Excretion Definition

Excretion, in biology, is the process by which organisms expels metabolic waste products and other toxic substances from their body

Excretion is observed in every living organism, hence, it is an important life process. Excretory products are created as a by-product of metabolic and non-metabolic activities. The waste products animals generate are classified as either metabolic wastes or non-metabolic wastes. Metabolic wastes are generated as a by-product of metabolic activities. Examples of metabolic wastes include gases, liquids and solids. Non-metabolic wastes are generated when a substance is no longer usable or digestible by an organism.

Even plants excrete wastes – for instance, the process of photosynthesis results in the creation of oxygen and water. Both these substances are considered as waste products and require removal. Even unicellular organisms produce waste products – Thiobacillus denitrificans, a denitrifying sulphur bacteria, produces nitrogen gas as the excretory product. Rubber trees exude latex and resins as waste products.

Main Article: Excretory Products and their Elimination

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Frequently Asked Questions on Excretion


Define Excretion.

Excretion is the process by which organisms expel metabolic waste products and other toxic substances from their body.


What are the excretory products of humans?

The major excretory products of humans are urea. Apart from this, carbon dioxide and excess water are also excreted.


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