MemberlistThe Library Index  FAQFAQ   SearchSearch   RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
Epigenetics - Lamarckism? (Life Sciences)
Reply to topic Goto page 1, 2, 3  Next
View previous topic :: View next topic  
EndlesslyRocking



View user's profile
Reply with quote

Has anyone heard of epigenetics? I hadn't heard of it until today.

"In biology, the term epigenetics refers to changes in gene expression that are stable between cell divisions, and sometimes between generations, but do not involve changes in the underlying DNA sequence of the organism. Basically, it is a term used to describe the idea that environmental factors can cause an organism's genes to behave (or "express themselves") differently, even though the genes themselves don't change."

http://en.wikipedia.org/wiki/Epigenetics

Could epigenetics be interpreted as a kind of Lamarckism?
Send private message
Mick Harper
Site Admin

In: London
View user's profile
Reply with quote

I may be jumping the gun but Applied Epistemology endorses Lamarkism on the grounds
a) the evidence for evolution is overwhelming
b) the evidence against neo-Darwinism is overwhelming.
Send private message
DPCrisp


In: Bedfordshire
View user's profile
Reply with quote

a) the evidence for evolution is overwhelming

I'm not aware of any evidence for evolution. My nephew's biology text book's Contents promised to give us the argument: I dived in... and found nothing beyond "it looks like it".

Facts are theory-laden.
Send private message
Mick Harper
Site Admin

In: London
View user's profile
Reply with quote

Sorry, a small mis-statement (but no doubt a significant one). What I meant was that the evidence that species have altered over time is overwhelming. To that extent I think it would be true to say that species have 'evolved' over time (removing any notion of advancement from that term).
Send private message
DPCrisp


In: Bedfordshire
View user's profile
Reply with quote

Sorry, a small mis-statement (but no doubt a significant one).

Yes and no. It's a matter of correctly representing, to ourselves as much as to anyone else, what it is we are actually doing.

What I meant was that the evidence that species have altered over time is overwhelming.

Even if you mean "the selection of species present in the world has changed over time", as opposed to "those species changed into these species", {We can say pudding replaces dinner on the table in front of us without saying anything about whether or how one evolves into the other.} there is still no evidence in the conventional sense.

It's not that evolution is deduced from any evidence, as in any forensic case; it's that certain facts are deduced to be evidence from the premise that there is evolution.

Theoretic circularity.
Send private message
Mick Harper
Site Admin

In: London
View user's profile
Reply with quote

Yes, I thought carefully about the pudding-replacing-dinner model and decided that the evidence is overwhelming that that (at least) doesn't happen. One lot of animals are not regularly swept away by some dumb waiter to be be replaced with another lot that bears scant resemblance. As the song says, evolution rather than revolution. We should be able to reclaim the word without too much baggage.
Send private message
Ishmael


In: Toronto
View user's profile
Reply with quote

Mick Harper wrote:
I may be jumping the gun but Applied Epistemology endorses Lamarkism on the grounds
a) the evidence for evolution is overwhelming
b) the evidence against neo-Darwinism is overwhelming
.

Look. Both Darwinism and Lamarckism are based on this premise: Life evolves to fit the environment.

What if, instead, life is the mechanism by which the environment is altered??? Life then must be as it must be in order to effect the intended changes upon the planet.

Just think about it Mick. Everywhere you look, it's the planet that is shaped by life -- not the other way around.
Send private message
Komorikid


In: Gold Coast, Australia
View user's profile
Reply with quote

This is my post from another thread but it also seems to fit here.

Lamarckism has never gone away. It is still the core belief of many biologists despite the current paradigm's religious belief in neo-Darwinism. Darwin himself shared many of Lamarck's view but this is never mention in the hallowed halls of academia. In two recent experiments conducted by biologists Lamarckian principles have been verified.

The first example was bacteria samples that could not survive in a lactose environment. The test bacterium modified a gene that allowed it to thrive in the lactose solution and passed it on to its 'children' who were fully able to propergate in the 'alien' environment. In the word of Cairns who conducted the experiment 'the bacteria possessed the ability to generate precisely the mutations needed to adapt to the new environment'

The second was more interesting. In order to survive in a hostile environment (this time not saline) a different bacteria excised one gene then modified another in response to the new environment. The gene that was modified could not be changed without first getting rid of another prior to the modification.
According to Barry Hall 'we now have to examine the notion implied by the results that mutation, like other biological processes, is subject to regulation by environmental factors.'

The experiments proved that the environment determined the mutation a core belief of Lamarckism.
Send private message
EndlesslyRocking



View user's profile
Reply with quote

Ishmael wrote:
Mick Harper wrote:
I may be jumping the gun but Applied Epistemology endorses Lamarkism on the grounds
a) the evidence for evolution is overwhelming
b) the evidence against neo-Darwinism is overwhelming
.

Look. Both Darwinism and Lamarckism are based on this premise: Life evolves to fit the environment.


We all agree that life changes form. But why must the reasons for changing be teleological? I previously thought that Darwinism was goal oriented and Lamarckism was not, but I now realize that was wrong.

But, why can't the changes be random things that just happened. Maybe some changes work better than others, but when the changes occurred there was no goal to adapt.

There's a difference between claiming:

a) Life forms change, and sometimes those changes happen to be beneficial.
versus
b) Life forms change in order to fit the environment.
Send private message
DPCrisp


In: Bedfordshire
View user's profile
Reply with quote

Yes, I thought carefully about the pudding-replacing-dinner model and decided that the evidence is overwhelming that that (at least) doesn't happen. One lot of animals are not regularly swept away by some dumb waiter to be replaced with another lot that bears scant resemblance.

