Do you think any aliens exist in the universe?

[Swammerdami]

@pood suggested in post 904 that evolution might work differently on other planets. In post 907, they suggested it might be more like Lamarckianism.

Could it be the case? Technically, yes, the chance is not zero. But is it likely? I doubt it. Our own experience with evolution is that Lamarckianism plays a very small role at most in evolution. If it is to play a larger role in evolution on other planets, then it raises several questions:

1. What differences would there need to be in life forms in order for Lamarckianism to play a greater role?

Though banned, mankind already has the capability of germline editing ("improving" the DNA of ova or sperm). Could a species which used such technology be said to be evolving via Lamarckianism? (Or am I misusing the word "Lamarckianism"?) One can imagine a society which has used such techniques for many thousands of years and thereby evolved creatures completely different from their pre-edited ancestors.

I suppose this scenario doesn't count if it takes millions of years of Darwinian evolution to evolve creatures with the talent for such DNA editing.

 

[Kylie]

@pood suggested in post 904 that evolution might work differently on other planets. In post 907, they suggested it might be more like Lamarckianism.

Could it be the case? Technically, yes, the chance is not zero. But is it likely? I doubt it. Our own experience with evolution is that Lamarckianism plays a very small role at most in evolution. If it is to play a larger role in evolution on other planets, then it raises several questions:

1. What differences would there need to be in life forms in order for Lamarckianism to play a greater role?

Though banned, mankind already has the capability of germline editing ("improving" the DNA of ova or sperm). Could a species which used such technology be said to be evolving via Lamarckianism? (Or am I misusing the word "Lamarckianism"?) One can imagine a society which has used such techniques for many thousands of years and thereby evolved creatures completely different from their pre-edited ancestors.

I suppose this scenario doesn't count if it takes millions of years of Darwinian evolution to evolve creatures with the talent for such DNA editing.

I wouldn't call that Lamarckianism.

My understanding of Lamarckianism is that it happens without any artificial involvement. For example, if an animal has to stretch its neck up to reach some leaves to eat, then that changes the genes in is germ cells (sperm or ova) so that any offspring will have a longer neck.

Such artificial meddling doesn't seem to fit that definition, not to me at least.

 

[Swammerdami]

Rant: Here is an article by a science writer (Cooper) to remind us that many science writers don't know science. I put it here, rather than in the Rants thread, because it links to an actual science article (by Hirakawa et al) that suggests RNA may develop more easily on alien worlds than previously thought.

Two things lead me to the conclusion that the first article linked above is deficient.

(1) Cooper writes: "if ions are atoms or molecules that have a positive electrical charge, then anions have an overall negative electrical charge."
"Cations" is the word he was looking for. Ions covers both cations and anions.

(2) The article's title is misleading: "How did life begin on Earth? New experiments support 'RNA world' hypothesis"
That RNA arose before DNA (Cooper's meaning) is NOT controversial. But "RNA World" is the hypothesis that the earliest proto-life used RNA with little or no proteins. (The alternate hypothesis is that RNA and protein co-evolved.) I verified that Hirakawa's paper doesn't have any instances of the word "world."

 

[Loren Pechtel]

Though banned, mankind already has the capability of germline editing ("improving" the DNA of ova or sperm). Could a species which used such technology be said to be evolving via Lamarckianism? (Or am I misusing the word "Lamarckianism"?) One can imagine a society which has used such techniques for many thousands of years and thereby evolved creatures completely different from their pre-edited ancestors.

I suppose this scenario doesn't count if it takes millions of years of Darwinian evolution to evolve creatures with the talent for such DNA editing.

That's not Lamarkian.

Lamarkian is where you put a man and a woman through extreme strength training and then have them make a baby that will be stronger because of what the parents did. As opposed to Darwinian evolution where you put everyone through the strength training and then select the strongest man and the strongest woman to have a stronger baby.

Gene editing (quite legitimately banned at present because current techniques are not reliable enough) will (if we live long enough, something I don't expect at this point) create a whole different approach to evolution, but it won't be either Darwinian nor Lamarkian.

 

[Loren Pechtel]

@pood suggested in post 904 that evolution might work differently on other planets. In post 907, they suggested it might be more like Lamarckianism.

Could it be the case? Technically, yes, the chance is not zero. But is it likely? I doubt it. Our own experience with evolution is that Lamarckianism plays a very small role at most in evolution. If it is to play a larger role in evolution on other planets, then it raises several questions:

1. What differences would there need to be in life forms in order for Lamarckianism to play a greater role?

Though banned, mankind already has the capability of germline editing ("improving" the DNA of ova or sperm). Could a species which used such technology be said to be evolving via Lamarckianism? (Or am I misusing the word "Lamarckianism"?) One can imagine a society which has used such techniques for many thousands of years and thereby evolved creatures completely different from their pre-edited ancestors.

