Question

Differentiate between ingestion and egestion.

Answer 1

Hint: The terms both ingestion and egestion are the steps in the process of nutrition in all animals from protozoans to most complex mammals.

Complete answer:
> Ingestion
- Is nothing but the process of intake of food into the body.
- Ingestion is the step which occurs from unicellular animals to most complex animals like mammals.
- In unicellular animals like amoeba and paramecium the whole process of nutrition takes place in a single cell.
- In amoeba, ingestion takes place by the formation of temporary pseudopodia which are finger-like projections.
- In paramecium, there is the presence of tiny hair-like structures called cilia, which intake food particles from the surrounding environment with the help of cilia.
- In complex animals like mammals,the whole process of nutrition takes place in a system called digestive system.
- Whereas intake of food occurs with the help of the mouth.

> Egestion
- Is nothing but elimination of undigested food from out of the body.
- Egestion also takes place from unicellular animals to most complex animals.
- In unicellular animals like amoeba, after the whole process of nutrition, whatever the undigested food that remains will be moved to the surface and eliminated from the body.
- Whereas in other unicellular animals like paramecium the process of egestion is the same as seen in amoeba.
- In complex animals like mammals the process of nutrition takes place in different parts of the digestive system.
- Where after ingestion of food, it travels from mouth to esophagus and stomach and to intestine, where digestion, absorption and assimilation take place in different parts.
- After the whole process of nutrition, the undigested food that remains in the large intestine will be removed from the body through anus.
- The process of egestion through anus in complex animals is regulated by anal sphincter.

Note: Both ingestion and egestion are part of the process of nutrition intake, ingestion means intake, egestion means expel out. Elaborating the both process in unicellular and complex animals will increase the content and quality of the answer.