No, you've done the same thing again. The new lot could bear an uncanny resemblance to the previous lot, but the point is that we are working from the model and saying "look: this fits, it's evidence for the model". And people with a different model make the same claim for the fit with theirs.

You can look at the percentile charts of children's weights two ways: as a bunch of trends as kids age and grow; or as a snapshot of a lot of kids covering all ages and weights. That's two models for 'slicing' the data: and one does not preclude the other. (An overarching model says whether the two views are in fact equivalent; whether data obtained one way can be used in the other.)

There is no evidence in the forensic sense of suggesting one scenario and excluding others. Evolution is the paradigm that we do not question: something has to serve as the foundation upon which other work is carried out.

On the Time Team forum, I kept asking for the evidence that makes the case for Iron Age settlement patterns or roads & towns being of Roman foundation: they couldn't answer and they couldn't admit that the evidence also fits the THOBR model. They (re)act as though fitting their model proves it and thereby excludes yours. (I said this out loud and no one took any notice.)

We, at least, should admit that there is no evidence for or against evolution. The fact of evolution is not what we are trying to prove but its manner.

If you say

"I thought carefully about the pudding-replacing-dinner model and decided that that doesn't happen. One lot of animals are not regularly swept away by some dumb waiter to be replaced with another lot."

I will not argue.

You know all this well enough, but the baboon can not see his own red bottom.
Send private message
DPCrisp


In: Bedfordshire
View user's profile
Reply with quote

Just think about it Mick. Everywhere you look, it's the planet that is shaped by life -- not the other way around.

"Not the other way around" or "and the other way around"?
Send private message
DPCrisp


In: Bedfordshire
View user's profile
Reply with quote

Lamarckism has never gone away. It is still the core belief of many biologists

Yesterday, telly said experiments with rats shows that the children prefer the type of food their mothers were eating, either rat pellets or junk food.

'the bacteria possessed the ability to generate precisely the mutations needed to adapt to the new environment'

'we now have to examine the notion implied by the results that mutation, like other biological processes, is subject to regulation by environmental factors.'

The trouble here is to determine whether these mutations occurred or occurred because.

In what sense were they intolerant before if as soon they were exposed they produced these necessary mutations? Isn't that a technique it had at its disposal, like 'shutting itself down' in the absence of food?

Assuming the intolerance is shown by the vast majority being killed, isn't it rather easy to find the one that says "ah, just right" out of the millions that may or may not have been trying things?

And how do the statistics, in terms of sheer numbers and viable genetic permutations, translate to complex organisms? "Bacteria can adapt rather easily to any and every environment on Earth" is a far cry from "organisms sort out their own evolution".

Death is just as important as life, so failure to adapt (quickly) has got to be a pretty universal principle.

---

The "system" has to be instantiated at the individual level, so on that basis: bacteria eat one another by creating a locally toxic environment, right? So switching from intolerant to tolerant is like saying "hah! you can't eat me" when a lactose-secreting bug comes along. "The environment" (for organisms and for their subsystems)can be thought of as very local and very fleeting.
Send private message
Ishmael


In: Toronto
View user's profile
Reply with quote

EndlesslyRocking wrote:
We all agree that life changes form. But why must the reasons for changing be teleological? I previously thought that Darwinism was goal oriented and Lamarckism was not, but I now realize that was wrong.

Neither is goal-oriented. This is seen as a strength.

However, it is my believe that positing purpose can be a productive investigative methodology for understanding the workings of the natural world. We will see if my methods produce valid results.

There's a difference between claiming:
a) Life forms change, and sometimes those changes happen to be beneficial.versus
b) Life forms change in order to fit the environment
.

I can't see a difference. Can you see a difference?
Send private message
Ishmael


In: Toronto
View user's profile
Reply with quote

DPCrisp wrote:
On the Time Team forum, I kept asking for the evidence that makes the case for Iron Age settlement patterns or roads & towns being of Roman foundation: they couldn't answer and they couldn't admit that the evidence also fits the THOBR model. They (re)act as though fitting their model proves it and thereby excludes yours. (I said this out loud and no one took any notice.)

But there is a way of judging between models. The simplest wins. This is the advantage Darwin has over Lamark. Darwin requires no thinking mechanism to guide changes.

This advantage holds only so long as the simpler model fits the data.
Send private message
DPCrisp


In: Bedfordshire
View user's profile
Reply with quote

But there is a way of judging between models.

Certainly, but this a model of models. You even need a model of likelihood, simplicity, judgement... in order to judge the models.

The likelihood of an accident happening, say, is a very different thing from the likelihood that God exists -- a difference in kind, not in degree. How do you answer someone who says Creationism is the simplest model?

The simplest wins.

Yes, this is telling: "wins" points to the fact that it's a game people play rather than some fabric of the universe. How do you answer someone who rejects Occam's Razor?

Darwin requires no thinking mechanism to guide changes.

I didn't think Lamarck does either.

This advantage holds only so long as the simpler model fits the data.

Yes, we know the rules and we are playing along, but let's not pretend we have to.

Applied Epistemology explicitly seeks to penetrate the edifice and find whether the foundations really are agreed principles. We can argue that academics contradict their own principles or that one principle is overridden by something more fundamental, but unless we are on common ground, our arguments make no impact. Common ground runs out and we would do well to know where: the self-evidently-true is our bread-and-butter.

We can only delve into evolution where evolution is assumed. If someone else doesn't believe the phenomenon even exists, we have nothing to say to each other.
Send private message
Display posts from previous:   
Reply to topic Goto page 1, 2, 3  Next

Jump to:  
Page 1 of 3

MemberlistThe Library Index  FAQFAQ   SearchSearch   RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 


Powered by phpBB © 2001, 2005 phpBB Group