I suppose this scenario doesn't count if it takes millions of years of Darwinian evolution to evolve creatures with the talent for such DNA editing.

I wouldn't call that Lamarckianism.

My understanding of Lamarckianism is that it happens without any artificial involvement. For example, if an animal has to stretch its neck up to reach some leaves to eat, then that changes the genes in is germ cells (sperm or ova) so that any offspring will have a longer neck.

Such artificial meddling doesn't seem to fit that definition, not to me at least.

Doesn't matter if it has to stretch to get leaves or because of a program of stretching. It still doesn't happen because the baby is based off the genetic codes, not the expression of the genetic codes.

 

[bilby]

As an aside, it seems that Giraffes having long necks is not helpful at all for feeding purposes, and that their necks are a runaway feedback sexual selection feature, like stag's antlers. Like stags, male giraffes use their absurdly impractical feature both to impress mates, and to fight rivals.

The entire giraffe neck analogy is based on an incorrect assumption that the long neck has a direct benefit in obtaining sustenance, but it's really just to impress the ladies.

It's as though a bunch of anthropologists decided that Ferrari ownership led to reproductive success, because a man with a Ferrari can get to the supermarket quicker than his rivals, and thereby gains an advantage in obtaining food.

So much for 'just-so' stories in evolutionary biology.

 

[DBT]

Our brains create a subjective, mental simulation of the external world, which is our experience of it.

 

[Kylie]

As an aside, it seems that Giraffes having long necks is not helpful at all for feeding purposes, and that their necks are a runaway feedback sexual selection feature, like stag's antlers. Like stags, male giraffes use their absurdly impractical feature both to impress mates, and to fight rivals.

Do you have a source to show that it's primarily sexual selection?

Because they sure do seem to provide a feeding advantage...

 

[bilby]

As an aside, it seems that Giraffes having long necks is not helpful at all for feeding purposes, and that their necks are a runaway feedback sexual selection feature, like stag's antlers. Like stags, male giraffes use their absurdly impractical feature both to impress mates, and to fight rivals.

Do you have a source to show that it's primarily sexual selection?

Because they sure do seem to provide a feeding advantage...

https://www.journals.uchicago.edu/doi/abs/10.1086/285955

Winning by a neck: sexual selection in the evolution of giraffe​

Robert E Simmons, Lue Scheepers
The American Naturalist 148 (5), 771-786, 1996
A classic example of extreme morphological adaptation to the environment is the neck of the giraffe (Giraffa camelopardalis), a trait that most biologists since Darwin have attributed to competition with other mammalian browsers. However, in searching for present-day evidence for the maintenance of the long neck, we find that during the dry season (when feeding competition should be most intense) giraffe generally feed from low shrubs, not tall trees; females spend over 50% of their time feeding with their necks horizontal; both sexes feed faster and most often with their necks bent; and other sympatric browsers show little foraging height partitioning. Each result suggests that long necks did not evolve specifically for feeding at higher levels. Isometric scaling of neck-to-leg ratios from the okapi Okapia johnstoni indicates that giraffe neck length has increased proportionately more than leg length-an unexpected and physiologically costly method of gaining height. We thus find little critical support for the Darwinian feeding competition idea. We suggest a novel alternative: increased neck length has a sexually selected origin. Males fight for dominance and access to females in a unique way: by clubbing opponents with well-armored heads on long necks. Injury and death during intrasexual combat is not uncommon, and larger-necked males are dominant and gain the greatest access to estrous females. Males' necks and skulls are not only larger and more armored than those of females' (which do not fight), but they also continue growing with age. Larger males also exhibit positive allometry, a prediction of sexually selected characters, investing relatively more in massive necks than smaller males. Despite being larger, males also incur higher predation costs than females. We conclude that sexual selection has been overlooked as a possible explanation for the giraffe's long neck, and on present evidence it provides a better explanation than one of natural selection via feeding competition.

 

[Kylie]

As an aside, it seems that Giraffes having long necks is not helpful at all for feeding purposes, and that their necks are a runaway feedback sexual selection feature, like stag's antlers. Like stags, male giraffes use their absurdly impractical feature both to impress mates, and to fight rivals.

Do you have a source to show that it's primarily sexual selection?

