you do realize that humans cannot live in low G environments right? our bones lose calcium. moreover, what do you eat? you would have to create a bio-dome capable of supporting a large number of people in 0g. the amount of materials/fuel required to put that much stuff into space would be enormous, not to mention the difficulty of growing plants in 0g. the only real way to get a large number of people to live on another planet, would be to build most of your facilities on-site, with materials mined there. I think the lava tube ideas is good if they go down far enough to use Mars' core heat.
Extraterrestrial Humanity, 21st Century
- Thread starter Xylene
- Start date
Or just have a spinning station creating its own artifical gravity.
Just a few points...
1. Mars has a dead core, therefore no magenitic poles. Cosmic radiation on Mars would be fatal.
http://scienceworld.wolfram.com/astronomy/Mars.html
2. Melting the polar caps of Mar could in theory fuel a greenhouse effect making Mars habitable.
3. Most estimates put terra forming of mars at about 150,000 years.
4. Mankind only has about 150,000 years before yDNA inducted extiction
5. Lab experiments have shown that there are microbes on Earth now, that could produce a viable atmosphere on Venus, time span is about the same as terraforming mars
6. if you look at Dyson's well thoughtout list of galactic civilazations we are Type 0, what your discussing is a Type III civilaztion, something that we are thousands of years from.
Freeman Dyson, Disturbing the Universe, Harper & Row 1979, p 212
for fans of star trek..
Federation, Klingon, Romulians are all Type II
Borg Type III
Q.. hmmm off the scale
7. Intelligent Life and lack of contact. Our solar system is young by the standards of the universe. Even if you take into account that its likely that life can only develop on planets orbiting second generation stars, its likely there are civilazations that have billions of years on us. Radio waves to them might be and are likely to be as primative as drums on the Congo. their is no reason to expect that radio is the primary way of comunication in the galaxy.
8. Science has taught us time and time again to never say never, but in this case. Terraforming in the next century, we can be pretty sure that mankind will not take those steps, even if it in the natural course of action for a species that alters its environment to its needs and has a need to explore.
9. Solar winds unchecked by magnetic poles would strip any atmosphere on mars before it even had a chance to have an effect
1. Mars has a dead core, therefore no magenitic poles. Cosmic radiation on Mars would be fatal.
http://scienceworld.wolfram.com/astronomy/Mars.html
2. Melting the polar caps of Mar could in theory fuel a greenhouse effect making Mars habitable.
3. Most estimates put terra forming of mars at about 150,000 years.
4. Mankind only has about 150,000 years before yDNA inducted extiction
5. Lab experiments have shown that there are microbes on Earth now, that could produce a viable atmosphere on Venus, time span is about the same as terraforming mars
6. if you look at Dyson's well thoughtout list of galactic civilazations we are Type 0, what your discussing is a Type III civilaztion, something that we are thousands of years from.
Freeman Dyson, Disturbing the Universe, Harper & Row 1979, p 212
for fans of star trek..
Federation, Klingon, Romulians are all Type II
Borg Type III
Q.. hmmm off the scale
7. Intelligent Life and lack of contact. Our solar system is young by the standards of the universe. Even if you take into account that its likely that life can only develop on planets orbiting second generation stars, its likely there are civilazations that have billions of years on us. Radio waves to them might be and are likely to be as primative as drums on the Congo. their is no reason to expect that radio is the primary way of comunication in the galaxy.
8. Science has taught us time and time again to never say never, but in this case. Terraforming in the next century, we can be pretty sure that mankind will not take those steps, even if it in the natural course of action for a species that alters its environment to its needs and has a need to explore.
9. Solar winds unchecked by magnetic poles would strip any atmosphere on mars before it even had a chance to have an effect
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Huumm... could you further explain this?madoc said:
Why that long?
What is this about? Never heard of that....
Which microbes? What do they do?
Can you do the same thing for fans of star wars?
Again... some explanation....?
Peace out!
Yaba Daba :m:
1. the core of Mars and Venus are both dead, meaning that they have cooled to the point where they no longer are molten. A molten iron core is a requirement for a magentic pole. NASA has deduced that astronuats on Mars have about 500 days before they recieve a lethal dose of cosmic radation. This is the single biggest stumbling block to the terraforming of these planets.
