Lamarck - Darwin

[B_spiker067]

Technology Review: A Comeback for Lamarckian Evolution?

"The effects of an animal's environment during adolescence can be passed down to future offspring, according to two new studies. If applicable to humans, the research, done on rodents, suggests that the impact of both childhood education and early abuse could span generations. The findings provide support for a 200-year-old theory of evolution that has been largely dismissed: Lamarckian evolution, which states that acquired characteristics can be passed on to offspring."

Seems to be an epigenome thing. But regardless, if true, speaks to values based outcomes. Cultural values matter.

This is a much more interesting article than the pure conjecture article regarding earth class planets being ubiquitous and comments regarding evident abiogenesis conclusions.

 

[2322]

Not surprising to me. I've been a mild proponent of genetic memory for quite some time.

After all, who loves the sound of bagpipes other than someone with an ancestry where bagpipes are played?

 

[Guy-jin]

I understand that you're more interested in the "cultural values" discourse that could arise from this. However, I don't personally find that particularly interesting, so I'm going down a different path.

I think it's a mis-statement to say to say it's Lamarckian evolution in action over Darwinian evolution. I really take issue with these people saying this makes a case for Lamarckian evolution.

To make that statement, one would have to demonstrate that there is no natural selection occurring to push the epigenetic state towards a particular outcome. This appears to be contrary to their evidence, though: the offspring of poor, abusive mothers end up being poor, abusive mothers themselves. Logically, that would suggest they'd have a lower chance at generating viable offspring, and a reduced chance of their genes (and, in this case, epigenetic state) being passed on for many generations. Meanwhile, the mothers with memory deficits exposed to enriched environment have offspring with increased brain activity, which would likely be selected for positively.

There's no reason to think epigenetic states aren't subject to Darwinian natural selection. To the contrary, based on what we know about cancer, it seems that epigenetic states play a major role in survival and natural selection.

Let's be honest: These people are performing artificial selection. Therefore, to make a case for it being evidence for Lamarckian evolution as opposed to evidence that more than just genes are subject to Darwinian evolution (which is how I see it) seems flimsy at best to me.

 

[Phil Ayesho]

This is actually bullshit.


Epigentic effects are not lamarckian, because what is passed on is NOT an acquired trait.

Rather, environmental pressures can activate or suppress epigenetic effects on gene expression and development. Meaning that, for example, a high stress environment can cause health effects in offspring, even if the high stress environment only occurred during the parent's developmental period.- however, it is not as if the organism acquired a new trait as the result of stress... the stress caused a change that affected development of its offspring, leaving the original organism unaltered.

For example.
Homosexuality may well be such a phenomena... incidence of which seems linked to the number of older male siblings a child has.

The process of gestating male offspring changes the physiology of the mother's womb which has an effect on the development of subsequent male offspring.

However, The mother did not "become homosexual" and THEN pass that acquired trait on to her child... she remained as she was, and her children's development was substantively altered.

Similarly... the idea behind this research is that factors that may seem innocuous or easily overcome for the adult, may well have unforeseen effects on generations of their progeny.


People love to drag lamarck back up.... but his ideas were patently incorrect.
Animals do not acquire traits and then pass them on.

Tho they may have their reproductive biology altered by their environmental circumstances in a manner that results in notable developmental change in their offspring.


It is still a phenomena mediated by DNA.... it just means there is a lot more to so called "junk" DNA than we supposed.

 

[2322]

OK, but what if those poor abusive mothers are skanky sluts with big tits and otherwise hot figures? Men do not give a shit about your mother's abusive tendencies and they're not likely to be topics of discussion down at the neighborhood bar. In fact, I'd argue that women with low self-esteem from abusive environments would be more likely to seek love elsewhere-- like from a child -- rather than a stable mature relationship (which they have not experienced in their parents' lives) and have higher rates of premarital promiscuity. They are, therefore, more likely to reproduce than a more cautious and selective woman.

