Debate and discussion of any biological questions not pertaining to a particular topic.
What exactly is the difference between a living thing and a non-living thing?
By golly, I don't want the primary school answer to the question. I want a clear fundamental distinction between the things that live and the ones that don't.
Honestly, who would like it? This kind of answer is nothing but a temporary plasma that fills the ever-expanding gap called curiosity.
Well...seems like everyone has their own line of distinction for life. But, how about something more fundamental? I'd be impressed if the lack of one specific, fundamental, everlasting, independant (i.e. not influenced by its surroundings. unlike evolution.) characteristic in a living species can get it classified under the "lifeless" category.
It may very well be that we will someday discover a form of "life" that is utterly unlike what we consider to be life. But until then, we've got a pretty good idea of the parameters within which "life" can occur on earth. The only vagueness occurs with, like mith said, things like viruses.
imho, viruses are not truly alive because they cannot reproduce themselves. They rely on the metabolic energy of their host cells, as well as their genetic mechanisms.
What did the parasitic Candiru fish say when it finally found a host? - - "Urethra!!"
I got this from a book. All living things share basic characteristics, including the following:
- Responsiveness - Organisms can respond to changes in the environment, this is called irritability.
- Growth and *most of the time* differentiation - Organisms can grow larger by increasing the number of cells. Individual cells withon the organism become specialized to perform particular functions. In one celled organisms the size of the cell increases.
- Reproduction - Organisms reproduce, creating subsequent generations of similar organisms.
- Movement - Organisms are capable of producing movement, which may be interal or external.
- Metbolism and excretion - Organisms rely on complex chemical reactions to provide energy, this reactions create harmful waste which must be excreated.
Hmm here's all I could find on that stuff I mentioned earlier in the thread:
http://space.newscientist.com/channel/a ... -dust.html
Truth be told, it's all a bit abstract but may interest you.
"What are humans if they don't learn at University? Animals, yes."
^^One of my ex-girlfriends said that. I stress the ex part.
At school, we were taught living things are those that: move, reproduce, react to stimuli, grow, respire, excrete and require nutrition.
But then just as an extra note, someone quipped that fire has all these properties so is this a living thing, blah blah...
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