3. Well, I can't lay my hands on the refernce materials at the moment. I am getting married and moving. However, I am fairly sure it is in the Space Exploration in the Next Century a NASA report. However in looking for an alternate source I did come across the work of Christopher McKay, who claims about 800 years to warm the planet. Quicker is it becomes a feedback system. However I do believe in the orginal report that the main bulk of the time line was ecological in nature, creating an earth like environment of plants and animals.
4. yDNA is dieing. Its poor self repair procedures, and massive mutations are slowly leading to men that are infertile. Dr. Sykes lays out an excellent case this in his book The Curse of Adam. There are those that claim yDNA is self repairing with its palindrome folding. However as Dr. Sykes pointed out..
if ACTTCA is correct..
and ACTTCT is the error..
when folded you have a 50-50 chance of getting
ACTTCA
TCTTCT
which for the most part is not important on yDNA since 80% of it is junk DNA
however if occurs in any of the vital areas.. the yDNA is not longer funcional.
Among all the species of mammials only one has succesfully left yDNA behind.
Naked Vole Rat.. all males are XX
Dr. Sykes also claims that at the current time we do have the abilty in very short order to produce a functioning XX human male.
This would require placing copies of SRY and other 'male' genes onto a X, but the end result would be a XX male with the ability to reproduce. becuase only men would carry the X 'adonis genes' there would be no problem with dupilcation.
5. Again I do not have the reference at hand. But here we go. One of the nitrogen fixing cyanobacteria was shown to at least in a lab survive and reproduce in the conditions present on Venus. These Nitrogen fixing cyanobacteria convert nitrogen and CO2 into nitrogen useable by plants and O2. One earth they are found in the most extreme of conditions. From deep sea vents to the insides of geysers. I do not recall which the species they were working with.
6. Nope.. sorry not a fan of star wars. However a guess would be Type III for the Republic/Empire
Type I has mastered all forms of terrestial energy. A truly planetery civiliaztion with on cooperative government
Type II Mastered stellar energy. Have explored and started to colonize nearby stars. (builders of the fabled Dyson Sphere)
Type III Truly Gallatic Civilization who have engery needs that can not be met by single stars.
9. Unchecked the Solar Winds would cuase atmospheric erosion, striping the terraformed atmosphere of vital gases. This is a large part of the reason that mars has an atmosphere that is only 1% of what ours is. Life on Earth is a result of a delicate balance and one of the main things that allows life to thrive here is the Van Allen belts, it protects us from radation and our atmospere from solar wind erosion.
points 3 and 5 I do not feel comfortable discussing without proper refernce material at hand, its been a long time. However I will try to get to the garage this afternoon and see if I can by chance lay my hands on the books which contain the info. Till then what I wrote is what I can remember of the materials, and should be taken with a grain of salt. Memories are not always what they should be, all people get old, and everyone dies, these are the realities of life
3. Well, I can't lay my hands on the refernce materials at the moment. I am getting married and moving. However, I am fairly sure it is in the Space Exploration in the Next Century a NASA report. However in looking for an alternate source I did come across the work of Christopher McKay, who claims about 800 years to warm the planet. Quicker is it becomes a feedback system. However I do believe in the orginal report that the main bulk of the time line was ecological in nature, creating an earth like environment of plants and animals.
4. yDNA is dieing. Its poor self repair procedures, and massive mutations are slowly leading to men that are infertile. Dr. Sykes lays out an excellent case this in his book The Curse of Adam. There are those that claim yDNA is self repairing with its palindrome folding. However as Dr. Sykes pointed out..
if ACTTCA is correct..
and ACTTCT is the error..
when folded you have a 50-50 chance of getting
ACTTCA
TCTTCT
which for the most part is not important on yDNA since 80% of it is junk DNA
however if occurs in any of the vital areas.. the yDNA is not longer funcional.
Among all the species of mammials only one has succesfully left yDNA behind.
Naked Vole Rat.. all males are XX
Dr. Sykes also claims that at the current time we do have the abilty in very short order to produce a functioning XX human male.
