Universal Evolution

[mrcurious]

There are all types of planets in our universe and scientist are finding them everyday. But an even bigger, the search for life, on these planets would be one of the greatest discoveries in history.<br /><br />If we find another Earth, lets call it Earth 2. Earth 2 has all the same conditions as our Earth, on that scale there isn't any different. So the same elements that make up our life would also be the same elements involved in the development of life on Earth 2. <br /><br />So would the same types of lifeforms be present on Earth 2? Of coarse, life being highly adaptable would mean their would be differences, but on a more general scale, would life be the same as ours? Are the current species of life the ultimate eventualilty of billions of years evolution on every earth like planet in the universe?<br /><br /><br /><br /><br /><br />

 

[derekmcd]

My first thought on this is, yes... But only such that they would be carbon based lifeform with some remotely similar tools adapted for survival in their environment.<br /><br />The earth has undergone several dramatic extinction events that have steered the course of evolution for the currently existing species. The odds that your Earth2 having dealt with these same events is quite unlikely.<br /><br />Also, random genetic mutation is just that... random.<br /><br />I guess my point is finding lions, tigers and bears (oh my) on a planet similar to ours is quite improbable (though, not impossible). <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[mrcurious]

<font color="yellow">random genetic mutation is just that... random.</font> <br /><br />Good point.<br /><br /><font color="yellow">The earth has undergone several dramatic extinction events that have steered the course of evolution for the currently existing species. The odds that your Earth2 having dealt with these same events is quite unlikely.</font> <br /><br />I forgot to take that into account.....there have been 5 major mass extinctions which shaped life on earth. So life on earth is very resilent and unique. <br /><br />

 

[derekmcd]

There are so many variables. A couple more major ones include the tidal effects of our moon and the tilt of the Earth's axis.<br /><br />I feel compelled to mention the butterfly effect. One minor event 2 billion years ago could very well change the course of the Earth biological history.<br /><br />So, yes... I agree. Life on Earth is very resilient and quite likely very unique. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[oscar1]

All fair and well, but the word (and our interpretation of it) 'unique' only applies to our [relatively] small environment. We do know for a fact that there is life in the universe, because we are here. We also know for a fact that life, once it has begun, cannot be wiped out by anything that happened on and to the Earth since life began, and adapts rather well to changing circumstances. Heck, we can even safely assume that we will be able to leave Earth long before the Sun enters its final fase (if we do not destroy ourselves that is, but that is not relevant here). So I would imagine that if the cards are dealt such that life begins, and the planet and the solar system it finds itself in do not undergo something really dramatic, that that life will reach the stage of conciousness/intelligence. Afterall, we know no else but that nature directs this, or at least does not disallow it, despite the set-backs during the process.

 

[derekmcd]

"<i>All fair and well, but the word (and our interpretation of it) 'unique' only applies to our [relatively] small environment.</i>"<br /><br />I'm not exactly sure what your point is with this statement. I used the term unique in reference to, what I believe, MrCurious' intended question was. Unique in that, after billions of years of evolution, many variables steer the course of evolution. Unique in physical characteristics and genetic make-up. Walking upright with opposable thumbs is not a requirement for intelligent life.<br /><br />I do not believe that conscious, intelligent life is, necessisarily, a natural course of evolution. Of the several million species of life on earth, only a very, very small number have achieved this status.<br /><br />Had the dinosaurs not become extinct, would the human race arisen? We simply do not know. I think it is safe to state, though, that it is not an inevitability that we would have anyway.<br /><br />I do believe that primordial lifeforms could be quite similar on "Earth2", but the variables are too many to state that intelligent life is inevitable.<br /><br />There could be a million Earth2s out there, but there are millions of variables over the course of billions of years of evolution that nature could direct. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[oscar1]

Where 'unique' is concerned, what I meant is that 'out there' there are at least some 200 mio. galaxies with at least 100 mio. stars in each (not mentioning the factor synchronisation). This offers such a literally astronomical number of possibilities that it makes our 'local' word 'unique' rather humble in comparison. <br /><br />You could be right in that intelligent life may not necessarily be a natural cause, yet it is quite natural that one (a species in this particular case) becomes the leader and holds down any possible competition. In other words, out of no matter how many species, there will likely only be one that has reached the intelligent level.

