Introduction 

Holozoic nutrition refers to the process of nutrition in which different steps of nutrition are involved. In holozoic mode of nutrition, the food intake of complex food material is undertaken by the animal. It is a method of food intake by the organisms through the mouth. The food further progresses to the digestive system. The preeminent example of holozoic nutrition is human beings. The holozoic nutrition process involves breaking down food into various small parts and processing it to derive nutritious elements. The complete process is done to separate the essential parts required for the growth of the body and waste materials from the excretion system.

Holozoic nutrition: overview

The term holozoic is derived from the Greek word holo, which means whole, and zoikos, which means animals. The study on holozoic nutrition is based on the nutrition process in animals. Holozoic nutrition is the heterotrophic mode of nutrition. This type of nutrition involves a process of internalisation and further includes an internal process in the stomach of the animals. Holozoic nutrition contains the processing of solid food particles as well as liquid foods and breaks them into nutritious and insubstantial elements. Protozoa exhibit this type of nutrition and are mostly found in the amoeba. Human beings also derive their food through holozoic nutrition, where the solid or liquid food is taken through the mouth and further breakdown of the food is processed inside the body of the animals. 

Holozoic nutrition: Types 

Holozoic nutrition is derived from the animals and organisms by the internalisation or ingestion method. The animal’s that acquire their food using holozoic nutrition are called holozoic organisms. It is divided into three parts: herbivores, carnivores and omnivores.

Herbivores: herbivores are the animals that derive their foods from plants. The primary source of nutrition in these animals is based on plants and trees. Examples of herbivores can be understood by the vertebrates such as koalas, deer and various types of species of birds. Invertebrates also derive their nutrition under the category of herbivores such as caterpillars and crickets. The digestive system has evolved in this type of organism. It is further classified into folivores, nectivores, granivores, and frugivores.

Carnivores: carnivores are those types of animals that acquire their food and nutrition by eating other animals. “Carnivore” is derived from the Latin word which means “meat-eater”. Examples of carnivorous animals are wild cats, sharks, snakes and others.

Omnivores: in Latin, the word omnivore means who eats everything”. The prominent example of omnivores is the human being. Omnivore animals come from both vertebrates and invertebrates. The nutrition derived from this type of holozoic method is crucial and can be witnessed in different animals such as humans, crayfish, cockroaches, bears and others.

Process of holozoic nutrition: 

• Ingestion: intake of the complex food by the animals through the mouth is known as the ingestion process. 
• Digestion: the food particles intake by ingestion is further broken down into smaller particles with the help of a digestion system. 
• Absorption process results in absorption of the valuable nutrients from the food by the body. 
• Assimilation: assimilation process includes the making of material utilizing the nutrients derived from the process of absorption.
• Excretion: This is a significant step of the holozoic nutrition process, in this system the waste materials derived from all the processes are flushed outside the body.

Conclusion 

Holozoic nutrition is a significant part of heterotrophic nutrition and involves internal processes of digestion and egestion. The process involves different steps such as indigestion, absorption and assimilation. The concept of holozoic nutrition varies from the concept of halophytic nutrition. In halophytic nutrition, food and nutrition are derived by the plants using photosynthesis. In holozoic nutrition, the separation of food particles and waste material is done by an excretion system. The process of digestion, ingestion, egestion and excretion are crucial in completing the breakdown process of food particles. This process is known as the holozoic process