This would require placing copies of SRY and other 'male' genes onto a X, but the end result would be a XX male with the ability to reproduce. becuase only men would carry the X 'adonis genes' there would be no problem with dupilcation.
5. Again I do not have the reference at hand. But here we go. One of the nitrogen fixing cyanobacteria was shown to at least in a lab survive and reproduce in the conditions present on Venus. These Nitrogen fixing cyanobacteria convert nitrogen and CO2 into nitrogen useable by plants and O2. One earth they are found in the most extreme of conditions. From deep sea vents to the insides of geysers. I do not recall which the species they were working with.
6. Nope.. sorry not a fan of star wars. However a guess would be Type III for the Republic/Empire
Type I has mastered all forms of terrestial energy. A truly planetery civiliaztion with on cooperative government
Type II Mastered stellar energy. Have explored and started to colonize nearby stars. (builders of the fabled Dyson Sphere)
Type III Truly Gallatic Civilization who have engery needs that can not be met by single stars.
9. Unchecked the Solar Winds would cuase atmospheric erosion, striping the terraformed atmosphere of vital gases. This is a large part of the reason that mars has an atmosphere that is only 1% of what ours is. Life on Earth is a result of a delicate balance and one of the main things that allows life to thrive here is the Van Allen belts, it protects us from radation and our atmospere from solar wind erosion.
points 3 and 5 I do not feel comfortable discussing without proper refernce material at hand, its been a long time. However I will try to get to the garage this afternoon and see if I can by chance lay my hands on the books which contain the info. Till then what I wrote is what I can remember of the materials, and should be taken with a grain of salt. Memories are not always what they should be, all people get old, and everyone dies, these are the realities of life
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Oh, one more thing has came to mind. We all discuss terraforming as if its a word that has been arround forever, and has a precise defination. Well, ff Clinton showed us anything, its that one can never assume that they have a precise understanding of anothers defination of a word. So my question now is simple...
What is your defination of Terraforming?
Mine.. a precisely balanced planetery system that mymics that of the Earth in such a way that man does not have to interfere in its maintaince and that life from earth can thrive on, if they find the proper conditions of climate. (a polar bear in a rain forrest is screwed no matter if he is on Earth or Mars)
I know that others have had different opinions on the matter and I have seen terraforming schemes that call a barren planet in which one can work without a space suit but with supplemental oxygen complete.
What is your defination of Terraforming?
Mine.. a precisely balanced planetery system that mymics that of the Earth in such a way that man does not have to interfere in its maintaince and that life from earth can thrive on, if they find the proper conditions of climate. (a polar bear in a rain forrest is screwed no matter if he is on Earth or Mars)
I know that others have had different opinions on the matter and I have seen terraforming schemes that call a barren planet in which one can work without a space suit but with supplemental oxygen complete.
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We won't be doing anything but farming the Earth when we run out of fossil fuels.
Isn't there any material that could protect us against those cosmic radiations while we are working on it?madoc said:
Well, congrats! I've done that a couple of months ago....
Well, what is the probability of a mutation? Do you have any source for that?
There are many genetic diseases that are based on the y gene. Still, only a small percentage get them. So.... how come is it dieing?
That's true to all genes...
Wow! How does it work!?!?
How did that happen?
Eh?
Well, yeah. I thought so....
What are we? -1?
Could we create a "giant" panel to protect us?
Why would people want to live on Mars except for scientific research, (and you don't have to change an entire planet for that)? We have a perfectly good planet right here. It is not at all certain that our population will run out of room. And even if we were running out of room, how would we have the resources for such an ambitious mission?
This seems to be an extention of oil-era hubris and the dominator mentality that must seek ever more resources rather than living sustainably.
In the future I feel we will live on Mars, but it would be easier to adapt our bodies for Mars than adapt Mars to our bodies.
This seems to be an extention of oil-era hubris and the dominator mentality that must seek ever more resources rather than living sustainably.
In the future I feel we will live on Mars, but it would be easier to adapt our bodies for Mars than adapt Mars to our bodies.
