A heterotrophic organism can obtain its food from other organisms in following three ways:
- Holozoic nutrition
- Saprophytic nutrition
- Parasitic nutrition
Holozoic nutrition takes place in those organisms which take solid or liquid food through the mouth inside their body Examples of organisms having holozoic mode of nutrition are human beings, dog, cat, lion, deer, crow, frog and fish etc. This process takes place in following steps:
The process of taking food inside the body is called ingestion.
In digestion the ingested food is converted into simple form with the help of digestive enzymes.
In this stage the food digested in second step is absorbed into the cells of body.
Assimilation is the process of utilizing the food absorbed in third step by various cells of the body.
Egestion is the final step of holozoic nutrition in which the undigested food is removed from the body.
Test Your Understanding and Answer These Questions:
- Define ingestion.
- What is assimilation?
- Define digestion.
- What is holozoic nutrition? Explain different steps of holozoic nutrition.