colby@bu-bio.bu.edu (Chris Colby) (12/19/90)
In article <37034@cup.portal.com> mmm@cup.portal.com (Mark Robert Thorson) writes: >The professor of the course had a table summarizing many experiments with >other species, showing a rise in information transfer as you go up the scale >to humans, who (by this measure) can assimilate hundreds of bits per second. Mark, I liked your post but I cringed when I read the above. The idea that evolution is a linear scale with humans at the pinnacle is simply not true. Other animals are not "lower" animals as you call them, just divergent. For example, chimps are the most closely related species to us. But, they are not a lower species. We did not evolve from chimps, we share a common ancestor with them. If you look at the topography of evolutionary history, you will see it resembles a tree or bush. Each extant species at the tips coalescing back into the ancestral species they diverged from. From a single common ancestor life multiplied and species diverged into many branches. It was not a march of progress with human beings being the goal. Extant (living) species are not our ancestors, we share a common ancestor with them. they have been evolving right along with us. The idea of evolution as a scale probably come from people wanting to view evolutionary change as progress. Evolution is not progress. It is just change. Organisms adapt to their current environments and that's it. Humans may be the most intelligent species on the planet, but we are not the pinnacle of evolution. Chris Colby email: colby@bu-bio.bu.edu
chappell@willy.uchicago.edu (Chappell) (12/20/90)
S.J. Gould is an advocate of this view of life (that it is not an orderly succession from bacterium to Republican), and presents it as a theme of his recent book "Wonderful Life". It is an interesting, though characteristically somewhat bombastic, description of the Burgess Shale and its implications to evolutionary theory; stars Jimmy Stewart and sundry unheard-of phyla. Rick Chappell.
kingsley@hpwrce.HP.COM (Kingsley Morse) (12/21/90)
/ hpwrce:comp.ai / colby@bu-bio.bu.edu (Chris Colby) / 7:43 pm Dec 18, 1990 / >The idea that evolution is a linear scale with humans at the pinnacle >is simply not true. > >From a single common ancestor life multiplied and species diverged into many >branches. I'm interested in evolution, and applying it to AI. I've been assuming that evolution is goal directed, in a sense. I'm interested in feedback on my assumption. Do you think it's possible that Darwin's theory of natural selection uses "fitness" as a goal? In other words, Darwin proposed that "survival of the fittest" causes succeeding generations to be ever better adapted to the environment. Could successively fitter generations be considered a "scale", in that any given branch of evolution has "fitter" genes at it's leaves than at the root?
mikeb@wdl31.wdl.loral.com (Michael H Bender) (12/22/90)
In article <70996@bu.edu.bu.edu> colby@bu-bio.bu.edu (Chris Colby) writes:
Mark [Mark Robert Thorson],
I liked your post but I cringed when I read the above.
The idea that evolution is a linear scale with humans at the pinnacle
^^^^^^^^^^^^
is simply not true. Other animals are not "lower" animals as you call
them, just divergent. ....
First a nit: the terms "higher" and "lower" don't require a linear scale, a
partial ordering is sufficient. It is quite possible to define a partial
ordering on the evolutionary tree -- it just means that not every two
points on tree are comparable (only if they are on the same branch).
However, the real point is that there is an anthropormorphic tendency to
define different metrics which can be applied to the evolutionary tree and
which do provide linear scales. Isn't it a surprise that these metrics,
developed by humans, always show humans on the top of the scale?!
Putting aside Teleolgoical questions, I think that the metric which
measures the rate at which an organism can receive and process information
is a very fascinating one and worthy of discussion/debate.
A different metric which I have also heard of defines the concept of "free
will" as the range of different behaviors that an organism may show to the
same stimulus. It has been claimed that animals like humans and the apes
show much more free will than ants or rats. Although I don't know of any
easy way of measuring "free will", I find it an intriguing concept.