Because they sure do seem to provide a feeding advantage...

https://www.journals.uchicago.edu/doi/abs/10.1086/285955

Winning by a neck: sexual selection in the evolution of giraffe​

Robert E Simmons, Lue Scheepers
The American Naturalist 148 (5), 771-786, 1996
A classic example of extreme morphological adaptation to the environment is the neck of the giraffe (Giraffa camelopardalis), a trait that most biologists since Darwin have attributed to competition with other mammalian browsers. However, in searching for present-day evidence for the maintenance of the long neck, we find that during the dry season (when feeding competition should be most intense) giraffe generally feed from low shrubs, not tall trees; females spend over 50% of their time feeding with their necks horizontal; both sexes feed faster and most often with their necks bent; and other sympatric browsers show little foraging height partitioning. Each result suggests that long necks did not evolve specifically for feeding at higher levels. Isometric scaling of neck-to-leg ratios from the okapi Okapia johnstoni indicates that giraffe neck length has increased proportionately more than leg length-an unexpected and physiologically costly method of gaining height. We thus find little critical support for the Darwinian feeding competition idea. We suggest a novel alternative: increased neck length has a sexually selected origin. Males fight for dominance and access to females in a unique way: by clubbing opponents with well-armored heads on long necks. Injury and death during intrasexual combat is not uncommon, and larger-necked males are dominant and gain the greatest access to estrous females. Males' necks and skulls are not only larger and more armored than those of females' (which do not fight), but they also continue growing with age. Larger males also exhibit positive allometry, a prediction of sexually selected characters, investing relatively more in massive necks than smaller males. Despite being larger, males also incur higher predation costs than females. We conclude that sexual selection has been overlooked as a possible explanation for the giraffe's long neck, and on present evidence it provides a better explanation than one of natural selection via feeding competition.

Interesting, thanks for that.

 

[Don2 (Don1 Revised)]

I pretty much agree with all of this, especially the infeasibility of long-distance space travel. My point was just to remain somewhat agnostic on how swiftly complex life could evolve on another planet. It took billions of years to evolve here, but it is only one data point, and you can’t really generalize from one example. Maybe other planets are better suited to life, and complex life, than our own.

How would this work? Planets are not better suited for life, life becomes better suited to the planets. That's how evolution works.

Then, too — and this is entirely speculative — maybe evolution as we understand it does not hold on other planets, and that organisms can develop in different and faster ways? Not long ago I posted about a scientific study suggesting that not all mutations are random with respect to environment, and may in fact occur in response to a changed environment. I have not seen any commentary on this study elsewhere online or in print, but if the study is true it suggests we may have some revisions to do in evolutionary theory.

Why would the principles of evolution not work on other planets the same way they work here?

Random mutations produce a variety of different traits. Those traits that increase the likelihood of reproduction are going to get passed down to offsrping. Those traits that decrease the likelihood of reproduction are going to die out.

Why would that be any different on other planets?

Also, if we're going to suggest that somehow the rate of evolution is different on different planets, then it's just as likely that Earth is the planet that has the fastest rate of evolution.

Sure, I agree with all this, but — we have one data point. Earth. We really don’t know if the principles of evolution would work the same on other planets. As noted, I posted a science article recently that questions whether even here on earth, all mutations are random with respect to the environment. I can envision a set of circumstances in which, say, Lamarckism holds, or something we have never considered.

Why would natural selection stop working as an evolutionary mechanism?

How could Lamarckian evolution work?

https://www.sciencedirect.com/science/article/pii/S0079610719301129

 

[Kylie]

I pretty much agree with all of this, especially the infeasibility of long-distance space travel. My point was just to remain somewhat agnostic on how swiftly complex life could evolve on another planet. It took billions of years to evolve here, but it is only one data point, and you can’t really generalize from one example. Maybe other planets are better suited to life, and complex life, than our own.

How would this work? Planets are not better suited for life, life becomes better suited to the planets. That's how evolution works.

Then, too — and this is entirely speculative — maybe evolution as we understand it does not hold on other planets, and that organisms can develop in different and faster ways? Not long ago I posted about a scientific study suggesting that not all mutations are random with respect to environment, and may in fact occur in response to a changed environment. I have not seen any commentary on this study elsewhere online or in print, but if the study is true it suggests we may have some revisions to do in evolutionary theory.

Why would the principles of evolution not work on other planets the same way they work here?

Random mutations produce a variety of different traits. Those traits that increase the likelihood of reproduction are going to get passed down to offsrping. Those traits that decrease the likelihood of reproduction are going to die out.

Why would that be any different on other planets?

