How life might have started on Earth:

Originally posted by humy
Not sure but; for the very first protocell to be viable, an RNA-like molecule rather than proteins must have been used first and that's because, as far as we know, protein's cannot so easily readily and spontaneously function as carrier of genetic information (although I think it is theoretically possible for them to do so ) .
I think RNA, or, much more likel ...[text shortened]... generic material at the same time -or at least that is my (and some other peoples ) best theory.

Special proteins have to be available in the beginning to copy part of the DNA information into an RNA strand needed to make a protein. So the proteins and the DNA information must be there at the same time in the beginning by design. RNA strands come later.

The Instructor

Originally posted by humy
Not sure but; for the very first protocell to be viable, an RNA-like molecule rather than proteins must have been used first and that's because, as far as we know, protein's cannot so easily readily and spontaneously function as carrier of genetic information (although I think it is theoretically possible for them to do so ) .
I think RNA, or, much more likel ...[text shortened]... generic material at the same time -or at least that is my (and some other peoples ) best theory.

One question I have, if life started as a result of those hot vents, how could it have evolved to live at lower temperatures and different chemistry of the surrounding ocean?

Originally posted by sonhouse
One question I have, if life started as a result of those hot vents, how could it have evolved to live at lower temperatures and different chemistry of the surrounding ocean?

I know of the theory that life started in hot vents but I think this would be very unlikely because molecules and membranes tend to be much less stable at higher temperatures and polymerization of organic molecules tends to happen more at lower temperatures. Much more likely I think that life started in a relatively cool tidal pool.

However, if life did start in a hot vent and evolved to survive there then, in answer to your question:
there is always a temperature gradient and therefore an intermediate zone (a microenvironment ) between wherever it is hot, such as in a hot vent and where it is a lot colder, such as the cooler water and rock surfaces just adjacent to a hot vent. So, once the first living cells evolve to withstand high temperature of the vent, the ones that inevitably venture in the zone sandwiched between the hot and the cold zones, even if that zone in-between the other two is just, say, only one millimetre in thickness, will start to incrementally evolve tolerance to colder and colder temperatures and, as they do so, slowly push their way further and further towards the cold zone until they are able to tolerate and thrive in the cold zone.

But, personally, because I think life is more likely to have originated in a cooler environment, I think it is more likely it happened the other way around; first life evolved to thrive in relatively cool environment and then, via venturing into the in-between zone between the hot zone of the hot vents and cold zone of the environment adjacent to them, evolved the heat tolerance needed to survive in hot vents.

Originally posted by humy
I know of the theory that life started in hot vents but I think this would be very unlikely because molecules and membranes tend to be much less stable at higher temperatures and polymerization of organic molecules tends to happen more at lower temperatures. Much more likely I think that life started in a relatively cool tidal pool.

However, if life did sta ...[text shortened]... of the environment adjacent to them, evolved the heat tolerance needed to survive in hot vents.

Or a third path: Life could have started in both environs around the same time where there was no occupation of either environ before life started so maybe simultaneously in both places.

The argument against that as I see it would be to have two totally different evolutionary paths and I doubt we would see such similarity in the DNA of these two different life forms.

So it seems to me, from an evolutionary stance, one developed first then spread to the other environment and evolved to survive there.

Originally posted by sonhouse
Or a third path: Life could have started in both environs around the same time where there was no occupation of either environ before life started so maybe simultaneously in both places.

The argument against that as I see it would be to have two totally different evolutionary paths and I doubt we would see such similarity in the DNA of these two differe ...[text shortened]... y stance, one developed first then spread to the other environment and evolved to survive there.

I think that analysis is sound. However, if life independently DID independently start in both the hot vents and in cooler environments elsewhere (I am not sure how one could explain the genetic similarities between the two sets of lifeforms. Perhaps parallel evolution? Or maybe genetic material was somehow exchanged between the two? ) then the implications are significant! For it would mean that life must surely spontaneously form virtually wherever there is liquid water and organic compounds and and a source of energy and that would mean life is common throughout the universe (else it would be a ridiculous coincidence that life formed independently at least twice on earth ) and so common that there is a good chance it once was on Mars and may still be there. If so, almost certainly only microbes I think and deep in Martian soil. Little creatures crawling on the surface ( like I have seen in some bad science fiction ) where the pressure would be too low for liquid water to exist even with a lot of antifreeze (thus blood and cytoplasm would either boil or freeze ) would be a biological absurdity I think .

Originally posted by humy
I think that analysis is sound. However, if life independently DID independently start in both the hot vents and in cooler environments elsewhere (I am not sure how one could explain the genetic similarities between the two sets of lifeforms. Perhaps parallel evolution? Or maybe genetic material was somehow exchanged between the two? ) then the implications are ...[text shortened]... thus blood and cytoplasm would either boil or freeze ) would be a biological absurdity I think .

