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Walking on your hind feet
Dec. 23rd, 2005 02:12 amThis article on the secret (and unsuccessful) Soviet human-chimp hybrid experiment mentioned the peculiar and sometimes sad tale of Oliver the bipedal chimp, who I vaguely remember reading some slightly woo-woo stories about years ago (turns out he's just a genetically ordinary chimp who likes to walk upright, for no particular reason anyone knows).
But in connection with Oliver's unusual walk, it also points to an earlier, fascinating article on an idea I'd heard some mentions of previously and have only recently been wrapping my head around: that major changes in the bodies of organisms might be largely driven by developmental plasticity. The leading proponent of the idea is Mary Jane West-Eberhard, who thinks this is one of the major mechanisms of evolution.
When animals behave in a novel way throughout their lives, such as quadrupedal animals who have to walk on two legs because of injury, this can affect their development in such a way as to cause what look like radical anatomical rearrangements without any genetic change at all. If a whole population of animals were to start behaving differently from infancy, say hobbling around on two legs or changing their diet as a result of some environmental change or social transmission of behavior, that could physically change them within a single generation.
Biologists know today that this won't immediately cause any genetic changes in the animals' offspring. But over multiple generations of the animals behaving differently, it could even eventually have genetic effects! The reason is that genetic changes that happen to aid the new things everyone is doing, in the physical configuration in which everyone now grows up, would suddenly be good for survival, altering the natural selection determining what genes get preferentially passed on to the next generation. It's like a sort of a slow-motion Lamarckian evolution happening through the effect of behavior on the body and in turn on Darwinian selection pressures. Eventually the old way of living might not even be possible any more (though new realms of possible plasticity would themselves be opened up).
I conclude that our distant descendants will be obliged to live entirely on Coca-Cola and Cheetos and will be able to sit in one place for a year without their butts losing circulation. (Cue ancient Mad magazine pictorial on the future of the motor scooter.)
But in connection with Oliver's unusual walk, it also points to an earlier, fascinating article on an idea I'd heard some mentions of previously and have only recently been wrapping my head around: that major changes in the bodies of organisms might be largely driven by developmental plasticity. The leading proponent of the idea is Mary Jane West-Eberhard, who thinks this is one of the major mechanisms of evolution.
When animals behave in a novel way throughout their lives, such as quadrupedal animals who have to walk on two legs because of injury, this can affect their development in such a way as to cause what look like radical anatomical rearrangements without any genetic change at all. If a whole population of animals were to start behaving differently from infancy, say hobbling around on two legs or changing their diet as a result of some environmental change or social transmission of behavior, that could physically change them within a single generation.
Biologists know today that this won't immediately cause any genetic changes in the animals' offspring. But over multiple generations of the animals behaving differently, it could even eventually have genetic effects! The reason is that genetic changes that happen to aid the new things everyone is doing, in the physical configuration in which everyone now grows up, would suddenly be good for survival, altering the natural selection determining what genes get preferentially passed on to the next generation. It's like a sort of a slow-motion Lamarckian evolution happening through the effect of behavior on the body and in turn on Darwinian selection pressures. Eventually the old way of living might not even be possible any more (though new realms of possible plasticity would themselves be opened up).
I conclude that our distant descendants will be obliged to live entirely on Coca-Cola and Cheetos and will be able to sit in one place for a year without their butts losing circulation. (Cue ancient Mad magazine pictorial on the future of the motor scooter.)