Understanding through Discussion


Welcome! You are not logged in. [ Login ]
EvC Forum active members: 79 (8904 total)
Current session began: 
Page Loaded: 04-18-2019 10:16 AM
27 online now:
Aussie, JonF, vimesey (3 members, 24 visitors)
Chatting now:  Chat room empty
Newest Member: WookieeB
Post Volume:
Total: 849,699 Year: 4,736/19,786 Month: 858/873 Week: 214/376 Day: 7/57 Hour: 0/2


Thread  Details

Email This Thread
Newer Topic | Older Topic
  
1
2Next
Author Topic:   Somewhere between Darwin and Baldwin lies... Lamark?
Ben!
Member (Idle past 1725 days)
Posts: 1154
From: San Diego, 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 responded
 Message 6 by Nuggin, posted 09-18-2005 7:02 PM Ben! has not yet responded

    
AdminJar
Inactive Member


Message 2 of 17 (244496)
09-17-2005 10:26 PM


Thread moved here from the Proposed New Topics forum.
  
RAZD
Member
Posts: 19803
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 10.0


Message 3 of 17 (244650)
09-18-2005 2:43 PM
Reply to: Message 1 by Ben!
09-17-2005 7:05 PM


Baldwin Effect - not much to go on at your link:
http://en.wikipedia.org/wiki/Baldwin_effect

The Baldwin effect is a theory of James Mark Baldwin in which a characteristic, such as individual learning, significantly affects the evolution of the species with respect to that characteristic.

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?

Like the Japanese Macaques
http://www.blueplanetbiomes.org/japanese_macaque.htm

Similarly weight-lifting monkeys (developing extra muscle mass, a typical Lamarkian type feature that is not inherited) increases survival of a band of monkeys that then learn to do weight lifting as part of their "culture"

Similarly human development ...


we are limited in our ability to understand
by our ability to understand

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.


This message is a reply to:
 Message 1 by Ben!, posted 09-17-2005 7:05 PM Ben! has responded

Replies to this message:
 Message 4 by Ben!, posted 09-18-2005 3:13 PM RAZD has responded

  
Ben!
Member (Idle past 1725 days)
Posts: 1154
From: San Diego, 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 responded

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

    
RAZD
Member
Posts: 19803
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 10.0


Message 5 of 17 (244678)
09-18-2005 6:28 PM
Reply to: Message 4 by Ben!
09-18-2005 3:13 PM


Re: Baldwin Effect info
but it's a bit of a read.

Yes it is. The gist that I see though, is not that the features are "lamarkian" but naturally occuring (mutation etc), and that this is more about fixation within the population beyond the period of natural selection operation (the drought has ended, still selecting for camel-backs)... "we started going down this canal and we're going to stay the course"

To me "lamarkian" features are individually aquired characteristics (built up muscles, etc) that are not inheritable (not linked to genes at all, ... well other than having the ability to do it ...)

I do see, however, that purely behavioral changes (such as washing potatoes in salt water to add salt taste) can lead to selection of characteristics that improve ability to do {altered behavior} such as an afinity for water, being able to swim, become the "aquatic ape" ...

This would be "intentional selection" where the species intentionally selects for characteristics that it {desires/values} but that are unrelated specifically to survival or reproduction. A little different from sexual selection. Very Human?

I'm just coming at it from a different perspective.

This message has been edited by RAZD, 09*18*2005 06:29 PM


we are limited in our ability to understand
by our ability to understand

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.


This message is a reply to:
 Message 4 by Ben!, posted 09-18-2005 3:13 PM Ben! has not yet responded

  
Nuggin
Member (Idle past 596 days)
Posts: 2965
From: Los Angeles, CA USA
Joined: 08-09-2005


Message 6 of 17 (244684)
09-18-2005 7:02 PM
Reply to: Message 1 by Ben!
09-17-2005 7:05 PM


Don't think the two are related
My understanding of Lamarkian evolution is that changes that occur to one animal's morphology are passed on to it's offspring. An example: A short necked giraffe stretchs for the tree tops. It's children can stretch further, and the next generation further still.

The experiment which disproves Larmark: Start breeding mice and cut off all their tails. You'd expect to, in short order, be raising new generations of mice which lack tails. Doesn't happen.

It sounds like, from the other posts, that Baldwin is talking more about "instinctual behavior". And here we get into tricky ground. Different species of birds make different shape and size nests. A bird raised away from it's parents will make the nest just the same (so it's not a learned behavior). Does this mean that the "program" for the nest resides in the genes of the bird?

Possibly, but I recall an interesting study about pregnant rats.

Pregnant rats build nests. If you raise a rat with it's mother in a nest, it will later go one to build a nest when it gets pregnant. Likewise, if you take the rat from it's mother and raise it without a nest, when it gets pregnant, it also builds a nest.

