bolus (bolus is the grinded food particles ready to be swallowed); chewing of food is also known as mastication. The enzymes present in saliva begin to chemically process the food.
b) Absorption- it describes a way of obtaining energy and nutrients in which digestive enzymes are secreted as substrate and easily assimilated through the cell membrane. This is the second type of nutrition. This process is normally carried out by fungi. It is a way of breaking complex compounds into simpler ones by hydrolytic enzymes.
c) Assimilation- it is the third step of the nutrition process. Assimilation is the movement of digested food molecules into the cells of the body where they can be used. For example, body prepared glucose and glucose is used in respiration to provide energy, similarly amino acids are being produced which builds proteins.
d) Digestion- digestion as we all know about this process it is the breaking down of particles called bolus which passes through esophagus and reaches the stomach. Before mixing into the blood and blood carries the nutrients for cell growth, cell repair and other things.
e) Excretion- this is the last step in the nutrition process. The indigestible compounds which are cannot be absorbed, digested passes through the anal opening of animals. This step of passing out the unwanted materials from the body is called excretion.

Note:
As we discussed all the steps in nutrition how it helps in body building and maintaining life. Animals also take food by autotrophic, heterotrophic, saprotrophic nutrition. They are the modes of nutrition. Autotrophic are animals which feed on plant and plant products such as herbivores. Hetero nutrition is animals which feed on both plant products as well as other animals like carnivores. And saprotrophic nutrition is the animals which live on feeding dead and decaying matter like fungi or bacteria.