Mike Bender thornley@cs.umn.edu (David H. Thornley) (12/22/90)
In article <70996@bu.edu.bu.edu> colby@bu-bio.UUCP (Chris Colby) writes: >In article <37034@cup.portal.com> mmm@cup.portal.com >(Mark Robert Thorson) writes: > >>The professor of the course had a table summarizing many experiments with >>other species, showing a rise in information transfer as you go up the scale >>to humans, who (by this measure) can assimilate hundreds of bits per second. > > Mark, I liked your post but I cringed when I read the above. >The idea that evolution is a linear scale with humans at the pinnacle >is simply not true. Other animals are not "lower" animals as you call >[Summary: The evolutionary pattern is a tree, with various species > splitting off and continuing to evolve on their own.] > > The idea of evolution as a scale probably come from people >wanting to view evolutionary change as progress. Evolution is not >progress. It is just change. Organisms adapt to their current >environments and that's it. Partly true. However: Here-and-now, it is about 0 degrees Fahrenheit (that's -17 or so to you Celsius fans) with heavy falling and blowing snow. You could say that I have adapted to the current environment by buying a house with a furnace, and heating it to 68 F (about 20 C) and using walls to keep the wind out. You could also say that I haven't adapted to the environment at all, but rather that I changed it. Only a very few organisms adapt their environments in such a way, and most of those who do use fairly primitive means and do not adapt as well as humans to varieties of conditions. Furthermore, humans are the only species I am aware of that is capable of transmitting experience without physical presence. On these two grounds, I conclude that humans are, in a very real sense, not just another species. > > Humans may be the most intelligent species on the planet, >but we are not the pinnacle of evolution. > Various types of critters can be looked at as pinnacles, depending on what you are looking for. For intelligence, humans. For sheer ability to live in adverse conditions, cockroaches or something. For causing ecological disasters, I think you'd have to go with those ancient things (plants?) that totally changed the Earth's atmosphere from a reducing atmosphere to an oxidizing one, and killed most of the existing life- forms. DHT
maguire@sun.soe.clarkson.edu (Bill Maguire) (12/22/90)
>/ hpwrce:comp.ai / colby@bu-bio.bu.edu (Chris Colby) / >7:43 pm Dec 18, 1990 / >>The idea that evolution is a linear scale with humans at the pinnacle >>is simply not true. >> >>From a single common ancestor life multiplied and species diverged into many >>branches. In article <1870014@hpwrce.HP.COM> kingsley@hpwrce.HP.COM (Kingsley Morse) > writes: >I'm interested in evolution, and applying it to AI. I've been assuming that >evolution is goal directed, in a sense. I'm interested in feedback on my >assumption. >Do you think it's possible that Darwin's theory of natural selection uses >"fitness" as a goal? In other words, Darwin proposed that "survival of the >fittest" causes succeeding generations to be ever better adapted to >the environment. Could successively fitter generations be considered a > "scale", in that any given branch of evolution has "fitter" genes at it's >leaves than at the root? As one of the earlier posters suggested, read Gould's books. Fitness for an environment depends on that environment. Over the years a species' environment is in a constant state of change because of a number of factors. Among them continental drift (i.e. a continent moving closer or farther from a pole), the cycle of ice ages, earthquakes, volcanic activity, etc. Species adapt (evolve) to fit the changing environment. When the environment changes the ones that are most able to survie in that environment fare better and pass their genes along. Whether this happens fast or slow is discussed in several of the chapters in Gould's books. He is interesting to read. Thus evolution might be "goal directed" but the goal is constantly changing. You can't say that a species at a leaf is more fitter than a species at an earlier node, because the context has changed. We do not live in the environment that existed millions of years ago. The species now might be more fitter for the current environment, but who knows how well it would fare if it time travelled back to it's ancestors environment. Bill Maguire maguire@sun.soe.clarkson.edu She had so many chins she looked like a piece of lisp code :-)))))))