Now, here's the kicker. If you take either rat (nest raised and nestless) and keep them in a container with a warm bottom, when they get pregnant they don't build a nest.

Why? Well, when the female rat gets pregnant, her nipples swell and touch the ground. They get cold / irritated and the rat responses by building a nest to solve that problem. Illiminate the irritation, you illiminate the impulse and therefore no nest.

Now is nipple swelling programmed in the genes? Ya. Was it selected for because having a nest better ensures the survivability of the young? No idea.


This message is a reply to:
 Message 1 by Ben!, posted 09-17-2005 7:05 PM Ben! has not yet responded

Replies to this message:
 Message 7 by RAZD, posted 09-19-2005 7:06 AM Nuggin has responded
 Message 10 by NosyNed, posted 09-19-2005 8:17 PM Nuggin has responded

    
RAZD
Member
Posts: 19803
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 10.0


Message 7 of 17 (244810)
09-19-2005 7:06 AM
Reply to: Message 6 by Nuggin
09-18-2005 7:02 PM


Re: Don't think the two are related
or did nipple swelling become part of the genome after nest building because it was not a problem then?

this would be in the baldwin area?

This message has been edited by RAZD, 09*19*2005 07:07 AM


we are limited in our ability to understand
by our ability to understand

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.


This message is a reply to:
 Message 6 by Nuggin, posted 09-18-2005 7:02 PM Nuggin has responded

Replies to this message:
 Message 8 by Nuggin, posted 09-19-2005 10:03 AM RAZD has responded

  
Nuggin
Member (Idle past 596 days)
Posts: 2965
From: Los Angeles, CA USA
Joined: 08-09-2005


Message 8 of 17 (244848)
09-19-2005 10:03 AM
Reply to: Message 7 by RAZD
09-19-2005 7:06 AM


Re: Don't think the two are related
or did nipple swelling become part of the genome after nest building because it was not a problem then?

Well, from my observation, I do believe that all mammals experience nipple swelling during pregnancy. So, I gotta think that pre-dates the rat nest building by quite a bit


This message is a reply to:
 Message 7 by RAZD, posted 09-19-2005 7:06 AM RAZD has responded

Replies to this message:
 Message 9 by RAZD, posted 09-19-2005 8:11 PM Nuggin has responded

    
RAZD
Member
Posts: 19803
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 10.0


Message 9 of 17 (245018)
09-19-2005 8:11 PM
Reply to: Message 8 by Nuggin
09-19-2005 10:03 AM


Re: Don't think the two are related
all mammals experience nipple swelling

Let me rephrase the question:

Did the part of the rat genome that allows {her nipples to swell and touch the ground so they get cold / irritated} become part of the rat genome after {nest building behavior} because it was not a problem then?

ie - not all mammals build nests ergo ...


we are limited in our ability to understand
by our ability to understand

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.


This message is a reply to:
 Message 8 by Nuggin, posted 09-19-2005 10:03 AM Nuggin has responded

Replies to this message:
 Message 12 by Nuggin, posted 09-23-2005 11:44 AM RAZD has responded

  
NosyNed
Member
Posts: 8842
From: Canada
Joined: 04-04-2003
Member Rating: 6.6


Message 10 of 17 (245020)
09-19-2005 8:17 PM
Reply to: Message 6 by Nuggin
09-18-2005 7:02 PM


tailless mice?
The experiment which disproves Larmark: Start breeding mice and cut off all their tails. You'd expect to, in short order, be raising new generations of mice which lack tails. Doesn't happen.

But it could, which might be the Baldwin effect which I don't understand yet.

If some mice suffered infections and died when their tails were cut off but once in awhile a mouse was born tailess and this allowed it to escape the experimenters knife then what might occur?

In other words, if some cultural thing evolved (cleaning rice in the sea) and this conferred a benefit then some mutation which encouraged or supported this behaviour now has an environment in which it may be selected for. The end result would be a cultural change ending up in the genes but through normal darwinian evolution.


This message is a reply to:
 Message 6 by Nuggin, posted 09-18-2005 7:02 PM Nuggin has responded

Replies to this message:
 Message 11 by Omnivorous, posted 09-23-2005 10:23 AM NosyNed has not yet responded
 Message 13 by Nuggin, posted 09-23-2005 11:47 AM NosyNed has not yet responded

  
Omnivorous
Member (Idle past 1071 days)
Posts: 3808
From: Adirondackia
Joined: 07-21-2005


Message 11 of 17 (245917)
09-23-2005 10:23 AM
Reply to: Message 10 by NosyNed
09-19-2005 8:17 PM


Re: tailless mice?
NosyNed writes:

If some mice suffered infections and died when their tails were cut off but once in awhile a mouse was born tailess and this allowed it to escape the experimenters knife then what might occur?