1. any material to protect us while we are working on it. hmmm water, rock, lead, an atmosphere... all would reduce the level of cosmic radation, however to sheild a whole planet from it, you would need a very very large magnetic feild, one that could reproduce the effects of a molten iron core. While comsic radation is not a fatal blow to terraforming it is a serious technical hurdle.
3. Thank you
4a. I refer you to pages 274-305 of Adam's Curse by Bryan Sykes
4b. True, but with Y we have no backup.
4c. The species, which I incorrectly referred to as the Nake Vole Rat, is actually the Mole Vole, Ellobius lutescens As for how they managed this I don't know, but its a incredible feat. What is known is that they moved all their 'male' genes off the Y onto various parts of X, and did it just in time since Y is now gone from the species.
4d. Using the Mole Vole as an example. Dr. Sykes believes that the sperm producing geneomes can be moved to an X. This would require injecting the SRY and sperm producing genes into a XX embryo. It would not be an easy thing to do, but we now have the knowledge required to do it.
6. Michio Kaku, in Visions describes us as Type 0 - a planet that burns dead plants
9. Wow, if we could! It would have to be rigid to protect itself. It would have to let certain radation in. In short it wouldn't be fesible at the present. In fact if it was, we would be able to build a Dyson Sphere and all this would be pointless. A Dyson Sphere a huge artifical globe totally enveloping a star harnessing all of its energy output is the ultimate habitat for a spacefaring Type II civilazation. In both construction is an challenging issue.
3. Thank you
4a. I refer you to pages 274-305 of Adam's Curse by Bryan Sykes
4b. True, but with Y we have no backup.
4c. The species, which I incorrectly referred to as the Nake Vole Rat, is actually the Mole Vole, Ellobius lutescens As for how they managed this I don't know, but its a incredible feat. What is known is that they moved all their 'male' genes off the Y onto various parts of X, and did it just in time since Y is now gone from the species.
4d. Using the Mole Vole as an example. Dr. Sykes believes that the sperm producing geneomes can be moved to an X. This would require injecting the SRY and sperm producing genes into a XX embryo. It would not be an easy thing to do, but we now have the knowledge required to do it.
6. Michio Kaku, in Visions describes us as Type 0 - a planet that burns dead plants
9. Wow, if we could! It would have to be rigid to protect itself. It would have to let certain radation in. In short it wouldn't be fesible at the present. In fact if it was, we would be able to build a Dyson Sphere and all this would be pointless. A Dyson Sphere a huge artifical globe totally enveloping a star harnessing all of its energy output is the ultimate habitat for a spacefaring Type II civilazation. In both construction is an challenging issue.
Regarding the Y-chromosomes, while very enjoyable, Sykes did not provide conclusive data (neither in his book, nor in his publications). In fact, his calculation of 2% mutation rate is widely doubted. I do recall a paper in which this was rather severly challanged. Maybe I can find it on pubmed.
Edit:
1. Aitken, R. J. & Marshall Graves, J. A. The future of sex. Nature 415, 963 (2002).
2. Graves, J. A. The degenerate Y chromosome—can conversion save it? Reprod.
Fertil. Dev. 16, 527–-534 (2004).
Generally a timeline of 9-10 million years have been proposed
Edit:
1. Aitken, R. J. & Marshall Graves, J. A. The future of sex. Nature 415, 963 (2002).
2. Graves, J. A. The degenerate Y chromosome—can conversion save it? Reprod.
Fertil. Dev. 16, 527–-534 (2004).
Generally a timeline of 9-10 million years have been proposed
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It is a false assumption to think that continued mutation of the Y chromosome will lead to species extinction.
Each male individual of the species has his own unique Y chromasome. A mutation should affect only him and his descendants. You can't expect a mutation to hit the whole planet at once. Now, if the mutation is bad enough to be either fatal or enough to render the bearer sterile, the individual will not be able to breed. Thus, he will not be able to pass any of the truely nasty mutations on.
All the really bad mutations die out, leaving functional (if not perfect) genes behind for the rest of the genepool. Life goes on for the species as a whole.
As for colonizing places like Mars, I really can't see why it wouldn't be possible. Mars at one point had a full atmosphere and liquid water and it took a full billion years for it to become the dessicated hulk it is now. If, somehow, you could recharge the planet with volitiles, it would be good for another billion years. More than enough for our purposes.
