How consciousness become the defining property of living organisms?

Explanation

All living organisms have excellent ability to sense their environment.
They respond to various physical, chemical and biological stimuli.
The various external factors to which living organisms respond are light, water, temperature, pollutants, other organisms etc.
We sense our environment through our sense organs.
All organisms from the prokaryotes to eukaryotes can sense all respond to environmental cues.
Plants responds to external factors like light, water, temperature, other organisms, pollutants etc.
 Photoperiod affects reproduction in seasonal breeder both plants and animals.
All living things responds to all living things as they have additional ability of self consciousness.
Consciousness therefore, becomes the defining property of living organisms.