In other words, if some cultural thing evolved (cleaning rice in the sea) and this conferred a benefit then some mutation which encouraged or supported this behaviour now has an environment in which it may be selected for. The end result would be a cultural change ending up in the genes but through normal darwinian evolution.

And if sexual selection kicked in (avoiding scarred/infected/post-infection partners), it could happen quickly.

Edited to correct haywire quote.

This message has been edited by Omnivorous, 09-23-2005 11:42 AM


This message is a reply to:
 Message 10 by NosyNed, posted 09-19-2005 8:17 PM NosyNed has not yet responded

    
Nuggin
Member (Idle past 596 days)
Posts: 2965
From: Los Angeles, CA USA
Joined: 08-09-2005


Message 12 of 17 (245954)
09-23-2005 11:44 AM
Reply to: Message 9 by RAZD
09-19-2005 8:11 PM


Re: Don't think the two are related
not all mammals build nests ergo

Well, not all mammals have nipples that drag on the ground. :)

Honestly, I couldn't tell you where and when rats started building nests. I'd be surprised if anyone could.

My larger point was that a change in a gene can have a physical effect which in turn causes a particular behavior. That doesn't mean that the behavior is in and of itself genetically programmed.


This message is a reply to:
 Message 9 by RAZD, posted 09-19-2005 8:11 PM RAZD has responded

Replies to this message:
 Message 14 by RAZD, posted 09-23-2005 7:46 PM Nuggin has not yet responded

    
Nuggin
Member (Idle past 596 days)
Posts: 2965
From: Los Angeles, CA USA
Joined: 08-09-2005


Message 13 of 17 (245955)
09-23-2005 11:47 AM
Reply to: Message 10 by NosyNed
09-19-2005 8:17 PM


Re: tailless mice?
The end result would be a cultural change ending up in the genes but through normal darwinian evolution.

Maybe in the rice scenario, but not in the mouse one. The odds of a given mouse being born tailless should be universal. The odds of that mouse being part of the study in which we cut off mice tails, pretty astronomical. But, even if the mouse was born into that study, it wouldn't have been because of the abuse visited on the previous generations.


This message is a reply to:
 Message 10 by NosyNed, posted 09-19-2005 8:17 PM NosyNed has not yet responded

Replies to this message:
 Message 15 by Omnivorous, posted 09-29-2005 11:09 AM Nuggin has responded

    
RAZD
Member
Posts: 19803
From: the other end of the sidewalk
Joined: 03-14-2004
Member Rating: 10.0


Message 14 of 17 (246025)
09-23-2005 7:46 PM
Reply to: Message 12 by Nuggin
09-23-2005 11:44 AM


Re: Don't think the two are related
Right, and my point was that once a certain behavior became ingrown in a species that genetic drift could occur to change a feature that wouldn't have without the behavioral change, perhaps it allowed rat legs to get shorter to make getting into holes for food easier.


we are limited in our ability to understand
by our ability to understand

RebelAAmerican.Zen[Deist
... to learn ... to think ... to live ... to laugh ...
to share.


This message is a reply to:
 Message 12 by Nuggin, posted 09-23-2005 11:44 AM Nuggin has not yet responded

  
Omnivorous
Member (Idle past 1071 days)
Posts: 3808
From: Adirondackia
Joined: 07-21-2005


Message 15 of 17 (247268)
09-29-2005 11:09 AM
Reply to: Message 13 by Nuggin
09-23-2005 11:47 AM


selection is as selection does
Nuggin writes:

But, even if the mouse was born into that study, it wouldn't have been because of the abuse visited on the previous generations.

Hi, Nuggin. I'm not sure I understand your objection.

Your statement quoted above is clearly true, but the ongoing "abuse" would still be a selective pressure, and the probability of the "non-tail" mutation is not germane--given enough time, whatever can happen, will.

Perhaps the Heike crab is a good example, where for centuries Japanese fishermen have released crabs whose shell markings are thought to resemble a samurai's face. Both the number of such crabs and their likeness to samurai faces have increased; the resemblance-bearing individual crab has increased chances of survival (and reproduction), and, it seems to me, so does the species, since there is now a large subpopulation we will not so readily hunt into extinction.


This message is a reply to:
 Message 13 by Nuggin, posted 09-23-2005 11:47 AM Nuggin has responded

Replies to this message:
 Message 16 by Nuggin, posted 09-29-2005 11:25 AM Omnivorous has responded

    
1
2Next
Newer Topic | Older Topic
Jump to:


Copyright 2001-2018 by EvC Forum, All Rights Reserved

™ Version 4.0 Beta
Innovative software from Qwixotic © 2019