 

[derekmcd]

I understand, now, your definition of unique. You are using one of the bases of the Drake Equation. They are <i>only</i> possibilites, however. I would add, that of those "astronomical number of possibilities" of earth-like planet that harbor life, there are an astronomical number of variables that will steer the evolution of that system. And that's <i><b>my</b></i> definition of unique.<br /><br />As for intelligent life, I believe you are defining intelligent as human level intelligence (correct me if I am mistaken). I'm compelled to agree with you in that should two or more species achieve HLI, competition for resources would eliminate those with even the slightest of disadvantages. Homo-sapiens are a clear case of that.<br /><br />My point back to the original thoughts on Universal Evolution, however is such that even the entire family tree from which homo-sapiens sprang forth is immensly tiny compared to the overall number of species on this planet. <br /><br />Of all the (in my best Carl Sagan voice) "billions and billions" of variables, the scenario that allowed for the human race can not be scripted and quite likely can not be duplicated. <br /><br />I'm certainly not precluding intelligent life elsewhere in the universe... I, actually, think it is quite likely. But their path of evolution will likely be far, far different than ours. <div class="Discussion_UserSignature"> <div> </div><br /><div><span style="color:#0000ff" class="Apple-style-span">"If something's hard to do, then it's not worth doing." - Homer Simpson</span></div> </div>

 

[mrcurious]

<font color="yellow">There could be a million Earth2s out there, but there are millions of variables over the course of billions of years of evolution that nature could direct.</font><br /><br />Thats an endless supply of lifeforms. If there are other "opportunistic" planets out there I do believe life is on them.

 

[dragon04]

Life and evolution are probably two discrete issues.<br /><br />I'm of the belief that life is common in the Universe. In our galaxy alone, there are likely at the least, hundreds of millions of planets. Not a few hundred, thousand, or tens of thousands, but hundreds of MILLIONS.<br /><br />It seems unlikely to me that Earth would be unique out of hundreds of millions of worlds to harbor life, or the conditions for life to exist.<br /><br />Further, carbon based life is the <b>easiest</b> life to work out. And there's lots of Carbon out there. There's also lots of water out there. Carbon+Water+Energy = Hydrocarbons.<br /><br />Energy isn't a problem either. The Universe has lots of that.<br /><br />But now to your question. To answer, I have to ask a question, unfortunately.<br /><br />What's the <b>easiest</b> path to life, be it single celled, or sentient?<br /><br />That's really where the debate starts, IMO. Undoubtedly, as others have pointed out, evolution of life likely requires random, catastrophic events to move to the next better thing. Adaptation is a key to Evolution. "Static" conditions would not be the friend of any Evolution, I think.<br /><br />The issue of advanced life is subject to many factors. Single celled, or more "simple" life requires less factors, I think.<br /><br />While we can't know how life evolves beyond our Earth, I would think that chemistry found the easiest path possible to create life here on Earth.<br /><br />And seeing that it happened very early in our planet's history, it's done in very short order if the conditions are right.<br /><br />I personally live somewhere in between the anthropomorphic view unique to our biosphere, and the opposing notion that any life we encounter will be wildly different from what we know.<br /><br />I think the biggest differences would be in appearance as opposed to function. I would think that any complex life form anywhere in the Universe would have a great deal in common with lifeforms on Earth.<br /><br />The would h <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[vandivx]

