Re: A FUNDAMENTAL ISSUE
- From: "whitesickle@xxxxxxx" <whitesickle@xxxxxxx>
- Date: Sat, 27 Aug 2005 14:04:37 -0400 (EDT)
Mr. 1g:
You state, "Often comments appear in forums such as sbe, to the effect
that we humans
are this way or that way or another way because our distant ancestors
encountered this or that or the other situation. But if acquired
characteristics are not transmittable, then how would any experience of
our human, and/or pre-human, ancestors have had any impact upon us --
or even
upon their own offspring -- at all."
The theory of acquired characteristic is attributed to Lamarck who
postulated the environment as being the causative change in the
species. The most commonly cited reference is the giraffe who grows a
long neck because it has had over time to reach high in the trees for
leaves. This theory of acquired characteristics has been time and again
scientifically experimentally proven false.
You ask, "But if acquired characteristics are not transmittable, then
how would any experience of our human, and/or pre-human, ancestors have
had any impact upon us -- or even upon their own offspring -- at all."
And, "Does not all the evidence indicate that the source of all
evolutionary
change originates from mutations resulting from "errors of duplication"
in the codes in reproductive organs and their output?"
The main source of evolutionary change is if a species is adaptable to
its environment. In the modern world natural selection has been
somewhat decreased but still functions. To answer your question not all
evolutionary change originates from "errors of duplication" in the
codes in reproductive organs and their output.
I do want to reply to your following question, "But if acquired
characteristics are not transmittable, then how would any experience of
our human, and/or pre-human, ancestors have had any impact upon us --
or even upon their own offspring -- at all."
The answer to that is simple. Despite evolutionary change of the
species over eons there have been some traits selected by natural
selection which have remain encoded in our DNA and which are
"basically" shared with many other creatures. Other primates and
mammals as well as insects. This is not acquired characteristics but
natural selection.
You write, "Granted, those individuals, among any
sexually-reproduction-dependent species. who have not survived -- at
any given time in the history of life on Earth -- have not passed along
their more favorable or more unfavorable codes. But those who
survived, mated, had offspring, and raised those offspring for as long
as necessary for them to, in turn, reproduce... did not pass along any
acquired characteristic. Isn't that right? They merely passed along
"correct" copies of the codings that got passed along to themselves or
they passed along modified copies of the codes that got passed along to
themselves. Isn't that right?" Then you apparently attempt to answer
your own question.
"So, the experiences of the parents who
reproduced would have had no influence upon shaping their young exactly
like themselves or shaping them differently from themselves. Right?
Of course, if the parents (or adoptive parents, or group as a whole)
did not survive to raise the offspring long enough to survive on
his/her own, that "experience" would make a difference. But the
difference still would not pass along anything acquired by the
"rearers," right?"
Wrong. This reminds me of when I suggested modifying aggression through
germline genetic engineering and some posters concerned it would leave
some nations vulnerable to those whose aggression hadn't been modified.
Darwinian evolution in "general" is an extremely long and gradual and
incremental process which doesn't occur in a generation's lifetime or
innumerable generations. The changes are imperceptible. It's only
really been through molecular genetics we've recently been able to draw
some rough but good speculations and conclusions.
In reference to modifying the substrate aggression this would certainly
be intervening in Darwinian evolution but even this would take such a
long time (but nothing compared to Darwinian evolution) that the
concerns posters cited are moot. They would not occur.
The following reminds me of Matt Nuenke on a better day. Eugenics is
very subtly introduced in the following:
"In a nutshell then, why could not progressive offspring, generation
after generation, change in accordance with what situational filters
each
encountered (as individual or as participants in the species at any
given increment of its evolution)? Over time, what difference would it
make if
the ancestors lived in water, crawled on land, flew, or ate one kind of
thing from the food chain or another kind? And, in fact, is this not
exactly why there is so much diversity of life today? Because
offspring were constrained only to be enough like their parents to
avoid being
abandoned too soon, and enough like the parents to be able to live off
what the parents provided by way of food and protection until it (the
individual
offspring) could go its own way and be as different as it could be and
still survive to propagate?"
This definitely has the tinge of Darwinian evolution.The "state" this
author suggests already exists but it seems he would like to intensify
the process. He states, "And, in fact, is this not
exactly why there is so much diversity of life today? Because
offspring were constrained only to be enough like their parents to
avoid being
abandoned too soon, and enough like the parents to be able to live off
what the parents provided by way of food and protection until it (the
individual
offspring) could go its own way and be as different as it could be and
still survive to propagate?"
Regarding the diversity of life today we are currently engaged in the
sixth mass extinction of species on earth. That hardly adds to
diversity. Furthermore, I don't think the human species in general is
that "complex". Genetic "diversity" without "complexity" is an oxymoron
in my opinion. Yeah, everybody has their own unique DNA but how complex
is it?
The author states, ""In a nutshell then, why could not progressive
offspring, generation after generation, change in accordance with what
situational filters each encountered (as individual or as participants
in the species at any given increment of its evolution)?
First of all, although theoretically one could say Darwinian evolution
is going on as we speak for all intent purposes it is not. Again, it
takes in some cases millions of years for Darwinian evolution to effect
noticeable change in an organism. Although not directing stating I
don't believe "situational filters" for "progressive" offspring (what
would you define as progressive?) would be agents for evolutionary
change. I believe the environment has played a signifigant role in
Darwinian evolution but environments change. As I've stated at least a
hundred times on s.b.e. over the years I believe Darwinian evolution
has not adapted to our current environment and threatens the species
with extinction. Regarding germline genetic engineering of humans
obviously the genetically engineered human will be "different" but not
so alien and strange it won't be wanted by "normal" couples.
The author writes, "Over time, what difference would it make if the
ancestors lived in water, crawled on land, flew, or ate one kind of
thing from the food chain or another kind?" All the difference in the
world. Are the similar genetic behaviors of our evolutionary ancestors
as well as current creatures necessarily compatible with civilization
and more importantly our continued survival?
The author anonymous author asks, "In short, what do most of us
believe? Do we believe evolution is a matter of what ancestors
experienced (other than whether they survived to
propagate)? Or do we believe today's creatures are constrained in
their appearance and behavior by what happened to ancestors hundreds of
thousands of years ago... or longer?"
I think the two are interrelated. For example, aggression was necessary
in our evolutionary past due to non-human predators and this was
encoded in our DNA by natural selection. Today, aggression is a deadly
nuisance. For whatever strange reason "nature" allowed us science and
technology and it has continued to grow but this process came about
through means of "exaptation".
Michael Ragland
.
- Follow-Ups:
- Re: A question of timing
- From: Michael Nuwer
- Re: A question of timing
- References:
- A FUNDAMENTAL ISSUE
- From: g
- A FUNDAMENTAL ISSUE
- Prev by Date: Re: Maximum entropy principle
- Next by Date: Re: Is the nucleus the cell's control center?
- Previous by thread: Re: A FUNDAMENTAL ISSUE
- Next by thread: Re: A question of timing
- Index(es):
Relevant Pages
|
