THE LIVING WORLD
📌 Introduction :
When I observe nature around me, I see plants, animals, birds, insects, and many
tiny organisms that cannot be seen with naked eyes. All these together form the
living world.
Biology helps us understand what life is, how living organisms behave, and how
they are classified in a scientific way.
🌱 What Does “Living” Mean ?
Living organisms show certain basic characteristics that make them different
from non-living things.
** Characteristics of Living Organisms
1. Growth :
All living organisms grow internally due to cell division.
Growth in living beings occurs from within.
Example: Human baby → adult.
*((Non-living things like crystals also grow, but they grow by external deposition,
so it is not true growth.))
2. Reproduction :
, Living organisms have the ability to produce young ones.
It may be:
o Sexual reproduction
o Asexual reproduction
((Some organisms like mule do not reproduce, yet they are living.
➡️So reproduction is not an absolute defining feature.))
3. Metabolism : (Very Important)
All chemical reactions occurring inside a living body are called metabolism.
It includes:
o Anabolism – building reactions
o Catabolism – breaking reactions
👉 Metabolism occurs only in living organisms.
4. Consciousness : (Response to Stimuli)
Ability to sense and respond to surroundings.
Stimuli can be:
o Light
o Heat
o Sound
o Touch
o Chemicals
:
*(( Consciousness is the most defining property of living organisms)).
🧬 Diversity in the Living World :
The number of living organisms on Earth is extremely large.
To study them easily, scientists arranged them in an organized system called
classification.
📌 Introduction :
When I observe nature around me, I see plants, animals, birds, insects, and many
tiny organisms that cannot be seen with naked eyes. All these together form the
living world.
Biology helps us understand what life is, how living organisms behave, and how
they are classified in a scientific way.
🌱 What Does “Living” Mean ?
Living organisms show certain basic characteristics that make them different
from non-living things.
** Characteristics of Living Organisms
1. Growth :
All living organisms grow internally due to cell division.
Growth in living beings occurs from within.
Example: Human baby → adult.
*((Non-living things like crystals also grow, but they grow by external deposition,
so it is not true growth.))
2. Reproduction :
, Living organisms have the ability to produce young ones.
It may be:
o Sexual reproduction
o Asexual reproduction
((Some organisms like mule do not reproduce, yet they are living.
➡️So reproduction is not an absolute defining feature.))
3. Metabolism : (Very Important)
All chemical reactions occurring inside a living body are called metabolism.
It includes:
o Anabolism – building reactions
o Catabolism – breaking reactions
👉 Metabolism occurs only in living organisms.
4. Consciousness : (Response to Stimuli)
Ability to sense and respond to surroundings.
Stimuli can be:
o Light
o Heat
o Sound
o Touch
o Chemicals
:
*(( Consciousness is the most defining property of living organisms)).
🧬 Diversity in the Living World :
The number of living organisms on Earth is extremely large.
To study them easily, scientists arranged them in an organized system called
classification.
