Walking on your hind feet
Dec. 23rd, 2005 02:12 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
mmcirvinThis 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.)
![[identity profile]](https://www.dreamwidth.org/img/silk/identity/openid.png){kind=small}
no subject
Date: 2005-12-23 01:17 am (UTC)no subject
Date: 2005-12-23 02:32 am (UTC)And... yes. I'd never quite put the pieces together that way. It makes some good sense, though.
no subject
Date: 2005-12-23 04:10 am (UTC)You forgot the elbow in permanent-bend-mode-stuck-to-the-face pose as a convenient cell phone holder!
no subject
Date: 2005-12-23 06:17 am (UTC)Schrodinger's Theory of Acquisition of Acquired Characteristics
Date: 2005-12-27 03:40 pm (UTC)Now, if there is ever a mutation that makes an individual more likely to do well in the mountains, he will have a slightly better chance of becoming a mountain-lover than individuals who have no mutation or who have mutations that make mountain-living harder. In time, there will be a higher frequency of mountain-loving genes in the mountains than in the valleys. Because of this, there will eventually become a genetic difference between the two populations.
This mechanism doesn't actually require that there be a survival advantage to having certain characteristics, only that individuals tend to segregate according to that characteristic. So it's a kinder, gentler version of Darwinism, without the tooth and claw and blood.