 

[Guy-jin]

OK, but what if those poor abusive mothers are skanky sluts with big tits and otherwise hot figures? Men do not give a shit about your mother's abusive tendencies and they're not likely to be topics of discussion down at the neighborhood bar. In fact, I'd argue that women with low self-esteem from abusive environments would be more likely to seek love elsewhere-- like from a child -- rather than a stable mature relationship (which they have not experienced in their parents' lives) and have higher rates of premarital promiscuity. They are, therefore, more likely to reproduce than a more cautious and selective woman.

I'm afraid that only goes toward furthering my point that it isn't Lamarckian forces in action, my friend.

In the rat world, if a mother becomes badly behaved enough she'll quite literally ignore her offspring, if not directly kill them, and never pass on her genetic material.

Although the human being in your example may not do that, have we not heard of the dumpster babies teenagers much like the person you're exemplifying create? Do the parents of dumpster babies go on to create a viable family while remaining the types of parents that toss their babies in dumpsters?

That is Darwinian forces in action. Not Lamarckian.

 

[2322]

However, The mother did not "become homosexual" and THEN pass that acquired trait on to her child... she remained as she was, and her children's development was substantively altered.

No, she did not remain as she was. Her body changed to become progressively more resistant to androgens with each successive male pregnancy. I think it's important to note this within your argument.

 

[2322]

I'm afraid that only goes toward furthering my point that it isn't Lamarckian forces in action, my friend.

In the rat world, if a mother becomes badly behaved enough she'll quite literally ignore her offspring, if not directly kill them, and never pass on her genetic material.

Although the human being in your example may not do that, have we not heard of the dumpster babies teenagers much like the person you're exemplifying create? Do the parents of dumpster babies go on to create a viable family while remaining the types of parents that toss their babies in dumpsters?

That is Darwinian forces in action. Not Lamarckian.

The problem there is that we do not live in an environment where dumpster babies necessarily die. We know that at least some are rescued by others and go on to mature and reproduce. Our society intervenes. Same deal with the blind, deaf, severely handicapped or those from severely dysfunctional homes. Outside of societal intervention, these people would most likely fail to reproduce before death.

 

[TurkeyWithaSunburn]

NOVA | Ghost in Your Genes | PBS

If that program is aired in your area you should watch it... it's fascinating.

Could your grandmother surviving a famine impact YOUR likelihood of heart disease, arthritis, and diabetes??

Possibly!

It depends which genes are on and off.

 

[Guy-jin]

The problem there is that we do not live in an environment where dumpster babies necessarily die. We know that at least some are rescued by others and go on to mature and reproduce. Our society intervenes. Same deal with the blind, deaf, severely handicapped or those from severely dysfunctional homes. Outside of societal intervention, these people would most likely fail to reproduce before death.

And yet, that doesn't disqualify it from being Darwinian in nature as opposed to Lamarckian in nature. It actually proves that it's Darwinian and not Lamarckian.

So say dumpster baby gets saved and is raised by a loving family. Said child may have been born with an epigenetic state in her brain that would have made her a bad mother, but the example set forth by her loving family causes a change in epigenetic state that results in part in her being a decent mother herself. She has offspring.

The epigentic state of being a good mother survives.

The epigenetic state that she received from her biological mother is no more.

The "good mother" epigenetic state survived and the "bad mother" epigenetic state didn't.

That is utterly Darwinian.

 

[Phil Ayesho]

No, she did not remain as she was. Her body changed to become progressively more resistant to androgens with each successive male pregnancy. I think it's important to note this within your argument.

That is immaterial.
The changes to her body were the result of her GENETICALLY determined response to exposure to them.

No different than Exercise making my muscles larger... It's my body's genetically determined response to exercise.
Expsoure to allergens, viruses... all manner of things result in systemic changes to your body...
Still Darwinian.

The new thing is that systemic changes to your body can Activate different genes, or modify development in your offspring.

Your offspring is not acquiring a NEW trait... it is manifesting a Latent trait that was there all along.



The mother did not Acquire the trait (homosexuality) that her child was then born with.
Ergo- it was not Lamarckian .

 

[2322]

I'm not arguing for Lamarck at all, I'm just adding my thoughts and opinions as they appear. I'm a big fan of Darwin despite all the hideous experiments he performed on his poor carnivorous plants.