dave@tygra.ddmi.com (David Conrad) (12/22/90)
In article <1870014@hpwrce.HP.COM> kingsley@hpwrce.HP.COM (Kingsley Morse) writes: > >Do you think it's possible that Darwin's theory of natural selection uses >"fitness" as a goal? In other words, Darwin proposed that "survival of the >fittest" causes succeeding generations to be ever better adapted to >the environment. Could successively fitter generations be considered a "scale", >in that any given branch of evolution has "fitter" genes at it's leaves than >at the root? Certainly the process of natural selection tends to produce creatures which are better adapted to their environment, but it must be remembered that the environment is not a constant. There is a theory which postulates that the Earth had, at the time life emerged, an atmosphere consisting of perhaps methane, who knows what else, and little oxygen. (Obviously I am not an expert in these matters, and I don't know the current status of this theory.) Assuming that the environment of the Earth at that time consisted of this so-called Primordial Soup, it would be naive to suggest that we humans are "fitter" (read: better adapted) for that environment than the creatures alive at the time were. Indeed, were you or I to time travel to that period we would asphyxiate and expire in short order. My point, essentially, is that a creatures "fitness" can only be judged w.r.t. its environment, which is variable (albeit over large time frames, unless global warming is correct, in which case we find out just how quickly we can adapt). Regards, David R. Conrad | "Playing at the hard-case, you follow the example of dave@tygra.ddmi.com | the comic-paper writer, who lets you bend the rules." ...!uunet!tygra!dave | -- Jethro Tull, _Thick as a Brick_ -- = CAT-TALK Conferencing Network, Computer Conferencing and File Archive = - 1-313-343-0800, 300/1200/2400/9600 baud, 8/N/1. New users use 'new' - = as a login id. AVAILABLE VIA PC-PURSUIT!!! (City code "MIDET") = E-MAIL Address: dave@DDMI.COM
poirier@ellerbe.rtp.dg.com (Charles Poirier) (12/28/90)
In article <1870014@hpwrce.HP.COM> kingsley@hpwrce.HP.COM (Kingsley Morse) writes: >/ hpwrce:comp.ai / colby@bu-bio.bu.edu (Chris Colby) / 7:43 pm Dec 18, 1990 / > >>The idea that evolution is a linear scale with humans at the pinnacle >>is simply not true. > >I'm interested in evolution, and applying it to AI. I've been assuming that >evolution is goal directed, in a sense. I'm interested in feedback on my >assumption. > >Do you think it's possible that Darwin's theory of natural selection uses >"fitness" as a goal? In other words, Darwin proposed that "survival of the >fittest" causes succeeding generations to be ever better adapted to >the environment. Could successively fitter generations be considered a "scale", >in that any given branch of evolution has "fitter" genes at it's leaves than >at the root? "Fitness" can not be defined in isolation; one is only "fit" with respect to a given environment. The poster's point of view would be fine, were it not for the fact that the environment itself is continually changing. Bear in mind that the "environment" includes other living, and thus evolving, creatures. Climate and terrain are other factors that vary over time. I expect that if today's species could be somehow transported to a past era, that some (perhaps many) would be less fit *for that environment* than their forebears who evolved for fitness in that world. If so, we can't claim consistent progress toward an idealized goal of "fitness". We lack a good crystal ball to tell us the shape of some future environment; so we can't say whether or not the current environment directs current natural selection toward future fitness. In short, evolution is not goal-directed because the goal does not exist. Of course, there is continuity as well as change. One could attempt to abstract those aspects of the environment that remain relatively constant over a given span of space and time, and claim that natural selection is directed towards the goal of fitness to survive and reproduce in that (abstract) environment. But this is a slippery concept. One might counter that the local environment of every individual is unique in some way, implying a multitude of distinct goals: one for each creature. One is then stuck with the unsatisfying image of each and every living thing as the pinnacle of a chain of length one. Cheers, Charles Poirier poirier@dg-rtp.dg.com