Legion Posted April 8, 2008 Share Posted April 8, 2008 This is a criticism of NASA's newest Astrobiology Assessment by my associate Tim Gwinn. http://www.panmere.com/?p=74 Link to comment Share on other sites More sharing options...
Super Moderator florduh Posted April 8, 2008 Super Moderator Share Posted April 8, 2008 I didn't realize the definition of "life" was in question. Life is a cereal. No, it's a magazine. I don't see why it's remarkable that the definition of life was omitted from that paragraph. Other common terms weren't defined either. Yet, we all know what is meant. Can you touch on the significance? - Chris Link to comment Share on other sites More sharing options...
Guest end3 Posted April 8, 2008 Share Posted April 8, 2008 I don't know, it sounded as though they had not given much consideration to the complexity of the question.... Link to comment Share on other sites More sharing options...
Legion Posted April 8, 2008 Author Share Posted April 8, 2008 Yes Chris, currently the definition of life is of central concern to many biologists. As well it should be, because determining what constitutes life, in part, defines the scope of biology itself. Many have asked the question, “What is mind?†But this question may be far more fundamental. What is life? You say we all know what life is, but scientists are generally not allowed to have private, assumed, or implicit definitions. When called upon they must be able to say… “These are the natural systems that we study and this is how they are recognized or defined.†But biology cannot yet do this. This is significant in my opinion. End, they may very well have not considered the complexity of the question. I don’t know. But I suspect the time has come for biology to examine itself. The situation as it now stands is untenable in my estimation. Link to comment Share on other sites More sharing options...
Super Moderator florduh Posted April 8, 2008 Super Moderator Share Posted April 8, 2008 I didn't know it was so hard to define. I thought it was a life form if it converted energy and reproduced. There are other qualities such as response to stimulus, etc., and qualifications can be added or removed as the defining individual wishes. I'm just a simple guy. Link to comment Share on other sites More sharing options...
Guest Marty Posted April 8, 2008 Share Posted April 8, 2008 I just remember that song from my Sesame Street days... BTW, I couldn't get the video to just post within my post. I was trying to use the "Insert special item drop down, then selected "CODEBOX" Is this not the way to do it? It would just display the code, not the video when I went to preview the post. Link to comment Share on other sites More sharing options...
Deva Posted April 8, 2008 Share Posted April 8, 2008 This brings to mind the Star Trek episode where the silicone-based life forms that looked like rocks were discovered. I just wonder if extraterrestrial life will be at all easy to identify as such. Link to comment Share on other sites More sharing options...
woodsmoke Posted April 8, 2008 Share Posted April 8, 2008 I was thinking the same thing, Deva. The thing about "life" is we're only familiar with one incarnation of it. There's no reason I'm aware of why it should be restricted to a carbon base, that's just the way it happened to work with us. That said, it makes sense for NASA to have a carbon-based focus in their search for extra-terrestrial life, as that's the form with which we're most familiar, which should make it the easiest to spot and identify. Link to comment Share on other sites More sharing options...
The-Captain Posted April 9, 2008 Share Posted April 9, 2008 A bit closer to home biologists have debated whether viruses can be considered life. Viruses don't fit the common criterion for life,no cellular reproduction etc., yet they evolve and reproduce after a fashion. For them to be considered alive the scope of the definition of life would need to be expanded http://serc.carleton.edu/microbelife/yello.../viruslive.html I agree Legion, the definition of life is of paramount importance to the advance of biology. Link to comment Share on other sites More sharing options...
Legion Posted April 9, 2008 Author Share Posted April 9, 2008 I agree Legion, the definition of life is of paramount importance to the advance of biology. This is just another indication, to my mind, that you are wise beyond your years Doctor. In my estimation viruses are not alive. As I have come to understand it, an organism must have the capacity for metabolism and repair and these things must arise as a consequence of causes embedded entirely within the organism itself. Viruses must high-jack the metabolism of organisms in order to do anything at all. They have no metabolism of their own. However viruses are not outside the scope of biology because it would be very difficult to account for the behavior of the immune systems of organisms if viruses are not factored in. Link to comment Share on other sites More sharing options...
Ouroboros Posted April 9, 2008 Share Posted April 9, 2008 Astrobiology Magazine: Defining Life Link to comment Share on other sites More sharing options...
Legion Posted April 9, 2008 Author Share Posted April 9, 2008 Thanks for that Hans. In that article Carol Cleland says this... "What we need to answer the question, 'What is life?' is a general theory of living systems." I agree with her. And in my estimation this is what makes this question so potent. What is life? Link to comment Share on other sites More sharing options...
Grandpa Harley Posted April 9, 2008 Share Posted April 9, 2008 And then after virii, what about Prions? With the extended discovery of extremophiles, conditions for life have expanded, there seems to be no concomitant re-examination of what 'life' or 'to be alive' actually is... Link to comment Share on other sites More sharing options...
Legion Posted April 9, 2008 Author Share Posted April 9, 2008 And then after virii, what about Prions? With the extended discovery of extremophiles, conditions for life have expanded, there seems to be no concomitant re-examination of what 'life' or 'to be alive' actually is... Again, prions, like virii, have no metabolism of their own. I find myself in resonance with Robert Rosen. Organisms, at a minimum, must have the capability of metabolism and repair. And I disagree with those who say that these aspects, metabolism and repair, are going to be unique to terrestrial organisms. As for extremophiles… My guess is that the first terrestrial organisms were extremophiles. Link to comment Share on other sites More sharing options...
Grandpa Harley Posted April 9, 2008 Share Posted April 9, 2008 Virii do have a metabolism, since they steal it... specifying how one gets a metabolism is beyond the scope. The need one to breed... It's like saying a seed isn't alive... Prions I wouldn't class as life, but they exhibit Link to comment Share on other sites More sharing options...
Grandpa Harley Posted April 9, 2008 Share Posted April 9, 2008 Virii do have a metabolism, since they steal it... specifying how one gets a metabolism is beyond the scope. The need one to breed... It's like saying a seed isn't alive... Prions I wouldn't class as life, but they exhibit some of the characteristics and we could both be proved wrong in our assessment in the future... Link to comment Share on other sites More sharing options...
Legion Posted April 9, 2008 Author Share Posted April 9, 2008 Virii do have a metabolism, since they steal it... specifying how one gets a metabolism is beyond the scope. The need one to breed... It's like saying a seed isn't alive... I should have been more specific. I think that the metabolism must arise from within the system itself in order to be classified as an organism. As you pointed out virii must steal a metabolism to do anything. I don't understand the analogy with seeds Gramps. It seems to me that seeds have a metabolism that arises entirely from within the seed. Link to comment Share on other sites More sharing options...
Grandpa Harley Posted April 9, 2008 Share Posted April 9, 2008 Not without soem pretty narrow conditions. Virii do their thing by bring triggered by contact with a cell membrane... they have a form of energy storage to perform the actions for them to bootstrap into the cell... plant seeds need warmth and moisture to trigger the first part of their metabolic action which is break their own shell etc... Link to comment Share on other sites More sharing options...
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