I disagree. The introduction of random, non-adaptive mutations is more meaningfully called devolution than “evolution due to a different set of selection pressures.” It is not due to selection pressures. “Devolution” means that deleterious mutations are accumulating faster than they are selected against.
They are deleterious only as judged by our value system, they are adaptive for the organism. Please note that “adaptive” and even “deleterious” have technical or semi technical meanings as well as the more “common sense” ones.
Artificial lifeforms like the use employed explicitly clarified thank you very much.
Note: Retracted. Seems I was a sloppy reader. See comments below.
No—look, evolution is the fixation of random mutations. Most mutations are not adaptive! The vast majority are either neutral, or destructive, often rendering a protein nonfunctional.
When selective pressure is high, bad mutations are eliminated, and good mutations increase in frequency. When selective pressure is low, bad mutations are introduced much faster than good mutations.
You can’t simultaneously believe in evolution, and not believe in devolution, unless you have a mystical view of evolution as something that magically always adapts.
Artificial lifeforms like the use employed explicitly clarified thank you very much.
I don’t have any real disagreements with the points you make there, but I do think this statement could mislead some:
Provolution—has led gradually from primitive simplicity to the powerful adapted complexity of modern living things
Loss of complexity can certainly be adaptive too, as I think you acknowledge here:
What about a cave fish losing its sight? Is that devolution? If it is losing its eyes because doing so saves energy and is adaptive—which is quite likely—that would not be devolution in the sense described here.
Also, interesting to note that one cave fish, Astyanax, seems to have lost its eyes not to conserve energy, but because of pleiotropy: the same genes used in eye development are also involved in other traits, like sense of taste, and mutations which produce improvements in taste simultaneously change eye development. It’s hazardous to talk about the fuction of something before you know how it’s made!
Ah I see the source of the misunderstanding. I was fixating on altruism and its adaptive value of lack of there of, in my mind I was challenging characterising the reduction of altruistic behaviour as devolution.
You however where speaking generally of human devolution and even defining the concept for the reader’s benefit!
You are of course right.
If I could sleep I would excuse myself as staying up way to late in this time zone. However I can’t do that. Please accept a delicious slice of cake as apology.
You are kidding me. Did you just say that mutations-reaching-fixation-we-know-they-weren’t-selected-for should be classed as mutations-reaching-fixation-and-adaptive-for-the-organism? That has got to be the dumbest thing… [head explosion].
But low capacity for altruism is selected for in the environment discussed.
Any genetic change due to selection (I doubt nature makes the pretty distinction between natural and artificial selection as clearly as we do) that eliminates an undesired trait or characteristic is basically by definition adaptive and not deleterious (as in harmful, injurious to the organism).
I disagree. The introduction of random, non-adaptive mutations is more meaningfully called devolution than “evolution due to a different set of selection pressures.” It is not due to selection pressures. “Devolution” means that deleterious mutations are accumulating faster than they are selected against.
They are deleterious only as judged by our value system, they are adaptive for the organism. Please note that “adaptive” and even “deleterious” have technical or semi technical meanings as well as the more “common sense” ones.
Artificial lifeforms like the use employed explicitly clarified thank you very much.
Note: Retracted. Seems I was a sloppy reader. See comments below.
No—look, evolution is the fixation of random mutations. Most mutations are not adaptive! The vast majority are either neutral, or destructive, often rendering a protein nonfunctional.
When selective pressure is high, bad mutations are eliminated, and good mutations increase in frequency. When selective pressure is low, bad mutations are introduced much faster than good mutations.
You can’t simultaneously believe in evolution, and not believe in devolution, unless you have a mystical view of evolution as something that magically always adapts.
Huh?
Er, you can if you define devolution the way they do here).
The point is that this is bad terminology—a waste of a perfectly useful term.
The term “devolution” should obviously be being used to refer to this.
I don’t have any real disagreements with the points you make there, but I do think this statement could mislead some:
Loss of complexity can certainly be adaptive too, as I think you acknowledge here:
Also, interesting to note that one cave fish, Astyanax, seems to have lost its eyes not to conserve energy, but because of pleiotropy: the same genes used in eye development are also involved in other traits, like sense of taste, and mutations which produce improvements in taste simultaneously change eye development. It’s hazardous to talk about the fuction of something before you know how it’s made!
Ah I see the source of the misunderstanding. I was fixating on altruism and its adaptive value of lack of there of, in my mind I was challenging characterising the reduction of altruistic behaviour as devolution.
You however where speaking generally of human devolution and even defining the concept for the reader’s benefit!
You are of course right.
If I could sleep I would excuse myself as staying up way to late in this time zone. However I can’t do that. Please accept a delicious slice of cake as apology.
Presumably it’s just the sort of thing GLaDOS says every so often#GLaDOS).
You are kidding me. Did you just say that mutations-reaching-fixation-we-know-they-weren’t-selected-for should be classed as mutations-reaching-fixation-and-adaptive-for-the-organism? That has got to be the dumbest thing… [head explosion].
But low capacity for altruism is selected for in the environment discussed.
Any genetic change due to selection (I doubt nature makes the pretty distinction between natural and artificial selection as clearly as we do) that eliminates an undesired trait or characteristic is basically by definition adaptive and not deleterious (as in harmful, injurious to the organism).
Edit: Why the delete? You’re making Caroline sad.