There animals have main steps of nutrition
Answers
Answer: The main steps of nutrition are
Explanation:
- Ingestion
- Digestion
- Absorption
- Assimilation
- Egestion
Animals are divided in to three groups on the basis of their food habits. These are: Herbivores, Carnivores and Omnivores.
Nutrition in Animals
There are five steps in the process of Nutrition in animals. These are: Ingestion, Digestion, Absorption, Assimilation and Egestion.
Ingestion: is the process of taking food in to the body or ‘eating of food’ by the animal. When we put food in to our mouth with hands, we are ingesting it.
Digestion: is the process in which the food containing large, insoluble molecules is broken down in to small, water soluble molecules which can be absorbed by the body or digestion is the dissolving of the solid food. Most of the animals include both physical and chemical methods for digesting the food. Physical method includes chewing and grinding the food in mouth and chemical method include the addition of digestive juices (enzymes) to food by the body itself.
Absorption: is the process in which the digested food passes through the intestinal wall in to blood stream. As, after the digestion, food molecules become small and soluble. This food passes through the walls of our intestine and goes in to the blood.
Assimilation: is the process in which the absorbed food is taken in by the body cells and used for energy, growth and repair. Blood carries the absorbed food to all the parts of the body.
Egestion: is the process in which the undigested food is removed from the body. The whole food which we eat is not digested by our body, a part of the food remains undigested which cannot be used by the body and so it is removed from the body in the form of faeces when we go to the toilet.
Nutrition in Simple Animals
There are two very simple animals namely amoeba and paramecium. They are made up of single cell and so known as unicellular animals. So, all the 5 processes of nutrition are performed by single cell. The mode of nutrition in amoeba is holozoic. They eat tiny or microscopic plants and animals as food which floats in water in which it lives. The process of obtaining food by Amoeba is called phagocytosis means cell feeding.
(i) Ingestion: Amoeba has no mouth so food is ingested by using pseudopodia. When food comes near amoeba, then amoeba ingests this food particle by forming temporary finger like projections called pseudopodia around it. And the engulfed food with water formed a food vacuole which is considered as ‘ Temporary stomach’ of Amoeba.
(ii) Digestion: In Amoeba food is digested in the food vacuole by digestive enzymes. These enzymes break down the food in to small and soluble molecules by chemical reactions.
(iii) Absorption: The digested food present in the food vacuole of Amoeba is absorbed directly in to the cytoplasm by diffusion. Due to the presence of one cell, blood is not required to carry the digested food. The food just spreads out from the food vacuole in to the whole cell of Amoeba and finally food vacuole disappears.
(iv) Assimilation: A part of the absorbed food is used to obtain energy through respiration and the remaining part of the food leads to the growth in Amoeba. And then amoeba can reproduce by dividing in to two daughter cells.
(v) Egestion: Amoeba has no fixed place for removing the undigested part of food.When a considerable amount of undigested food collects inside amoeba, then its cell membrane suddenly ruptures at any place and undigested food is thrown out of the body of Amoeba.
In case of Paramecium, hair like structures called cilia helps to sweep the food particles from water and put them in to mouth. This step is known as ingestion which is followed by other steps such as digestion, absorption etc.
Nutrition in complex multicellular Animals like man, fish, frog etc. all the processes involved in nutrition are performed by a combination of digestive organs. And this combination of digestive organs is called Digestive System which we will be discussing in our next article in details.