While we are working our magic, we can make do with world houses. Just cap off martian craters, seal the edges, and pump in your volitiles. You have just made a tiny simulacrum of home.
Frankly, we need off this planet if we wish to survive. Its too small and cramped in this day of interconnectedness. If you put too many rats in a single cage, they go mad and will die at each other's teeth. If we don't spread out soon, our species will be extinguished in a blaze of fire and blood at our own hands. And, if by some miracle we manage to somehow restrain ourselves, a rock or a supervolcano or a plague will take us out just the same.
Each male individual of the species has his own unique Y chromasome. A mutation should affect only him and his descendants. You can't expect a mutation to hit the whole planet at once. Now, if the mutation is bad enough to be either fatal or enough to render the bearer sterile, the individual will not be able to breed. Thus, he will not be able to pass any of the truely nasty mutations on.
All the really bad mutations die out, leaving functional (if not perfect) genes behind for the rest of the genepool. Life goes on for the species as a whole.
As for colonizing places like Mars, I really can't see why it wouldn't be possible. Mars at one point had a full atmosphere and liquid water and it took a full billion years for it to become the dessicated hulk it is now. If, somehow, you could recharge the planet with volitiles, it would be good for another billion years. More than enough for our purposes.
While we are working our magic, we can make do with world houses. Just cap off martian craters, seal the edges, and pump in your volitiles. You have just made a tiny simulacrum of home.
Frankly, we need off this planet if we wish to survive. Its too small and cramped in this day of interconnectedness. If you put too many rats in a single cage, they go mad and will die at each other's teeth. If we don't spread out soon, our species will be extinguished in a blaze of fire and blood at our own hands. And, if by some miracle we manage to somehow restrain ourselves, a rock or a supervolcano or a plague will take us out just the same.
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Ophiolite
Valued Senior Member
Agreed. Multiple baskets for the eggs. A diverse stock portfolio.
As for repleneshing the Martian ecosphere, all we have to do is direct many Oort cloud comets to impact with Mars: hey presto water, volatiles and organics all in one handy package.
The same technique could be used on the moon and if all the impacting bolides are carefully directed we could spin it up to a more reasonable rotational speed and acceptable day length.
As for repleneshing the Martian ecosphere, all we have to do is direct many Oort cloud comets to impact with Mars: hey presto water, volatiles and organics all in one handy package.
The same technique could be used on the moon and if all the impacting bolides are carefully directed we could spin it up to a more reasonable rotational speed and acceptable day length.
The moon, on the other hand, has such a low surface gravity that it would only hold onto an atmosphere for perhaps ten thousand years. Still long enough for our purposes, but it presents some nasty theoretical problems for the future. It is hard to charge a planetary body with volitiles on a mass scale when there are people living all over the rock in question. No vaccine has been made for falling rocks.
Bad Mutations die out? I will be sure to tell that to all those people suffering genetic disorders. Bad mutations do not have die out, they only die out if they are lethal or prevent reproduction.
1940s 50% of all men had sperm count of greater then 100 million
1990s 16% of all men had a sperm count of greater then 100 million
1940s 6% of all men had a sperm count of less then 20 million
1990s 18% of all men had a sperm count of less then 20 million
Now as for the cuases of this.. well there are a tons of them evironmental, genetic, fertility treatments passing genes that would not have passed on.
Lets assume that 7% of men are infertile
now lets assume that 1% of all men are infertile becuase of yDNA mutation
now not all yDNA mutations cuase infertility.. in fact most would cuase nothing, but lets assume that 1% of these cuase their sons to be 10% less fertile then their fathers
taking only the yDNA mutations the fertility of the species is reduced .1% per generation. plot it out and you get fertility for mankind that is 1% of the current rate in about 5000 generations.
Maybe CharonZ can explain it better then I.
Ok, lets crash a bunch of stellar bodies into mars and venus. please explain how that plan deals with the following?
1. life is dosed with lethal radation.. still no magnetic core
2. solar wind erosion
As for pie in the sky schemes that are not possible at the momemt.. I could in theory with unlimited engery, materials, and time terraform venus.
