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Author Topic:   Somewhere between Darwin and Baldwin lies... Lamark?
Ben!
Member (Idle past 1399 days)
Posts: 1161
From: Hayward, CA
Joined: 10-14-2004


Message 1 of 17 (244445)
09-17-2005 7:05 PM


Let's see if I can get this right (please correct me where I'm wrong in my summaries)...
Everywhere I've read about Lamarckism, I read that it's been "discredited" or "isn't true." In trying to understand the biological bases for "innate behavior" and the steps a species goes through to aquire them, I'm not quite convinced.
Current theory on trait expression and aquisition are described by Mendelian inheritance and neodarwinism. Traits are propogated from generation to generation via Mendelian rules of inheritance. New traits are acquired by a population via mutation (changes to the traits in an individual) and natural selection (interaction of the trait with the environment, leading to propogation of the trait through the population ).
Part of this idea of inheritance and aquisition of new traits via random mutation and natural selection includes the Baldwin effect. In the Baldwin Effect, traits which are NOT expressed in "normal" development, but only expressed in development within "abnormal" environments, if selected for, can begin to express themselves within the course of normal development.
My question is, is the Baldwin effect really just Lamarkism in the case of selection pressure? I'll try and walk a bit through the steps. Can't basically all acquired characteristics be understood as simply characteristics developed in a "abnormal" environment? And can't aquisition be considered as "characteristics appearing in the standard developmental environment which previously did not"? If this is the case, then the only difference I see between Lamarkism and the Baldwin effect is selection pressure.
Thus, would it be accurate to say that the Baldwin effect shows Lamarkian inheritance in the case where there's selection pressure?
(Biological Evolution please)

Replies to this message:
 Message 3 by RAZD, posted 09-18-2005 2:43 PM Ben! has replied
 Message 6 by Nuggin, posted 09-18-2005 7:02 PM Ben! has not replied

  
Ben!
Member (Idle past 1399 days)
Posts: 1161
From: Hayward, CA
Joined: 10-14-2004


Message 4 of 17 (244656)
09-18-2005 3:13 PM
Reply to: Message 3 by RAZD
09-18-2005 2:43 PM


Baldwin Effect info
Hi RAZD,
You're right, it's a really bad link... Brad (and others) gave good information about the Baldwin effect here, but it's a bit of a read. A lot of the basic information is a paper "Genetic Assimilation of an Acquired Character" by Waddington (thanks to Brad).
In other words {learned\invented} behavior that is communicated within a population can increase the survival ability of that population with no change at the biological level?
I think the idea is that the trait is "assimilated" over time into the genome through selection pressure. The trait (behavioral or morphological) originally is not expressed in the "normal" developmental environment, but over time, through this "assimilation", it comes to be.
Like the Japanese Macaques
I would say it would be like... like if some Japanese Macaques learned to make snowballs, taught others... and that at some point, if you rasied a Macaque in a Macaque community that did NOT know how to make snowballs, it would "innately know" how to do it. The "original" environment is a community with no knowledge of snowballs, so you'd have to have genetic assimilation which would give rise to the behavior without learning, but rather springing forth innately.
Did my best to work with your example, but my analysis may be flawed. The main point is that what is "acquired" through the environment is "assimilated" to the genome, such that it becomes more "robust" (Waddington's "canalization") and begins to appear AS PART OF DEVELOPMENT in more diverse environments, including the original environment where it was "acquired" in the first place.
The classic example, from the Waddington paper, is that of cross-veined-ness in fruitflies. I don't think I can summarize it well (a flaw in my knowledge) at the moment, so I hope you can find time to take a look at the paper. I'll try and take a look at it sometime today as well.
And sorry for the poor link for the Baldwin effect. Hope what I've written helps clarify it.
Thanks!
Ben
AbE: Fixed link and added subtitle.
This message has been edited by Ben, Sunday, 2005/09/18 12:13 PM

This message is a reply to:
 Message 3 by RAZD, posted 09-18-2005 2:43 PM RAZD has replied

Replies to this message:
 Message 5 by RAZD, posted 09-18-2005 6:28 PM Ben! has not replied

  
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