Life means different things to different people. But nobody truly knows life until they know what it really is and which structure on earth is more suitable to carry it on. This article defines Life in practical terms and identifies the biological cell as the host of the living principle.
First of all, what is LIFE? What is the definition of Life?
According to dictionary.reference.com, Life is: 'the condition that distinguishes organisms from inorganic objects and dead organisms, being manifested by growth through metabolism, reproduction, and the power of adaptation to environment through changes originating internally", among other definitions.
Another definition online is from merriam-webster.com/ and it says that life is " the quality that distinguishes a vital and functional plant or animal from a dead body b : a state of living characterized by capacity for metabolism, growth, reaction to stimuli, and reproduction", still among other definitions.
Does these definitions tell you the reader what life really is? Maybe so, maybe not.
To define life the way most people can understand what it really is we have to look at living organisms and see what they do differently from non living things.
Life deals with movement, activity, creativity, adaptation to environmental changes, growth, reproduction, limited size, specific form, etc. but those factors are not specific to living organisms. If you look carefully you will find most of them if not all, related to non living things as well. What living things do differently from non living things is:
try to experiment most of them instead of just one or a few contrary to what we see in non living things that individually pick up some factors and leave out others
combine all these factors in a process or a plan towards the achievement of personal gaols and hopefully a final goal
Living organisms are part of the Nature. They do not do things that no non living thing can not do. THey most of the time do things that are done in Nature. But they are able to do many things over and over following a plan.
Living organisms work but they are not the only workers on Earth. Work being the ability to move and/or transform things, we know that Water and the Wind for example work well just like the Sun light does. What living organisms do differently is use work to meet personal goals and be able to hopefully transmit this work to new living organisms self-made or available. So what is Life? How can we now define Life?
Life is simply a useful work!
Life is a work done by an element of Earth in order to attain personal goals that are mainly self-protection, growth, communication, interactions, creativity, adaptation to environment and reproduction/birth.
In practical terms Life is a process of useful assimilation of energy/matter by a so-called living organism. In order to continue living such an organism absorbs external energy/matter, digests it, retains useful elements that most of the time are used to make new specific energy/matter that is integrated into its body and throws the waste products away. The fact of taking external energy/matter and be able to put most part of it in its body so that external energy/matter is now intrinsic part of the body is what is termed the assimilation ability of the living organism. But since that assimilation has a purpose, I call it useful assimilation. So what is Life then now?
Life is a useful assimilation of energy/matter.
How useful is this assimilation? It allows the living organism to self sustain itself, adapt to the environment, be more creative, grow if needed and reproduce if possible.
What are living organisms, those earth elements able to do a work termed useful assimilation?
If you look carefully and analyze them with scientific tools you will find that all so-called living organisms are biological cells or society of cells, that is those we call microorganisms (single cells and small societies of cells) and animals and plants commonly called pluricellular organisms. We can now simply call livings things cell organisms.