timw@zeb.USWest.COM (02/22/89)
Thanks for the responses to me query regarding the transfer of instincts and other behavioral traits to succeeding generations through genetics. I'm puzzled. If we agree that an animal is born with certain instinctive characteristics (do we agree on this ?, leave homo sapien out of the picture, whole 'nother topic ?), I contend that genetically defined information determining these characteristics ABSOLUTELY MUST be transferred to the offspring. Where did this information originate ? I don't think it happened overnight. Some salmonid at some point had to have learned that if it didn't swim away from a shadow, it would be Osprey lunch. The Osprey missed this first 'instinct void' fish because it was old and feable. So, unless we're talking creationism vs. evolution, instincts are (1) learned and 2) passed on (IMVHO). Further, I conclude that, a wild, sulf-sustaining population of trout, in a strict catch and release zone, will become very difficult to catch, and when caught will not fight well. In the relatively short term (3 to 4 generations of fish, 8-15 years), these fish will be wary, at the very least, but not necessarily because their parents were wary (of fly-fishermen tactics), but because that group of fish that more pronouncedly avoids fishermen will survive. There WILL be some mortality resultant from our catch and release methodologies. You can't aim a hook at a fish's brain 100 times and expect it not to get hurt. In the relatively medium term (15-100 years), this fishery will be called 'challenging', 'sporting' and 'difficult'. In the case of an extremely pressured (by fishermen) fishery, this population will experience an over-population, since the natural predators have been thinned by human presence. Thus mortality by disease and starvation will increase (cyclic). In the relatively long term (100-10000 years), the fish will become more and more difficult to catch, and will be very poor fighters as it is not beneficial to expend the energy. Sportfishing for trout in this fishery will be extremely difficult and not rewarding. But, what other problems will impact the fishery in the meantime ? Tim Walker Littleton, Colorado
hnewstrom@x102a.uucp (Newstrom Harvey S 96783) (02/23/89)
In article <1681@uswat.UUCP> timw@zeb.USWest.COM () writes: >If we agree that an animal is born with certain instinctive >characteristics (do we agree on this ?, leave homo sapien out >of the picture, whole 'nother topic ?), I am not sure that instinct really exists. (Don't flame me, I'm not sure it doesn't, either!) It may only be a behavior of which we simply do not understand the origins. An example would be the subject of bird migration. It was thought to be instinct that told the bird how to find its way back home because it was felt that visual clues would not be possible. Because we did not understand how the bird found its way, we called it instinct. We now know that birds can navigate using senses that we humans do not have. They can sense their way home about as easily as we can see familiar landmarks to find our way around. Now that we understand it, this aspect of instinct is understood differently. (Note that the way a bird knows _w_h_e_n to migrate is a different question!) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _H_a_r_v_e_y_ _N_e_w_s_t_r_o_m_ _(_h_n_e_w_s_t_r_o_m_@_x_1_0_2_a_._h_a_r_r_i_s_-_a_t_d_._c_o_m_)_ _(_u_u_n_e_t_!_x_1_0_2_a_!_h_n_e_w_s_t_r_o_m_)
hes@ecsvax.UUCP (Henry Schaffer) (02/23/89)
In article <1681@uswat.UUCP>, timw@zeb.USWest.COM writes: > ... > If we agree that an animal is born with certain instinctive > characteristics (do we agree on this ?, leave homo sapien out > of the picture, whole 'nother topic ?), I contend that genetically > defined information determining these characteristics ABSOLUTELY > MUST be transferred to the offspring. ok so far - and so far the word "learn" hasn't been used > Where did this information originate ? I don't think it happened > overnight. Some salmonid at some point had to have learned that ^^^^^^^ ok- here it is - why must it be "learned"? Let us say that I have a flock of chickens and go out and catch one now and then for my dinner. I usually pick a large slow one, and after a suitable time we can see that my chicken flock has turned out to be composed of smaller fleeter individuals than the original flock. Would it be correct to say that the chickens have learned to be smaller and faster? > if it didn't swim away from a shadow, it would be Osprey lunch. ... > So, unless we're talking creationism vs. evolution, instincts are > (1) learned and 2) passed on (IMVHO). Further, I conclude that, ^^^^^^^ if it is not "learned" then the conclusion won't be about learning. > [lots deleted about how fast the population will change] > Tim Walker > Littleton, Colorado The population can change, in response to "selection pressure" regardless of whether or not we call that "learning". (In general I wouldn't call it "learning".) The speed of response depends on the selective pressure and the amount of genetic variation on which the slection can act. --henry schaffer n c state univ
pell@boulder.Colorado.EDU (Anthony Pelletier) (02/25/89)
