Describe the stages of holozoic nutrition with brief examples?

Holozoic nutrition is the process by which animals, including humans, obtain and use food. It takes place in five main stages — ingestion, digestion, absorption, assimilation, and egestion.

When food enters the body (like a human eating an apple), it’s broken down into simpler forms by the digestive system. These nutrients are then absorbed into the bloodstream, used by cells for energy and growth, and finally, any waste is removed from the body.

1. Ingestion

Taking solid or liquid food into the body through an organ like the mouth. Example: A dog eats a piece of kibble.

2. Digestion

Breaking down complex food molecules into simpler, smaller ones using mechanical (chewing) and chemical (enzymes, acids) processes. Example: In the dog’s stomach, digestive acids and enzymes break down the kibble’s proteins into amino acids.

3. Absorption

The digested nutrients move from the digestive tract into the bloodstream or body cells. Example: The amino acids from the digested kibble pass through the dog’s intestinal walls into the blood.

4. Assimilation

The absorbed nutrients are used by cells for energy, growth, and repair. Example: The amino acids help the dog’s body build and repair its muscles.

5. Egestion

Removing undigested or indigestible food materials from the body. Example: The leftover waste from the kibble is excreted as feces.