<font color="yellow">Most species on Earth that have eyes have two eyes, for example. Why not 5? The only answer that I can provide is that here on Earth, two-eyed, stereoscopic vision ended up being the most adaptable form. But not just because that was best for any species to survive.</font><br /><br />you say 'here on Earth'... I say that two eyes will be standard on Earth2 as well, reason being that it is the minimum for stereoscopic vision, same for two ears, nature is functionally minimalistic in design, that's why we have two eyes and ears but only one nose<br /><br />as a handyman in my spare time I often wish for third hand (like you hold can of paint in left, paint brush in right and with the third hand you hold the bushes off the house siding while you paint <img src="/images/icons/smile.gif" /> ), alas the universal stock equipment nature provides is four limbs for animals because that is best for universal locomotion to start with and from there some creatures develop/atrophy couple front limbs usually and change them to wings or hands if they start walking upright but the basic start is four limbs for most creatures (it probably started with fins)<br /><br />I think that survival based evolution is just one, perhaps small aspect of evolution at that, that there are other reasons than survival advantage for why we are as we are<br /><br />what I am saying is don't expext three or more eyed or handed ETs or three stock limbs (same for one eyed...), I think if we ever find ET life forms they will be just variation on the life on earth and that will provide enough variety anyway as it is but the fundamentals will be very likely the same<br /><br />I believe what is most likely will happen, that's how nature evolves, that means that I do not see life on Earth as some odd chance development that could have happened other way(s) - I mean in essential ways - and I expect that life on Earth2 while being totally different in non essentials will be very much the s <div class="Discussion_UserSignature"> </div>

 

[dragon04]

<font color="yellow">you say 'here on Earth'... I say that two eyes will be standard on Earth2 as well, reason being that it is the minimum for stereoscopic vision, same for two ears, nature is functionally minimalistic in design, that's why we have two eyes and ears but only one nose</font><br /><br />I don't disagree at all. However, for the time being, I only have one frame of reference by which to make any supposition, and that's not enough for me to phrase things differently.<br /><br />A case in point would be spiders. They've done quite nicely, evolutionarily speaking with 6 or 8 eyes. There's no reason to believe that Earth2 might be inhabited ubiquitously by 6 or 8 eyed life forms.<br /><br /><font color="yellow">what I am saying is don't expext three or more eyed or handed ETs or three stock limbs (same for one eyed...), I think if we ever find ET life forms they will be just variation on the life on earth and that will provide enough variety anyway as it is but the fundamentals will be very likely the same</font><br /><br />Generally speaking, I'm inclined to agree. Pairs of eyes and ears, and 4 extremities in various combinations have been very successful here on Earth1. As have 2 eyed creatures with 6 extremities. Or even 8 or 10 counting the octopus, squid and cuttlefish.<br /><br />However, that doesn't preclude the possibility of more exotic life forms being the rule as opposed to the exception on any given life bearing planet.<br /><br /><font color="yellow">also doubt that we will ever come accross life forms based on anything other than carbon</font><br /><br />This I agree with to almost total certainty. Carbon allows the easiest, most economical path to the genesis of life AFAIK.<br /><br />To me, the "path of least resistance" would be a Universal principle. Everything we know follows it. Water, electricity, air, etc.... Why would the genesis of biology be any different?<br /><br /><br /><br /><br /><br /> <div class="Discussion_UserSignature"> <em>"2012.. Year of the Dragon!! Get on the Dragon Wagon!".</em> </div>

 

[vandivx]

your mind is a bit too open for my taste<br /><br />I see those creatures you mention as examples of more eyed and more legged as accidental relics or oddities left over from the times when nature made some accidental mutations some of which took hold and managed to survive till today with non near end to them in view<br /><br />it would seem that those extra eyes, leggs or whatever didn't provide significant survival advantage, else those creatures would take over the Earth but they didn't, probably there were more such odd animals in the early days of evolution (I suspect nature started with various numbers through mutations and settled on couple in the end) but most didn't survive and some simply did survive perhaps being lucky and that's that<br /><br />having more eyes than couple can't hurt and likely they don't provide much of a survivor advantage as vitness zillions of other animals that get by just fine with two (I know you would agree, its not like like I argue against you, just muling it over for myself)<br /><br />more eyes than are really necessary eat up brain processing power and the more advanced animal the less it can afford to waste what it has, couple eyes are most economical for what they provide and the processing of the sensory input from two channels while way more complicated then if there was just one channel is well worth it and more channels than two would be really redundant IMO even if we could muse over the utility couple more eyes or at leat one on the back of our heads would give us (like for teachers in schools) nature just doesn't take such things into consideration, same as my wishing for third hand, I don't think that we will ever grow third hand no matter how handy that would be for that house painting <img src="/images/icons/laugh.gif" /> again think of the processing it would take to coordinate the motion of an additional limb (I also suspect that it is easier for our brain to coordinate even number of eyes or limbs or ears than odd numb <div class="Discussion_UserSignature"> </div>