al@gtx.com (Alan Filipski) (10/17/90)
In article <3610098@hp-ptp.HP.COM> davew@hp-ptp.HP.COM (Dave_Waller) writes: >In article <1097@sun13.scri.fsu.edu> pepke@gw.scri.fsu.edu (Eric Pepke) writes: >}So, the idea that humans were just plopped here, a la Douglas Adams, is >}pretty unlikely. Even if this planet were started from scratch and >}evolution happened again, the chances that it would produce anything >}remotely like a human being are vanishingly small. It might produce >}intelligence and empathy and things like that, but the creature that >}posessed those qualities wouldn't look much like us. > >Why not? It seems to me that starting completely over would produce >creatures generally similar to the ones on the planet today. After all, >most of our gross features are extremely refined adaptations to the >environment around us, and leaving that alone, it seems probable to me >that similar creatures would evolve. I don't buy the "intelligent Well, on a topic as speculative as this, everyone is entitled to an opinion, but I'd suggest S.J. Gould's "Wonderful Life", which argues for the first view above. If I understand him correctly, he says that the evolutionary process has had episodes of radiation (prolific speciation) followed by a rapid decimation (reduction in variety) and that this process has a large almost random or chaotic component to it. The particular course taken depends upon what the particular genetic coding allows, and upon random events in small populations, or the precise state of the gene pool when some catastrophe or global change occurs. I hope I'm not putting words in Gould's mouth, but that was the impression I got from reading the book a few months ago. Comments? [I'll throw this into rec.arts.books, too, just to say that Gould is the best science writer I know, and my small collection of desert island books would certainly include a collection of his essays. If you like science, you've probably read things by him, if you don't think you like science, get one of his collections of essays-- you may be surprised.] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ( Alan Filipski, GTX Corp, 8836 N. 23rd Avenue, Phoenix, Arizona 85021, USA ) ( {decvax,hplabs,uunet!amdahl,nsc}!sun!sunburn!gtx!al (602)870-1696 ) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ God is a comedian playing to an audience that's afraid to laugh.
salem@fritz.sri.com (Bruce B. Salem) (10/18/90)
Two brief comments on this thread: 1) If you are arguing for some kind of Special Creation, whether through supernatural means or by intelligant design from within nature, smart alians, you not only have to single out Man as unique amomg the animals and plants on this globe that presumably evolved without the help of any outside agent, and you have to minimize all the similarities he has with all those organisms. The resolution of this depends on how you look at the characteristics of Man and is easily prejudiced by prior beliefs about Man. Clearly Man's possession of language and consciousness can be used to make him unique in all the world. Further mystify those differences with lots of vague moralistic and religious language and you can blur the issue for a susseptable audience. First, it may be debatable whether Man is unique in having both language and consciousness, it is difficult to communicate with other intelligant animals on earth letalone find out if they have consciousness. This thistinction between Man and the naimals may not be so clearly drawn as recent work with animals and language suggests. If you broaden the scope of the comparison of Man to other lifeforms to Man's biology, a vast number of similarities emerge. Such similarities are very compelling for an evolutionary theory linking all the variation of lifeforms to common ancestory. 2) The course of evolution as explained by S. J. Gould in many places, is that the history of life is an irreversable and unique historical process. Even though evolutionary theory offers a comprehensive account of how the changes could occur, it does not account for pivotal events that shape its course, such as continental or asteroid collisions that interact with biology by causing catastrophic loss of habitats, such as is happing now, and resulting in mass extinctions. These extra-biologic events are serendipitous. The point of Could's remarks is that were it not for the mass extinction event of 65 million years ago that wiped out the Dinosaurs, Mammals might still be confined to rat-like animals and this planet would have long since been inhabited by Little Green Men, with scales. The small preditory Dinosaurs were agile and probably intelligant and their line could have led to characters we ascribe to ourselves, alone, and much sooner than now. Another point made in "Wonderful Life" and elsewhere is that there were biological experiments made at the level of gross body plan for metazoa, at the phylum level, where some plans wone out and flourished in diversity to be large familiar groups, where as others, just as significant lost out, prehaps only by some luck, and became extinct. The Burgess Shale fauna is a record of just such an event. Another worldwide fauna that existed before the Cambrian Explosion had body plans that we would call alian lost out, as well. Bruce Salem