Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • NCERT
  • What is meant by living? Give any four defining features of life forms.

What is meant by living? Give any four defining features of life forms.

Answers (1)

Ans: An organism is considered to be living if it is capable of evolving, self-replicating, responding to external stimuli, etc. Nutrition, response to stimuli, reproduction, and growth are several aspects of living beings, but they are not the defining features of life forms. Growth is often mistaken to be a defining feature of life forms, but it is not the case as a few non-living things like snowballs, clouds, etc. can also gain mass, volume, and space. So, growth is not a defining feature for living beings.

The four defining features of life forms are: -

  • Metabolism: The collection of several biological reactions in the living being comprises the metabolism. Metabolism includes the breakdown and formation of various molecules to carry out the biological reactions in living organisms. Since metabolism requires a system comprised of cells to be carried out, it is quite evident that this cannot be done in non-living things. Though a few in-vitro reactions have been tried in the laboratories to imitate metabolism, that is not real metabolism. Thus, metabolism is one of the defining features of life.

  • Reproduction: Reproductions are carried out by living organisms to produce offspring like them. Reproduction could be either sexual reproduction or asexual reproduction, but the act of producing offspring of your kind is a feature of living organisms alone. Though there are a few living organisms like the worker bee, that do not reproduce, that does not take reproduction down as a defining feature of the life forms because reproduction cannot be carried out in non-living things. Thus, reproduction is a defining feature of life forms.

  • Response to stimuli: The stimuli can be felt by the organisms either externally in the form of temperature, touch, light, etc. or internally via hormones like dopamine, estrogen, etc. The response to the stimuli is a defining feature for living beings because they can sense a change in their environment whether externally or internally and respond to it most suitably according to their convenience. This sense of consciousness is absent in non-living beings, and thus, it is a defining feature of the living forms.

  • Structural organization: The structural organization, whether on a cellular level or at an upper level, is found in living beings. Various molecules come together and arrange themselves in a particular arrangement to form cell organelles, and these cell organelles further arrange themselves in a specific fashion to form cells. These cells come together to form various tissues, and then these tissues further arrange in a way to form various organs present in living beings. These organs are what the body of the living being functions. This arrangement from the cellular level up to the organ level is an extremely advanced and complicated manner of structural organization which cannot be made in ton-living beings. The arrangement of each cell organelle matters as the different arrangements form different cells; each cell arrangement further makes different tissues, and each arrangement of tissues makes different organs. This level of hierarchy is not possible in non-living things, and thus the structural organization is a defining feature of living beings.

 

Posted by

infoexpert22

View full answer

Similar Questions

Latest Question