Since we have literally only scratched the surface of Mars we may yet find active life, most likely bacterial, underground. I guess it will take humans with big rigs to dig deep enough, maybe a kilometer deep or so.

There is also the theory that life originated on Mars first and was brought to Earth by meteorites.

Originally posted by sonhouse
Since we have literally only scratched the surface of Mars we may yet find active life, most likely bacterial, underground. I guess it will take humans with big rigs to dig deep enough, maybe a kilometer deep or so.

There is also the theory that life originated on Mars first and was brought to Earth by meteorites.

There is also the theory that life originated on Mars first and was brought to Earth by meteorites.

Yes, I know. I think that theory is flawed for it doesn't help to explain anything because, if life independently started on Mars then why would be any less likely that it also independently started on Earth? And, If life didn't start on Mars then why would it be more likely to have started somewhere else other than on Earth? Answering one question (how life came to be on Earth ) by begging another (how life came to be at that other place other than the Earth ) doesn't help to explain much unless we have actual evidence for life on Earth originating from Mars (which we don't! I have yet to hear of the tiniest scrap of evidence that life came from Mars. We haven't even proven that life once existed on Mars! )

Originally posted by sonhouse
Since we have literally only scratched the surface of Mars we may yet find active life, most likely bacterial, underground. I guess it will take humans with big rigs to dig deep enough, maybe a kilometer deep or so.

There is also the theory that life originated on Mars first and was brought to Earth by meteorites.

Nope.

The Instructor

Originally posted by humy
I think that theory is flawed for it doesn't help to explain anything because, if life independently started on Mars then why would be any less likely that it also independently started on Earth?

Its a good hypothesis, but requires evidence before being taken as anything more.

Originally posted by twhitehead
Its a good hypothesis, but requires evidence before being taken as anything more.

Yes, of course, this is only supposition till evidence comes our way. There was that meteorite they found in Antarctica, NASA thought it had fossil life on it, but it seems to have been proven false or at least inconclusive due to the fact that non life processes could have made the forms seen.

Originally posted by sonhouse
http://phys.org/news/2013-10-chemists-life-earth-fluke.html#ajTabs

So much for the creationist argument that random events would never create life from scratch. It is CLEARLY not random but self organized. Another step on the road to completely understanding how life could have started here and then to create life from rocks.

This is the science forum. Could you restrict your cheerleading anti-creationism rhetoric to the Spirituality Forum ?

Originally posted by sonship
This is the science forum. Could you restrict your cheerleading anti-creationism rhetoric to the Spirituality Forum ?

And of course, posting the same thing there, you would just reply 'keep the science in the science forum, we don't want you here'.

As if you are actually interested in science, especially origins of life or evolution or age of the universe or Earth.

My anti-creationism stance is not based on religion, it is based on solid evidence. That makes it based on science.

Originally posted by sonhouse
And of course, posting the same thing there, you would just reply 'keep the science in the science forum, we don't want you here'.

As if you are actually interested in science, especially origins of life or evolution or age of the universe or Earth.

My anti-creationism stance is not based on religion, it is based on solid evidence. That makes it based on science.

You can be demonstrated in much error over here or over there.

Why should I not be interested in science, origins or Earth age ?
I can be just as interested as you and realize the limitations of science disciplines. Apparently you don't realize such limitations.

Originally posted by sonship
You can be demonstrated in much error over here or over there.

Why should I not be interested in science, origins or Earth age ?
I can be just as interested as you and realize the limitations of science disciplines. Apparently you don't realize such limitations.

Of course science can't know everything. But you are not interested in hearing about the discoveries that refute creationism. That is the difference between you and me.

I want to see where the sciences will lead us. You want to POINT science in the direction you want it to go in. You want to CONTROL science. I want science to control itself and reveal the truth.

You want to control science so your bible god is proven to be true. And you will never be able to see the difference.

Your mind is closed to the evidence of science. If the evidence points clearly to a multi billion year old universe, the evidence is flawed. If the evidence points to a 6000 year old universe, the evidence is self evidently true. That is how your mind works.

And of course your reply would be something like 'why do you think you know how my mind works? You don't even know the mind of god' and so forth.

Originally posted by sonhouse
Of course science can't know everything. But you are not interested in hearing about the discoveries that refute creationism. That is the difference between you and me.

I want to see where the sciences will lead us. You want to POINT science in the direction you want it to go in. You want to CONTROL science. I want science to control itself and reveal t ...[text shortened]... 'why do you think you know how my mind works? You don't even know the mind of god' and so forth.

And you don't even know your own mind. Right?

The Instructor