Biology

Life Processes, Nutrition and Food

What is Biology: (Gr. Bios- Life, Logus –Study)

Study of life called Biology

What is life?

Life is AIR
A         Adaptation
I          Irritability
R         Reproduction

Thus, life is accumulation of adaptation and reproduction

Adaptation: To cope with the changed environment
Irritability: Response to stimuli
Reproduction: Perpetuation of species
Stimuli: Any external factor that changed the normal environment of life is called stimuli


What is Life Processes?
A complex processes of organ systems like digestive systems, respiratory system, circulatory system, excretory system, reproductive system etc. is called life processes.


What is Nutrition?
The mode of obtaining food is called nutrition.
What are the types of Nutrition?

  • Autotrophic Nutrition

  • Heterotrophic Nutrition

What is Autotrophic Nutrition?
The process by which living organisms synthesize food by own

  • Photoautotrophic: Food is synthesized by using light

  • Eg. Green Plants

  • Chemoautotrophic: Food is synthesized by using chemicals

  • E.g Sulphur bacteria, iron bacteria, Nitrogen bacteria etc.

What is food ?

Anything that we eat which provide energy and is responsible for normal growth and proper function of the body is called food. 

What are the components of Food? 
There are seven components of food. They are as follows:

  • Carbohydrate

  • Proteins

  • Fat

  • Minerals

  • Vitamins

  • Water

  • Roughage


What is Heterotrophic Nutrition? 
The mode of nutrition in which living organisms depend upon others for food is called heterotrophic nutrition.
What are the Types of Heterotrophic Nutrition?

  • Parasitic Nutrition: The nutrition in which living organism obtain food from the host body

The organisms on which organisms depend are called hosts while depend organisms are called parasites:


Types of Parasites?

  • Ectoparasite: Parasites which live outside the host body

Eg. Ties, Mites etc.

  • Endoparasties: Parasites which life inside the host body Eg. Flat Worm

Symbiotic Nutrition: Two living organisms which are inter-dependent and both are benefitted
Eg. E Coli, Lichen
Saprophytic Nutrition: The mode of nutrition in which an organism derives its food from dead and decaying organic matter.
Eg. Mushroom


Holozoic Nutrition: The mode of nutrition in which organisms feed exclusively on the solid organic food materials. It is called animal life nutrition. It completes in five steps:-

  • Ingestion:- Taking of food
  • Digestion: - Break-down of food
  • Absorption: - Transfer of food for from digestive system to blood.
  • Assimilation:- Distribution of food in different parts of body
  • Egestion:- Removal of undigested food from the bod

On the basis of source of food it is of three Types:

  • Herbivores:- Organisms that depends upon plants directly

Eg. Rabbit, Cow etc.

  • Carnivores: - Organisms derive their organic food from animal food.

Eg. Lion, Tiger etc.

  • Omnivores:- Organisms which feed upon both plants and animals

Eg. Human beings, Crow, Ant etc.