Posted on 07/04/2004 5:19:27 PM PDT by PatrickHenry
I would like to think the definition of life involves a Russian doll of attributes. I don't have the technical background to list everything, but it would seem that replication is the most essential attribute, followed by variation, followed by metabolism.
Drawing a fixed line in the sand and saying this list of attributes is required to call something living seems to me more of a political or religious statement than a scientific one.
I would also argue that on earth at least, life is a community that supports a lot of parisitic entities. I am not convinced that viruses should be excluded from the definition of life simply because they require a host, any more than a fetus or profoundly retarded person should be classified a non-human because it can't request an attorney.
In South East Illinois last week the corn was 7 feet high before the fourth of July. Bumper crops.
On the other hand, this is the first year I've tried growing potatoes, and I have Yukon Gold bakers as big as your head.
How long does it take to bake one of those volley balls?
It's more complicated than it seems at first. Is a sperm cell living? An unfertilized egg? A fern spore? (I would have added lichens, but I think in all cases studied, the fungi and algae involved can live separately.)
Mostly the boundary isn't important outside politics or religion as you point out. A koala cannot live outside it's few trees-of-interest nor can a panda live outside restricted areas. Tubeworms have to live near black smokers.
Shannon Entropy: Poor Terminology! The story goes that Shannon didn't know what to call his measure and so asked the famous mathematician von Neumman. Von Neumann said he should call it the entropy because nobody knows what that is and so Shannon would have the advantage in every debate! This has led to much confusion in the literature because entropy has different units than uncertainty. It is the latter which is usually meant. If one does not use correct units, one will not get correct results. Recommendation: if you are making computations from symbols, always use the term uncertainty, with recommended units of bits per symbol. If you mean the entropy of a physical system, then use the term entropy, which has units of joules per kelvin (energy per temperature).
--- Claude Shannon, A Mathematical Theory of Communication, Part III, section 20, number 3
I think y'all are over-complicating this question of what differentiates between that which is alive and that which is not.
Take two cells, the same type of cells. Kill one. Compare them. What is the difference?
One is dead. The other is alive. But that isn't the interesting case (although it may be rather difficult to tell whether a cell is dead or alive.)
Living creatures can have dead cells (hair, nails, skin) and dead creatures can have living cells (all cells do not die at the same time when a mammal dies; some may even be kept "alive" indefinitely in a nutrient broth.)
The requirement of restricted environment shouldn't disqualify something from being called living.
Actually it is the reduction of that uncertainty.
You could call a boiling pot of water living if you want to. That does not make it so. A virus needs a host not just to survive, it needs a host before it can do anything. Any parasite that is alive, replicates by itself and metabolizes by itself. It may require food and some components from its host to complete its life cycle, but it nevertheless can do something without a host. And your strawman human, is non-existent. A human is not defined by the ability to request a lawyer nor to build strawmen.
Glimpse at Early Universe Reveals Surprisingly Mature Galaxies
Observations challenge standing view of how and when galaxies formed
A rare glimpse back in time into the universe's early evolution has revealed something startling: mature, fully formed galaxies where scientists expected to discover little more than infants.
"Up until now, we assumed that galaxies were just beginning to form between 8 and 11 billion years ago, but what we found suggests that that is not the case," said Karl Glazebrook, associate professor of physics and astronomy in the Krieger School of Arts and Sciences at The Johns Hopkins University in Baltimore and co-principal author of a paper in the July 8 issue of Nature. "It seems that an unexpectedly large fraction of stars in big galaxies were already in place early in the universe's formation, and that challenges what we've believed. We thought massive galaxies came much later."
Living creatures can have dead cells (hair, nails, skin) and dead creatures can have living cells (all cells do not die at the same time when a mammal dies; some may even be kept "alive" indefinitely in a nutrient broth.)
Just take two skin cells, one alive, one dead and describe the difference between them.
In my view, that is the first question which must be answered before anyone can seriously approach the "origin of life" question.
This evilutionist doesn't. I think the hallmark of life is a complex metabolism feeding on a relatively simple environment.
"This was the most comprehensive survey ever done covering the bulk of the galaxies that represent conditions in the early universe," Glazebrook said. "We expected to find basically zero massive galaxies beyond about 9 billion years ago, because theoretical models predict that massive galaxies form last. Instead, we found highly developed galaxies that just shouldn't have been there, but are."
These findings challenge the dominant theory of galactic evolution, which posits that at this early stage, galaxies should have formed from the bottom up, with small pieces crashing together to build small and then ever larger galaxies. Called the "hierarchical model," this scenario predicts that normal-to-large galaxies such as those studied by GDDS would not yet exist.
I have asked that question on these threads a number of times. What would you say about a snipet of DNA that is excised from one cell and inserted into a viable, reproducing line of creatures, possibly of another order?
The "live" cell will be generally more active than the "dead" cell. (Chemical reactions going on, etc.) The problem is that is nearly impossible to tell a live from a dead cell. I'm not sure there can be (even in theory) a test for live vs dead at the individual cellular level. If I could tell for sure, I'd apply the test to grass seeds for commercial use.
WOW! A little revision needed.
There is so little that we know for sure.
So things that require a more complex environment than, say, water, sunlight, CO2 and nitrogen, are not alive?
Plant 'em.
What the heck, toss in carbon and a few other elements.
"Some new ingredient is required to make more stars form earlier in the big galaxies. But what that ingredient is, we don't yet know."
Really?
P.S. This one needs it's own thread. Sorry for the intermission.
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