That’s Life…what’s life?

Well, I’ve decided that I may not be particularly fond of blogging…for two reasons. First, I tend to have a lot more to say as I run out of space (so sequels may be in order), and second, I tend to have more topics invade my brain as I’m trying to finish the thoughts of the current blog. This is a prior invasion…

The joke goes: Well, that’s Life… what’s Life?… its a cereal…really, how much does it cost?… $2.50…I only have $2.00…well, that’s Life. ba dum tsh.

This blog is about life.  You see, I am a biologist by training. By definition I am one who studies life. But it is hard to actually define life.

Merriam-Webster defines Life as  :the ability to grow, change, etc., that separates plants and animals from things like water or rocks

Now I know that is a definition, but it is really about characteristics of life. We have an easy time telling life from non-life. Does it grow, change, move or just sit there like a rock?

Even children and animals can recognize life, they see a stick on the ground then, whoop! it moves so it could be a snake…

We see the characteristics and know, this is life, but what makes something change from non-life to life? What is the essence of life?

You can’t just add electricity (sorry Dr. Frankenstein…), but there is a type of electricity involved with life processes. Some form of DNA/RNA is present in life as we know it. You have to have oxygen, but not all life needs it. And with the organisms that need it, too much harms life. Water is also a necessity, but again too much is a bad thing. It’s not a simple recipe.

Scientists have 3 rules of life, called the cell theory.

  1. The cell is the most basic unit of life.
  2. All living organisms are composed of one or more cells.
  3. All cells arise from pre-existing, living cells.

But these are not the essence of life. Scientists don’t know how to take a set of non-living chemicals and put them into a cell (the basic unit of life) and make it come alive. Even the right chemical balance taken out of the cell membrane becomes “dead”.

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Photo Credit: Curious Expeditions via Compfight cc

And there is a complex hierarchy of life or different levels of life. By that I mean that we are alive as organisms (Level 1). If our brains cease to function then we die. However, our organs can remain alive if donated to another body (Level 2). We are not alive, but part of us is.

And if you break the organ down into its cells, then the organ is dead, but the cells can be kept alive (Level 3).

Then if the cells are tweaked properly, they can be grown into another organ. Or the cells can be put into a prepared egg and become another organism (theoretically at least, see last week’s blog).

My kidney is not me, but it is a part of me. If I lose a kidney, I don’t cease to exist, but how many parts can I lose before I am no longer me? And some parts seem to define me or my image of me more that other parts.

And when did I begin? Does life begin at birth? Well, a level of life might begin there or another level after we reach a certain age of independence. That was 18 back in the day, but now seems to be more like 34…

Of course another level is when the egg and the sperm unite…conception begins that process of life.

But in reality we don’t create life at conception. Cells come from pre-existing cells, or life comes from pre-existing life.

Once life began at…well, the beginning, it has not stopped. It takes a living cell to make another living cell. Mama’s egg was alive before conception (as was Daddy’s sperm).

We are part of a great continuum of life. Part of a journey. Then when do I cease to be me? …cease to exist? (Ah…add a dash of sequel dust here…)

dsb

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David Brooks

Associate Professor of Biology & Nursing at East Texas Baptist University

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