Life Processes And Modes Of Nutrition

Q 1. What are life processes?Answer: The basic functions performed by living organisms to maintain their life on this earth are called life process.

• Steps of life process:

Movement,Reproduction,Sensitivity,Nutrition,Excretion,Respiration and Growth

1. Movement: All living organisms exhibit movement, most of the animals, Monera and Protista move from one place to another it is called locomotion stationary plants and fixed animals exhibit moment of their parts for example, bending of roots, beating of heart, breathing etc.

2. Reproduction: it is one of the important processes by which every living organism make a copy like itself it is the means of multiplication processes by which every living organism makes an individual of each species till death.

3.Sensitivity: this means that living thing respond to condition is around them eg, green plants grow towards sunshine certain microbes shrink into balls when something touches them human beings show this kind of sensitivity by blinking when sun rays fall into their eyes.

4. Nutrition: All living organisms need matter to build up the body and energy to operate the metabolic reaction that sustain life. The materials which provide the two primary requirements for life namely matter and energy are called nutrients of food. The sum total of the processes by which the living organism obtain matter and energy is termed as nutrition.

5. Excretion: The elimination of metabolic waste products from the animal body to regulate the composition of the body fluids and tissues is called excretion.

6.Respiration: It can be defined as the exchange of environmental oxygen with the carbon dioxide produced in the cells during oxidation.

7.Growth: It is defined as a permanent and irreversible change in the size of a cell ,organ or whole organism usually accompanied by an increase in dry weight.

Q 2.Autotrophic nutrition: the mode of nutrition in which an organism makes or synthesis its own food from the simple inorganic materials like carbon dioxide, water, and sunlight present in the surroundings.
Autotrophic nutrition is found in all green plants the process of making food is known as photosynthesis.

• Heterotrophic nutrition: The mode of nutrition in which an organisms cannot make or synthesis its own food with the help of carbon dioxide ,water and sunlight and depends on other organisms for it is food.
It is found in animals like Fungi, some Protista and Bacteria. Those organism which depend on other organism for their food is called heterotrophic nutrition.• Types of heterotrophic Nutrition:
(a)Saprotrophic nutrition: it is that mode of nutrition in which organisms absorb fluid food through the body surface. In this nutrition organisms obtain its food from decaying organic matter of dead plants, animals etc. The organisms having saprotrophic mode of nutrition are Known as saprotrophic nutrition.

(b)Holozoic nutrition: it is that nutrition in which an organism takes the complex organic food materials into its body by the process of Ingestion. The ingested food is digested and then absorbed into the body cells of the organism since it is characteristics of animal so it is also known as holozoic nutrition.

(c)Parasitic nutrition: it is that mode of nutrition in which an organism obtain its food from the body of another organisms (host) without killing it. The organisms which obtain the food are called a parasites. So, this process is known as parasitic nutrition.

(d)Mixotrophic nutrition: it is mode of nutrition in which organisms(Euglena) carries both autotrophic and heterotrophic mode of nutrition at the same time this is called mixotrophic nutrition.