In article <1681@uswat.UUCP> timw@zeb.USWest.COM () writes: > >So, unless we're talking creationism vs. evolution, instincts are >(1) learned and 2) passed on (IMVHO). Further, I conclude that, > >Tim Walker >Littleton, Colorado I think you are confusing "learning" with selection for those who "know." Now, it is not as simple as that, as I will elaborate. But, given reasonable definitions, no "aquired" or "epigentic" trait can find it's way into the DNA, which is probably the only way in which information is passed on to subsequent generations (Appologies to you Hypotrichus-Cilliate-membrane fans). A mechanism for passage of aquired traits would probably have to work by selection at the protein level for a variant that worked better and then have some "reverse translation" to get back to nucleic acid form. "learned" traits would be more complicated. This seems like a nearly impossible mechanism for several reasons, but I would be remiss not to acknowledge that not long ago, reverse transcription was thought equally absurd. Cases of such Lamarkian inheritence have not been well documented (I don't consider "the case of the midwife toad" to be well documented). Until a mechanism for getting information from the protein level back to the DNA level is found, it is not reasonable--and probably not necessary--to propose such forms of inheitence. What you have described can be explained in more conventional ways (this is not to say the explanation is right), as someone else pointed out. Also, what exactly "instinct" is is debatable. Animals have culture that pass tradition and behaviour on to offspring. For example, the "mother instinct" appears to be maintained as a learned behaviour in mammals. There is an interesting, if not terrible testable, model that asserts that morphological evolution is more visible in "Big-Brain" animals than in stupid animals because learned behaviour that is passed through a population puts pressure on to select for those individuals capable of performing the behaviour. The observation is that in the expanse of time in which humans have come up from ape and countless new bird species have developed, animals like the alligator have remained virtually unchanged. The mutation rate in alligator DNA can be assumed to be on the same order of magnitude as that for mammals and birds, so the difference must be at the selection level. The "environment" in the sense that we usually mean has not changed more for one than the other...the planet has looked alot the same for some time. So some theorists have re-defined environment. Rather than saying the alligator is so well evolved for its environment that any changes are less fit, these people believe that animals capable of learned behaviour change their "environment" all the time so that they create new niches and cause selection for a new trait. For example: a bird is born with a slightly different beak (due to mutation) and tries a new food--a berry it finds easy to get to with its beak. It says "damn, what a good berry. I'll have me some more." Other birds see the bird eating the berry and think "that looks good, I think I'll try one." (I own a bird, believe me they are very imatative). Pretty soon, all the birds are trying it, only not all of them are very good at it. Now, the food supply is not in terrible shortage for them...they won't die out. But these berry-eaters hang out together at the tree and start to breed more often amongst themselves than with others and sooner or later the ones best at eating berrys are doing better in the new niche (i.e., the ones with the best-suited beaks) and lo! a new species is born. Ok, so it sounds a bit absurd; I didn't write it. But there is some circumstantial evidence for it. One of the favorite example in humans that these theorists mention is lactose metabolism. Most adults are lactose intolerent or at least lactase-. There is a (reletively) common mutation in which the juvenile lactase remains functional into adulthood. If you look around Europe for this isotype, you find it is much more common in the Nordic countries. What's the difference? Well, in the South of Europe, you farm; in the North of Europe, you raise dairy cattle, or so the argument goes. I'm not convinced either. But this might be an example of a learned behaviour adding to selection. The problem is you really can't do any experiments on this; you are stuck with correletive studies. But, such a mechanism could explain how a learned behaviour appears to get into the gene pool. -tony
ogil@tank.uchicago.edu (Brian W. Ogilvie) (02/28/89)
In article <1681@uswat.UUCP> timw@zeb.USWest.COM () writes: > >If we agree that an animal is born with certain instinctive >characteristics (do we agree on this ?, leave homo sapien out >of the picture, whole 'nother topic ?), I contend that genetically >defined information determining these characteristics ABSOLUTELY >MUST be transferred to the offspring. More or less, although recombination will affect the specific pattern that the offspring receive. Mutation also plays a part, though it is not as important in the short run as recombination. >Where did this information originate ? I don't think it happened >overnight. Some salmonid at some point had to have learned that >if it didn't swim away from a shadow, it would be Osprey lunch. >The Osprey missed this first 'instinct void' fish because it was old >and feable. > >So, unless we're talking creationism vs. evolution, instincts are >(1) learned and 2) passed on (IMVHO). NO! Instincts are passed on but not learned, at least not in the usual sense of "learned." If an instinct is truly innate then learning has nothing to do with its presence. Let's take your