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Concept of Living and Need for Classification - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:34 AM | #NEET

Quick Facts

  • What is Living is considered one of the most asked concept.

  • 22 Questions around this concept.

Solve by difficulty

It is much easier for a small animal to run uphill than for a large animal, because 

Which one of the following aspects is an exclusive characteristic of living things?

Concepts Covered - 2

What is Living

 

What is living
 
The beings or objects showing growth, development, responsiveness, adaptation, and reproduction are called living beings.
 
Important characteristics of living beings
 
Cellular structure
 

  • All living beings are made up of a number of cells. These cells contain protoplasm or living matter. 
  • The cellular structure is the defining property of living beings as all the processes are related to the structure of cells. 
  • Protoplasm and cellular structure are absent in viruses.  

Metabolism  
 

  • It refers to all the chemical reactions, occurring within the body of living organisms.  These reactions can be grouped into two types i.e. anabolism and catabolism.
  • Anabolism: Processes or reactions including the formation of complex substances from simpler ones. E.g. photosynthesis
  • Catabolism: Processes or reactions including the breakdown of complex substances into simpler ones. E.g. respiration

Growth 

  • It refers to an irreversible increase in the mass of an individual.
  • In plants, growth continues throughout life due to the presence of meristematic tissue. In animals, growth is definite.
  • Growth in unicellular organisms is through cell division.

Reproduction

Organisms can produce new individuals that are similar to them through a process called reproduction. It is required for the perpetuation of living organisms. 


Consciousness/ Response to stimuli

  • It refers to the awareness of surroundings by showing a response to an external stimulus. All organisms can sense and respond to the environment. 
  • The ability of organisms to react to an external stimulus is called irritability.  
  • Higher animals possess sense organs for sensing the stimuli. Plants do not have sense organs but they respond to stimuli by showing some movement. 

Movement

  • All organisms show some kind of movement. 
  • Animals show locomotion.
  • Plants, though do not show locomotion, but exhibit movements. 

Homeostasis

  • It refers to maintaining a favorable internal environment despite fluctuations in the external environment. 
  • Livings beings have a self-regulated system to adjust and maintain the internal environment. 


Adaptations 

Adaptations refer to changes acquired by an organism over a period of time in order to survive in a particular environment. 

Death 

  • It refers to the stoppage of all vital activities due to ageing, disease, accident, etc. Complete death is absent in unicellular organisms. 
  • They multiply by fission and the parent cell continues living as a daughter cell however, it loses its own identity. 
  • Unicellular organisms are thus immortal.
     
Biodiversity and Need for classification
  • There is a wide variety of living organisms differing in their size, colour, behaviour, habits etc. This diversity is referred to as biodiversity. 
  • The term biodiversity was coined by Edward Wilson. 
  • Currently, there are some 1.7-1.8 million species known to mankind. 
  • It is believed that this is 2 % of all the species occurring on earth. 

Need for classification 

  • Due to such a large diversity of life forms, a proper system of classification is required because it is not possible to study every organism. 
  • We can study, some members of a group to ultimately know about the whole group. 
  • Without any classification system, organisms cannot be identified.
  • classification also helps in knowing the relationships amongst different groups of organisms. 
     

Study it with Videos

What is Living
Biodiversity and Need for classification

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