Excretion in Animals


 
 
Concept Explanation
 

Excretion in Animals

Excretion in animals: Many unicellular organisms like Amoeba throw out their wastes by diffusion from their body surface. Protozoans have no organs for excretion. As they live in an aquatic habitat, their wastes are eliminated by diffusion through the plasma membrane.

Simple multicellular organisms like Hydra throw out solid waste matter through their mouth. Higher multicellular organisms have well-defined specialized excretory organs. These organs could be simple tubular structures called as nephridium in flatworms and leech.

The excretory organs of insects (e.g., grasshopper, cockroach and housefly) are also tubular.They are known as Malpighian tubules.  They remove nitrogenous wastes from the body fluid and help in maintaining the water balance in the body.

In vertebrates, the main organs of excretion and maintenance of water balance are the kidneys.

 

 

Sample Questions
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Question : 1

Which of the following are correct ?

(a) The excretory organs of insects (e.g., grasshopper, cockroach and housefly) are tubular and are known as malpighian tubules .

(b) Malpighian tubules remove nitrogenous wastes from the body fluid and help in maintaining the water balance in the body.

(c) In vertebrates the main organs of excretion and maintenance of water balance are the kidneys .

Right Option : D
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Question : 2

In higher multicellular organisms the excretory organs could be simple tubular structures called  _______________ in flatworms and leech.

 

Right Option : B
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Question : 3

Which of the following statements about excretion is true?

Right Option : D
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