Difference Between Holozoic and Holophytic Nutrition

The main difference between holozoic and holophytic nutrition is that in the holozoic nutrition mode, organisms ingest and internally process food particles for their energy and organic building blocks whereas, in the holophytic nutrition mode, organisms obtain energy and organic building blocks through photosynthesis. Furthermore, holozoic nutrition occurs in free-living animals such as humans and protozoans such as amoebas while holophytic nutrition mainly occurs in photoautotrophs.  

Holozoic and holophytic nutrition are two types of nutrition modes in organisms. Generally, they are responsible for providing energy and organic building blocks. 

Key Areas Covered 

1. What is Holozoic Nutrition
     – Definition, Mode of Nutrition, Type of Organisms
2. What is Holophytic Nutrition
     – Definition, Mode of Nutrition, Type of Organisms
3. What are the Similarities Between Holozoic and Holophytic Nutrition
     – Outline of Common Features
4. What is the Difference Between Holozoic and Holophytic Nutrition
     – Comparison of Key Differences

Key Terms 

Autotrophs, Heterotrophs, Holophytic Nutrition, Holotrophs, Holozoic Nutrition, Photosynthesis

Difference Between Holozoic and Holophytic Nutrition - Comparison Summary

What is Holozoic Nutrition 

Holozoic nutrition is a type of nutrition mode in which internalized food particles undergo internal processing. Generally, these food particles consist of complex organic substances, and they are in the form of solids or liquids. Since energy and organic building blocks are obtained from complex organic substances, holozoic nutrition is a type of heterotrophic nutrition mode. Furthermore, holozoic nutrition occurs in higher animals with a complete digestive system as well as in unicellular forms of animals such as protozoans inside their cell.

Main Difference - Holozoic vs Holophytic Nutrition

Figure 1: Holozoic Nutrition in Amoeba

Furthermore, the five phases of holozoic nutrition include ingestion, digestion, absorption, assimilation, and egestion. The ingested food particles undergo digestion to breakdown complex organic substances into simple building blocks by the action of the digestive enzymes. The digestive system produces these enzymes in higher animals while in unicellular protozoans, enzymes occur in lysosomes. Moreover, in higher animals, these simple substances are absorbed and assimilated by the body through the wall of the digestive system. Ultimately, the indigested materials eliminate from the body through egestion.  

What is Holophytic Nutrition 

Holozoic nutrition is a type of nutrition mode in which organic building blocks and energy are synthesized through photosynthesis. Therefore, it is a type of autotrophic nutrition mode that occurs in plants. Generally, the energy from sunlight is trapped by the photosystems in chloroplasts; ultimately, this energy is fixed in simple organic substances such as glucose. However, the carbon source of glucose is inorganic carbon obtained in the form of gas. Therefore, plants are photoautotrophs.

Difference Between Holozoic and Holophytic Nutrition

Figure 2: Modes of Nutrition

Moreover, chemoautotrophs that undergo chemosynthesis are not holophytes, although they synthesize simple organic compounds through chemosynthesis by using inorganic carbon sources. On the other hand, there is another nutrition mode called holotropic nutrition mode. Heterotrophs that are neither saprotrophs nor parasitic are holotrophs. However, the nutrition mode of holotrophs is holozoic nutrition. 

Similarities Between Holozoic and Holophytic Nutrition  

  • Holozoic and holophytic nutrition are two types of nutrition modes found in organisms.  
  • These modes describe the way through which organisms obtain energy and organic building blocks.    
  • Both unicellular and multicellular organisms undergo these types of nutrition modes. 

Difference Between Holozoic and Holophytic Nutrition 

Definition 

Holozoic nutrition refers to a nutrition mode in which energy and organic building blocks are obtained through the internalization of food particles followed by the internal processing while holophytic nutrition refers to a nutrition mode in which energy and organic building blocks are obtained through photosynthesis. 

Significance 

Another major difference between holozoic and holophytic nutrition is that holozoic nutrition occurs in animals, while holophytic nutrition occurs in plants. 

Occurrence 

Holozoic nutrition occurs in free-living animals such as humans and protozoans such as amoebas while holophytic nutrition mainly occurs in photoautotrophs.  

Intake of Nutrients 

In holozoic nutrition, organisms take in complex organic substances in the form of solids or liquids while in the holophytic nutrition, organisms take in simple inorganic substances in the form of liquids or gases. 

Phases 

The five phases of holozoic nutrition are ingestion, digestion, absorption, assimilation, and egestion, while the two phases of holophytic nutrition are synthesis and assimilation. 

Digestive System 

Organisms with holozoic nutrition have a well-developed digestive system while organisms with holophytic nutrition lack a digestive system.  

Requirement of Sunlight 

Organisms with holozoic nutrition do not require sunlight, while organisms with holophytic nutrition require sunlight. 

Type of Nutrition 

Moreover, holozoic nutrition is a type of heterotrophic nutrition, while holophytic nutrition is a type of autotrophic nutrition. 

Type of Organisms 

Holozoic nutrition occurs in consumers, while holophytic nutrition occurs in producers.  

Conclusion 

Holozoic nutrition is the type of nutrition that occurs in animals with a complete digestive system. In this mode of nutrition, animals internalize food particles, which contain complex organic substances in the form of solids and liquids. Therefore, it is a type of heterotrophic nutrition. Holophytic nutrition, on the other hand, is the type of nutrition that occurs in plants. Plants undergo photosynthesis, in which simple inorganic substances convert into simple organic substances by fixation of the energy from sunlight. Therefore, it is a type of autotrophic nutrition. Hence, the main difference between holozoic and holophytic nutrition is the method of obtaining energy and organic building blocks. 

References:

1. Atif, Bubly. “What Is Holozoic Nutrition.” LinkedIn SlideShare, 24 Sept. 2012, Available Here.
2. “Holophytic Nutrition.” Fine Dictionary, Available Here.
3. “Photoautotroph – Definition, Function and Types.” Biology Dictionary, 29 Apr. 2017, Available Here.

Image Courtesy:

1. “Amoeba (PSF)” By Pearson Scott Foresman – Archives of Pearson Scott Foresman, donated to the Wikimedia Foundation (Public Domain) via Commons Wikimedia   
2. “Troph flowchart” By Wickey-nl – Own work (CC BY-SA 3.0) via Commons Wikimedia   

About the Author: Lakna

Lakna, a graduate in Molecular Biology & Biochemistry, is a Molecular Biologist and has a broad and keen interest in the discovery of nature related things

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