Question

Difference in excretion by plants and animals.

Answer 1

Chemical reactions occur in the cells of living organisms all the time to carry out the life processes.

The sum of these reactions is called metabolism. Metabolism produces useful products as well as toxic (poisonous) by-products.

These toxic substances have to be removed as they are harmful if allowed to accumulate. The removal of metabolic waste products from the body of an organism is known as excretion.

The major excretory products are carbon dioxide, excess water, and nitrogenous compounds like ammonia, urea, uric acid, etc. Carbon dioxide and water are produced in the process of tissue respiration. Nitrogenous compounds are formed from the breakdown of proteins and amino acids. Water and salts in excess of the body’s needs are also excreted.

We acquire most of the water with our food and drink and some by metabolism, e.g., the water produced during cellular respiration. Other excretory products include chemicals from medicines, toxic substances, and circulating hormones that have already served their purpose. We will learn how metabolic wastes get eliminated.

Excretion in animals:

Many unicellular organisms like Amoeba throw out their wastes by diffusion from their body surface. Protozoan’s 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 as in flatworms and leech.

The excretory organs of insects (e.g., grasshopper, cockroach and housefly) are also tubular. 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.

Answer 2

Excretion in plants is done by transpiration .

In this water loss outside the plant is done.

Excretion in animals take place by many methods some of them are as follows :

• Sweat is released from our body by many different processes.

This sweat contains many chemicals like urea , etc.

• The liquid waste that is separated by kidneys from blood is known as urea.

This urea is released from the body in the form of urea.