1. pump 4×10^19kg of hydrogen into the atmosphere of Venus to convert the atmosphere via Bosch reaction
CO2(g) + 2 H2(g) → C(s) + 2 H2O(l)
2. stike Venus with an impactor of 700km diameter at greater than 20km/s
3. wait for everything to cool down while creating bioengineered microbes to finish the job
4. install gaint magnetic generators at the poles
Again as I stated before, terraforming and moving off earth is the ultimate fate of a species that has a need to explore and change its environment to its need. However I do not see us overcoming the hurdles involved in the next 100 years. I firmly believe that unless a major breakthrough in science that we can not even imagine at the current time comes about in next century, it will not be possible in the time span that the orginal post asked about.
Another piont that hasn't even been mentioned that is probally the largest hurdle is funding. Who is going to pay for it???
1940s 50% of all men had sperm count of greater then 100 million
1990s 16% of all men had a sperm count of greater then 100 million
1940s 6% of all men had a sperm count of less then 20 million
1990s 18% of all men had a sperm count of less then 20 million
Now as for the cuases of this.. well there are a tons of them evironmental, genetic, fertility treatments passing genes that would not have passed on.
Lets assume that 7% of men are infertile
now lets assume that 1% of all men are infertile becuase of yDNA mutation
now not all yDNA mutations cuase infertility.. in fact most would cuase nothing, but lets assume that 1% of these cuase their sons to be 10% less fertile then their fathers
taking only the yDNA mutations the fertility of the species is reduced .1% per generation. plot it out and you get fertility for mankind that is 1% of the current rate in about 5000 generations.
Maybe CharonZ can explain it better then I.
Ok, lets crash a bunch of stellar bodies into mars and venus. please explain how that plan deals with the following?
1. life is dosed with lethal radation.. still no magnetic core
2. solar wind erosion
As for pie in the sky schemes that are not possible at the momemt.. I could in theory with unlimited engery, materials, and time terraform venus.
1. pump 4×10^19kg of hydrogen into the atmosphere of Venus to convert the atmosphere via Bosch reaction
CO2(g) + 2 H2(g) → C(s) + 2 H2O(l)
2. stike Venus with an impactor of 700km diameter at greater than 20km/s
3. wait for everything to cool down while creating bioengineered microbes to finish the job
4. install gaint magnetic generators at the poles
Again as I stated before, terraforming and moving off earth is the ultimate fate of a species that has a need to explore and change its environment to its need. However I do not see us overcoming the hurdles involved in the next 100 years. I firmly believe that unless a major breakthrough in science that we can not even imagine at the current time comes about in next century, it will not be possible in the time span that the orginal post asked about.
Another piont that hasn't even been mentioned that is probally the largest hurdle is funding. Who is going to pay for it???
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Solar wind erosion takes forever and a day to occur. Like I said, one billion years for mars and ten thousand for the moon. Radiation would be no problem. We have bacteria here on earth that live in reactors, for heaven sakes. Splice adaptations like that, among others such as opaque skin, into colonists when they leave for their new home.
I admit that Venus is a tough one. Large quantities of calcium or magnesium would sequester CO2 in the form of carbonates. Again, this would certainly not be economical.
I admit that Venus is a tough one. Large quantities of calcium or magnesium would sequester CO2 in the form of carbonates. Again, this would certainly not be economical.
Ophiolite
Valued Senior Member
Your ten thousand figure for atmospheric retention seems wrong. I did some back of the envelope calculations years ago that suggested it would be one or two orders of magnitude higher. Do you have a source for the 10k figure. (It will save me finding that envelope!)
Ophiolite: Sorry. Its been years since I saw the figure the first time I saw it and I can't even remember the name of the article now. A quick browse through google seems to mostly give figures between 10k and 100k years... once you sort through the crap.
Nads: That is another topic entirely. We aren't talking about life naturally occuring somewhere. We are talking about forcefully shaping a rock so that it can support life and then seeding it directly. No random chance involved.
All you really need for life (as we know it) is a rock the right size orbiting a star at the right distance to keep it within a certain temperature range. Water is a damn common element, so that isn't a problem. Heck, Mars was ripe for life for a full billion years. Two planets capable of supporting life around one sun? What are the chances...
