Sciencemadness Discussion Board

Primitive life

plante1999 - 11-11-2011 at 20:25

Fallowing wath I read a live should make more of wath it is made (duplicate its component). It also should use catalist.

Fallowing this ''THE simplest'' form of live will be Formamide if CO and NH3 is disolved in the formamide it will catalise the reaction of these 2 compound to make more formamide...

But I suppose there is sol. of inorganic chemical that could be called primitive lives if they are mixed with Building block of these primitives lives.

Lets debate about this!


Thanks!!!


Endimion17 - 12-11-2011 at 05:48

No, that would not be "primitive life". Life is a phenomenon that's much more than just duplicating itself. Otherwise, a crystal emerging from a saturated solution would also be a living thing, and it isn't.

It's true that there isn't a strict boundary between living and nonliving matter, but a simple progressive reaction that catalyzes itself simply isn't living.

plante1999 - 12-11-2011 at 06:28

So if it use a catalist cycle to regulate ''himself'' does it make this ''thing'' a primitive live?

I like to debate about this type of subject!

Endimion17 - 12-11-2011 at 07:44

No, it doesn't. There's no metabolism of any kind. Yes, the local entropy diminishes at the expense of heat release, but that's not life.

Let me demonstrate one more analogy (the first one being the crystal).
Rain. Rain is formed when there's enough relative humidity in one area of atmosphere, and centers for crystalization such as very small dust particles. If there aren't any centers, there'll be no rain.
So you've got one speck of dust that gathers few ions and water molecules. A cascade precipitation occurs. The larger the drop, the more water it "sucks" until it becomes so heavy it can not float and falls down. Soon the cloud reaches a stable relative humidity level and the precipitation stops. Just as the crystal will stop growing when the concentration of its ions drops, or the formamide synthesis when the level of ammonia or carbon monoxide drops.

That is a reaction (physical type) that catalyzes itself. It does not moderate itself. It just proceeds until there are no "reactants" left.

The formamide replicating reaction, as well as other similar reactions, might have a role in early Earth filled with noxious fumes, bombarded by solar radiation and heated by meteoroid impacts and volcanic activity, but can't be considered life.
Life started to emerge when vastly more complex molecules appeared. It did not appear spontaneously. There was a "gray zone" of abiogenesis which is currently being researched a lot.

White Yeti - 12-11-2011 at 12:26

I agree, otherwise, by your definition, viruses would be living things.
Living things are things that can carry out all the life functions, I know this is very middle schooly, but it's true. Viruses are special in that they carry out all the life functions only when introduced into a host. Furthermore, they contain DNA, the centrepiece of all life on Earth.

Sedit - 13-11-2011 at 07:16

Are viruses nothing more then primitive parasites? There are a host of parasites on this planet unable to perform the functions of life without the use of a host.



Consider the first reaction. Give it a large amount of space to carry out the reaction. Now what if there was a factor added so that the formamide was destroyed yielding CO and NH3 so that the cycle could start over again.

I have the personal belief that all that is needed for life is a liquid planet of any kind, A variable energy source, and terrain so that pools of isolated reactions can happen independent of the main body of fluid. In short order life will start to self organize.

White Yeti - 13-11-2011 at 07:34

Quote: Originally posted by Sedit  
Are viruses nothing more then primitive parasites? There are a host of parasites on this planet unable to perform the functions of life without the use of a host.


Even complex parasites can perform all the life functions outside of a host. Take a leech for example, when it absorbs enough blood from a host, it detaches and enters a period of semi-dormancy, where it metabolises all the nutrients it acquired. Even during this period of dormancy, it performs six of the seven life functions. It is not reproducing per se, but it has the capability of reproducing **independently** from its host.

A virus cannot be identified as a living thing because it is not even a cell. It is merely a piece of protein and DNA (RNA in special cases). In fact, the only two life functions a virus can perform in a host are reproduction and evolution. You will agree that viruses do not have a metabolism of any kind, they do not respond to stimuli, they do not grow and they cannot maintain homeostasis. This quite clearly shows that they are not living things, and that, comparatively, they are about as living as the enzymes in your digestive system.

Endimion17 - 13-11-2011 at 07:43

Viruses are the gray zone because, if we observe them as a blackbox model, they resemble something many other macroscopic critters do, but don't have a metabolism. But they're just complex genetic information in a molecular form.

Some of you might not know, but viruses are the same thing as some self replicating pieces of junk DNA in our genome, except they're sometimes outside the cell on their own. But essentially, they're nothing more, in the information sense.

There are even some viruses that reside in the dormant form, as pieces of genetic information in our very own DNA molecule, but don't get the chance to replicate because their code lacks some parts (it degenerated and they're actually stuck!) that transcribes to essential things like protein capsule etc.
I find that to be extremely fascinating to the point of jumping around and telling people about it. :D

And there are viroids, prions... All that is the gray zone. Life isn't something digital. It's very analogue and subjected to a relative point of view near the ends of its spectrum.

[Edited on 13-11-2011 by Endimion17]

Sedit - 13-11-2011 at 14:35

Endimion17, do you have a source for the virus DNA being incorporated into the human genome? I remember reading about this sometime back and i'm curious about why. It would seem reasonable that Viral DNA is in our genome due to T-cells. They function by detecting viral proteins. I wounder if those humans who shared DNA with the viruses stood the test of time where as those who did not have the immunity already in place did not survive to pass there DNA to the next generation.

Quote:
Even complex parasites can perform all the life functions outside of a host.

Keyword, complex.

As we start to fully understand of the possibility of extra-terrestrial life this grey area of prions and viruses might become less grey over time. We are viewing life the only way we know how at the moment. Over time we may see a great change in what we understand life to be.