osprey example. If a salmonid learns (because of a couple of close calls, or what have you) to avoid shadows, its offspring are going to be no more likely than the offspring of any other salmonid to avoid shadows. In evolutionary biology's terms, there is selection for a particular behavior, but the behavior is not heritable. An alternate scenario which would produce an increased tendency to avoid shadows would be one where, for some reason, the salmonid avoids shadows due to some predisposition--without ever having seen an osprey. If this behavior is genetically determined, then it is more likely to be passed to the next generation than that of the salmonid which doesn't avoid shadows. In this case, behavior is selected, and since the behavior is heritable it will tend to spread through the population. The difference between the two scenarios is that in one case the behavior is innate (i.e. genetic) and in the other it is learned (or acquired). Under current evolutionary theory there is no way that acquired characters can be inherited. Natural selection acts on random mutation and genetic recombination, not the so-called "Lamarckian" mechanism of the inheritance of acquired characters. The psychologist and biologist James Mark Baldwin did postulate an evolutionary mechanism called the "Baldwin effect" where learned behavior, while not inherited, bought time for natural selection to produce a similar instinct. This mechanism has some subtle flaws. More recently, certain biologists have propsed that many organisms (especially primates) have been selected not for particular behaviors but for the ability to learn quickly and effectively. This is an interesting approach to the problem. A good historical acount of evolutionary theories of behavior is Robert J. Richards, _Darwin and the Emergence of Evolutionary Theories of Mind and Behavior_ (Chicago: University of Chicago Press, 1987). For an overview of the current controversy, Michael Ruse's book _Sociobiology: Sense or Nonsense?_ has been recommended to me, though I mut admit that I haven't read it. E. O. Wilson's _Sociobiology: The New Synthesis_ (Cambridge: Harvard University Press, 1975) is still the definitive text, while Lewontin, Rose and Kamin's _Not in Our Genes_ gives an impassioned presentation of the opposing view. >Tim Walker >Littleton, Colorado -- Brian W. Ogilvie / ogil@tank.uchicago.edu "Cartesianism is the most popular 'popular science' ever invented." --Noel Swerdlow
dmark@cs.Buffalo.EDU (David Mark) (02/28/89)
In article <2035@tank.uchicago.edu> ogil@tank.uchicago.edu (Brian W. Ogilvie) writes: >In article <1681@uswat.UUCP> timw@zeb.USWest.COM () writes: >> >>If we agree that an animal is born with certain instinctive >>characteristics (do we agree on this ?, leave homo sapien out >>of the picture, whole 'nother topic ?), I contend that genetically >>defined information determining these characteristics ABSOLUTELY >>MUST be transferred to the offspring. > >More or less, although recombination will affect the specific pattern >that the offspring receive. Mutation also plays a part, though it is >not as important in the short run as recombination. [some >> lines deleted] >>So, unless we're talking creationism vs. evolution, instincts are >>(1) learned and 2) passed on (IMVHO). > >NO! Instincts are passed on but not learned, at least not in the >usual sense of "learned." If an instinct is truly innate then learning >has nothing to do with its presence. Another mechanism, in at least some organisms, is that they are "hard-wired" to _learn_ certain things from their environments. I know of some examples from birds: young European passerines (song-birds) of some species were demonstrated to not inherit star patterns, but apparently inherit a mechanism for learning the night sky pattern and point of rotation: - adults in fall orient away from the stars about which the night sky appears to rotate, even in a planetarium even when the stars do not rotate. - young birds, exposed to a randomly-generated "night sky" in a planetarium, or to a sky rotating about Orion's belt, later orient to go away from the training rotation point's pattern. bird song. Many species sing the standard song of their species if and only if they are exposed to it at a critical period of their development. Usually, they will not learn the "wrong" song in this period, but also will not develop the correct one without exposure. birds of the year, for both Starlings and White Storks in Europe, appear programmed to migrate a certain distance and direction. From Denmark, storks normally winter in Spain, and starlings in UK. Adult and young birds were trapped in autumn in Denmark, and released in Poland. The adults turned up where they were supposed to, but the young ended up in Turkey (storks) or France (starlings), respectively, the correct distance and direction but the wrong start point. In this case, the instructions were apparently innate, but the "map" had to be learned. Finally, I recently heard, somewwhere, that human babies react to lots of sounds in their first week or two, but then reduce greatly their reaction to sounds *not* in the language that they hear, but react more to the phonemes of the language(s) around them. A hard-wired procedure for selectively learning only relevant parts of the sensory environment may be important. [I can probably find references for the bird stuff if required] David M. Mark dmark@cs.buffalo.edu