Video of the day -- the meaning of life
What differentiates the living from the non-living? The boundaries between the two are fuzzier than one might think. "Life" is basically the name we give to chemistry when it exceeds a certain level of complexity and takes on certain characteristics. Differences in magnitude can mean differences in kind (an ocean differs from a glass of water in ways that can't be deduced merely by scaling up the observable traits of the latter), but ultimately life as we know it is just a complex form of chemistry.
Life on another planet, where evolution had proceeded along different lines, might be difficult for us to identify or define. And as artificial intelligence comes into its own, we will probably have to deal with self-awareness in forms which are not "alive" as we currently define it.
AronRa's channel is here; my earlier post about him is here.
posted by Infidel753 at 9:00 AM
3 Comments:
That was a very informative, well-produced instructional video. It covers all the material I teach my biology students, although it's a bit too basic and too long for the more advanced students I teach during the summer. I like that it makes the same point I do about viruses; they're life that isn't actually alive. As for zombies, I'm glad that the answer was "just kidding." If Aron Ra had been serious, I could go on for another paragraph! That's what happens when one becomes a zombie expert.
AronRa is a knowledgeable guy and a valuable voice. I've often wondered about viruses -- they don't meet all the criteria for being alive, but they use chemicals that are characteristic of life, like DNA or RNA. I suppose they must have evolved from more complex, genuinely living things which actually became simpler to adapt to the presence of real cells they could parasitize.
I wondered about zombies too. Since they eat, they must metabolize, and they're certainly cellular. They probably don't develop and grow, but they respond to stimuli. They don't seem likely to reproduce, but I've heard of that in some of the more pervy Japanese films on the subject. I'm not sure if their limited range of behavior counts as adapting to the environment, but they presumably maintain some kind of homeostasis since they can stay active for days. So I guess they're a marginal case.
"I suppose they must have evolved from more complex, genuinely living things which actually became simpler to adapt to the presence of real cells they could parasitize."
That's the leading hypothesis about their origin that I've read, so you're most likely right.
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