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Author Topic:   The Sex Life of 747 Aircraft
Modulous
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Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 48 of 84 (408560)
07-03-2007 12:44 PM
Reply to: Message 46 by anastasia
07-03-2007 12:02 PM


Is there something in the nature of life that causes reproduction, and why would this evolve rather than continuation or regeneration of the same organism?
If such an organism was ever to exist it would never die of old age and it would never reproduce. It would instead be killed by predators, parasites, diseases, accidents or disasters (organisms seldom die of old age anyway so it would make very little difference). The genes that made the organism non reproductive but able to be old aged would not get passed on and that would be end of it.
Genes that make many copies of themselves become more numerous than genes that don't make as many copies. Clearly genes that don't reproduce at all are doomed to extinction in one generation. The first order of the day for genes then is to reproduce. There are various strategies that have evolved for this task, but there are two main ones: sexual and asexual. Seed bearing plants can be both, (they will sometimes 'ejaculate' the male pollen to reach their own female ovule).
The one thing which I have trouble with in the survival 'goal' is seed bearing plants.
The goal isn't 'survival'. There is certainly a strong pressure to survive, but that pressure only needs to last until an organism has reproduced sufficiently and in some cases raised the subsequent offspring. After that, there is little to no survival selection. We see that in nature, some species die soon after mating. There are other pressures that come into play: sexual selection being the most obvious.
Producing seeds isn't a survival advantage for the plant itself (necessarily), but it is a survival advantage for the plant's genes. They get transferred to the offspring and the genes 'live' a little longer.

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 Message 46 by anastasia, posted 07-03-2007 12:02 PM anastasia has replied

Replies to this message:
 Message 49 by anastasia, posted 07-03-2007 3:32 PM Modulous has replied

  
Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 62 of 84 (408708)
07-04-2007 7:25 AM
Reply to: Message 49 by anastasia
07-03-2007 3:32 PM


Would you speculate that at one time, non-reproductive species existed, or would you say that reproduction is truly the order of the day? And if so, you didn't quite answer my question.
I don't think it is possible for a non-reproductive species to exist. The occasional individual, perhaps a family...but a species? I can't even begin to speculate how that would ever happen. Of course there are plenty of species that at one time didn't get to reproduce that went extinct - but species are a classification of life and the entire purpose of creating organisms is to serve as vehicles that propagate genes so a non-reproducing species seems to me to be the height of impossibility.
Things either survive, or don't. Survival seems to be the goal, but perhaps it is only the accidental result?
As I said - survival is the goal of genes. Organisms only need survive long enough to propagate those genes.
What I am asking is, even if you could say that survival 'pressures' are evolved as part of a species and continue to be part of their make-up, how would we explain the 'desire' of the first living thing to reproduce? Is there some gene which designates this drive?
Life is replication. The first thing that lived replicated itself. If it didn't replicate itself there are no other characteristics it would have that could have itself recognized as living. It would have just been organic chemistry. It was replication along with inheritance of traits that defined the beginning of life.
There was no 'desire' to reproduce, it is just that the first thing that reproduced and passed on that property to its offspring would have been the first thing we would be tempted to call life. Naturally its offspring would also have the reproduction property and so they would reproduce. If any of the resulting offspring lost the technique of replication that line would go extinct.
I'm sure in in modern complex life there are many genes that have been perfected to increase the chances of reproduction. One could almost say that is the entire use of all genes. Some genes aid in reproduction by increasing the chances of the organism in surviving predator attack, some aid in reproduction by increasing the chances of the organism surviving to find sufficient food and some aid in attracting mates.
As for the 'sex drive', in more complex animals, I'm sure there are genes that control the brain which is the thing that makes the decisions about how to prioritize time, and the parts that say 'we should mate now' have undoubtedly got a team of genes behind them.

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 Message 49 by anastasia, posted 07-03-2007 3:32 PM anastasia has not replied

  
Modulous
Member
Posts: 7801
From: Manchester, UK
Joined: 05-01-2005


Message 66 of 84 (408828)
07-05-2007 6:47 AM
Reply to: Message 63 by anastasia
07-04-2007 11:32 AM


function
The un-scientific amoung us are just blown away that something could produce any function without planning it.
Which is fair enough. The more scientific among us are happy to show examples of this happening in front of our eyes. We just need to look at evolutionary algorithms. Without any planning, and much to the researcher's delight, a physical evolutionary algorithm designed a radio, or using simple chemistry a pseudo-ear was formed (described in the same paper).
The scientific among us are blown away too by the wonderful power of evolutionary systems and the wide array of uses that nature finds for collections of chemicals. Awe-inspiring.

This message is a reply to:
 Message 63 by anastasia, posted 07-04-2007 11:32 AM anastasia has not replied

  
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