Also, if we're going to suggest that somehow the rate of evolution is different on different planets, then it's just as likely that Earth is the planet that has the fastest rate of evolution.

Sure, I agree with all this, but — we have one data point. Earth. We really don’t know if the principles of evolution would work the same on other planets. As noted, I posted a science article recently that questions whether even here on earth, all mutations are random with respect to the environment. I can envision a set of circumstances in which, say, Lamarckism holds, or something we have never considered.

Why would natural selection stop working as an evolutionary mechanism?

How could Lamarckian evolution work?

https://www.sciencedirect.com/science/article/pii/S0079610719301129

That paper is speculation. There is no confirmed evidence for a mechanism for this to actually occur. They suggest horizontal gene transfer could explain it, but that happens in microbes, and its relevance to Lamarckian evolution is speculative. The paper also assumes that genetic material can survive travelling through space, yet exposure to extreme amounts of radiation as well as the incredibly long times spans involved are significant barriers which the paper does not explain.

 

[Don2 (Don1 Revised)]

I pretty much agree with all of this, especially the infeasibility of long-distance space travel. My point was just to remain somewhat agnostic on how swiftly complex life could evolve on another planet. It took billions of years to evolve here, but it is only one data point, and you can’t really generalize from one example. Maybe other planets are better suited to life, and complex life, than our own.

How would this work? Planets are not better suited for life, life becomes better suited to the planets. That's how evolution works.

Then, too — and this is entirely speculative — maybe evolution as we understand it does not hold on other planets, and that organisms can develop in different and faster ways? Not long ago I posted about a scientific study suggesting that not all mutations are random with respect to environment, and may in fact occur in response to a changed environment. I have not seen any commentary on this study elsewhere online or in print, but if the study is true it suggests we may have some revisions to do in evolutionary theory.

Why would the principles of evolution not work on other planets the same way they work here?

Random mutations produce a variety of different traits. Those traits that increase the likelihood of reproduction are going to get passed down to offsrping. Those traits that decrease the likelihood of reproduction are going to die out.

Why would that be any different on other planets?

Also, if we're going to suggest that somehow the rate of evolution is different on different planets, then it's just as likely that Earth is the planet that has the fastest rate of evolution.

Sure, I agree with all this, but — we have one data point. Earth. We really don’t know if the principles of evolution would work the same on other planets. As noted, I posted a science article recently that questions whether even here on earth, all mutations are random with respect to the environment. I can envision a set of circumstances in which, say, Lamarckism holds, or something we have never considered.

Why would natural selection stop working as an evolutionary mechanism?

How could Lamarckian evolution work?

https://www.sciencedirect.com/science/article/pii/S0079610719301129

That paper is speculation. There is no confirmed evidence for a mechanism for this to actually occur. They suggest horizontal gene transfer could explain it, but that happens in microbes, and its relevance to Lamarckian evolution is speculative. The paper also assumes that genetic material can survive travelling through space, yet exposure to extreme amounts of radiation as well as the incredibly long times spans involved are significant barriers which the paper does not explain.

There seem to be features of biology that are already Lamarckian, such as microRNA and epigenetic features. In any case, I gave the link not only because this is the pseudoscience forum, a place for speculation and worse, junk claims, but also because of the way you asked the question: "[h]ow could..." You did not seem to be asking for proof or definitive answers, just speculation on mechanisms. So far as barriers, many things have barriers when it comes to evolutionary theories or life in general, but whenever there is a small probability of life succeeding over vast amounts of time and space there are many more opportunities for that one time for it to work out. And then once life takes hold, the very nature of life sustains itself.

 

[Loren Pechtel]

There seem to be features of biology that are already Lamarckian, such as microRNA and epigenetic features. In any case, I gave the link not only because this is the pseudoscience forum, a place for speculation and worse, junk claims, but also because of the way you asked the question: "[h]ow could..." You did not seem to be asking for proof or definitive answers, just speculation on mechanisms. So far as barriers, many things have barriers when it comes to evolutionary theories or life in general, but whenever there is a small probability of life succeeding over vast amounts of time and space there are many more opportunities for that one time for it to work out. And then once life takes hold, the very nature of life sustains itself.

I don't see how epigenetics is Lamarckian. We evolved genes that could in some cases react to prenatal conditions.

And while life takes hold in some pretty extreme conditions that doesn't mean it can stand up to interstellar voyages. While drifting between the stars there's no ability to self repair--and without it radiation damage will build up. For a human the lethal limit is only 500 years from internal exposure alone. Microbes are more resistant, they could go longer, but it will add up.