Nads: That is another topic entirely. We aren't talking about life naturally occuring somewhere. We are talking about forcefully shaping a rock so that it can support life and then seeding it directly. No random chance involved.
All you really need for life (as we know it) is a rock the right size orbiting a star at the right distance to keep it within a certain temperature range. Water is a damn common element, so that isn't a problem. Heck, Mars was ripe for life for a full billion years. Two planets capable of supporting life around one sun? What are the chances...
Clockwood,
possible extinction by Y-chromosome deletions is actually one possible outcome.
Y-chromosomes cannot regain information by homologous recombination (at least not in the usual rates). This is enhanced by the fact that mutations appear to accumulate rather rapidly on Y-chromosomes.
It won't result in sudden extinction, but, as you pointed out yourself mutations will be given to the next generation. Therefore there might, as I suppose you wanted to point out, either be a strong pressure to retain fertility determinants or replacement by new determinants (thus possibly replacing the current human race if cross-hybridization is impossible).
Another possibility is that despite the strong selection the fertility determinants still get lost (as e.g. fertile males decide not to breed).
If the pool of fertility determinants gets too low events like genetic drift might occur, possibly leading to extinction.
However, this is a process that will at most happen in a few million years.
The gist is given in this abstract, together with a possible mechanism that might advert it (though the author rather argues against it):
"The human Y chromosome is running out of time. In the last 300 million years, it has lost 1393 of its original 1438 genes, and at this rate it will lose the last 45 in a mere 10 million years. But there has been a proposal that perhaps rescue is at hand in the form of recently discovered gene conversion within palindromes. However, I argue here that although conversion will increase the frequency of variation of the Y (particularly amplification) between Y chromosomes in a population, it will not lead to a drive towards a more functional Y. The forces of evolution have made the Y a genetically isolated, non-recombining entity, vulnerable to genetic drift and selection for favourable new variants sharing the Y with damaging mutations. Perhaps it will even speed up the decline of the Y chromosome and the onset of a new round of sex-chromosome differentiation. The struggle to preserve males may perhaps lead to hominid speciation."
In other words, the Y-chromosome is an unstable element that might lead to:
- speciation
-extinction
both of which lead to an end ofthe human species (as it is), unless, there are some recovery mechanisms that have not been determined yet.
possible extinction by Y-chromosome deletions is actually one possible outcome.
Y-chromosomes cannot regain information by homologous recombination (at least not in the usual rates). This is enhanced by the fact that mutations appear to accumulate rather rapidly on Y-chromosomes.
It won't result in sudden extinction, but, as you pointed out yourself mutations will be given to the next generation. Therefore there might, as I suppose you wanted to point out, either be a strong pressure to retain fertility determinants or replacement by new determinants (thus possibly replacing the current human race if cross-hybridization is impossible).
Another possibility is that despite the strong selection the fertility determinants still get lost (as e.g. fertile males decide not to breed).
If the pool of fertility determinants gets too low events like genetic drift might occur, possibly leading to extinction.
However, this is a process that will at most happen in a few million years.
The gist is given in this abstract, together with a possible mechanism that might advert it (though the author rather argues against it):
"The human Y chromosome is running out of time. In the last 300 million years, it has lost 1393 of its original 1438 genes, and at this rate it will lose the last 45 in a mere 10 million years. But there has been a proposal that perhaps rescue is at hand in the form of recently discovered gene conversion within palindromes. However, I argue here that although conversion will increase the frequency of variation of the Y (particularly amplification) between Y chromosomes in a population, it will not lead to a drive towards a more functional Y. The forces of evolution have made the Y a genetically isolated, non-recombining entity, vulnerable to genetic drift and selection for favourable new variants sharing the Y with damaging mutations. Perhaps it will even speed up the decline of the Y chromosome and the onset of a new round of sex-chromosome differentiation. The struggle to preserve males may perhaps lead to hominid speciation."
In other words, the Y-chromosome is an unstable element that might lead to:
- speciation
-extinction
both of which lead to an end ofthe human species (as it is), unless, there are some recovery mechanisms that have not been determined yet.
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