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The Origins Of Life On Earth

J

Justin_Anstey

Gone But Not Forgotten
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What do you all think about this idea of microbial life being common throughout the universe and the recent claims that it continuously rains down on the earth at a rate of 1/3 ton everyday?

-First Evidence Of Life Coming From Space Reported
Http://unisci.com/stories/20013/0730011.htm

-Scepticism greets 'space bugs' claim
http://news.bbc.co.uk/hi/english/sci/tech/newsid_1466000/1466477.stm

If it is confirmed then could all life throughout the universe have a common origin?

I recall hearing some expert or other stating that they thought the formation of biological life would be so unlikely that it may only happen once in the lifetime of the universe. Maybe that is true but it happened elsewhere.

Perhaps this bacterium could only develop in a very particular, comparatively temperate, environment like it did here on earth. As such, would the large, increasingly complex organisms that could go on to develop intelligence evolve along the similar lines we did? That is, initially thriving in the same kind of places, i.e. (I could be completely wrong about this) in oceans of water, leading to a uniform series of development: long bodies with about four limbs, the head at the front end, etc.. Maybe it could even result in a humanoid form.

Is there intelligent life out there, in the form of people knowledgeable about biology?

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Also, I am pretty certain that I saw on this site a 'Breaking News' article about creationists giving in to the idea of evolution but holding onto the notion that god created the first bacterium. I'm not sure if they were prominent members of their kind or even if they were members of a major organised group. I would like to read this story again, it seems like it may be a figment of my imagination.

If I'm right, is the fact that they were willing to give up so much ideological ground a step in the right direction? Would it take another one to accept the idea that it wasn't created on earth?

-Justin.
 
Justin Anstey said:
If I'm right, is the fact that they were willing to give up so much ideological ground a step in the right direction? Would it take another one to accept the idea that it wasn't created on earth?
Click to expand...

And then another to accept it hadn't happened 6,000 years ago, presumably (it is the creationists who believe this, isn't it?)

I don't know much about biology, but I know it's long been postulated that extra-terrestrial organisms could be the cause of some of the disease outbreaks on Earth. One of the better known was the sleeping sickness outbreak in the '30s, where people just feel asleep and never woke up for decades (some never did, and I think some might still be asleep).
 
The normal creationist stance is to accept evolution within "kinds", that is, a reptile can evolve into another reptile, a rodent into another rodent, but a reptile cannot evolve into a mammal. of course new fossil evidence is making this more difficult for them, but I'm sure they'll find a way round it...
 
Yes, they are all supposed to be the remains of creatures drowned in the flood, or sometimes a previous creation, (God having a practice?).

Then, there is always a missing link. Simply, pick any gap in fossil records & defy scientists to fill it, THEN if they do pick a further gap & so on!!!!
 
But how can Microbial organisms travel thorough the vacuum of space to reach us here on earth? Surely they need a medium to grow on and other factors to enable it to reach earth?
 
Many bacteria can go into a spore-like state of almost suspended animation, during which they can survive possibly thousands of years without even water. There was a news story in New scientist within the last year, when some scientists got a nasty shock when they reanimated some very very old bacteria. Luckily they weren't dangerous.

I'll do some digging and see if I can't back this up for you.
 
OK guys, something i can possibly reply to intelligently. I did a bit of digging into the whole Bacillus permians thing for an undergraduate essay i had to write on genetic technology. My own view is that there is something very unlikely about it. 250 million years is a long time (long enough for entropy to turn anything into it's constituent atoms).
I would be perfectly willing to accept this if the genome of B.permians was completely different to modern day species of bacteria but the fact that it is very similar to a type of bacteria that is able to survive in hi-salt environments makes it seem much more likely that this is a new guy that just made the rock crystal his home.
The idea of panspermia (life being "seeded" from elsewhere) has been around for a while. I think it was first postulated by one of the more famous astronomers, i dunno- Hoyle or Drake or someone.
It's a good idea but again i reckon it's more likely they have travelled the 20 or so miles up from earth than the couple of billion miles across space.
As to a similar origin of life leading to similar lifeforms throughout the universe if it were true it could be possible to an extent. Convergent evolution often rules on earth. Where species occupying similar ecological niches end up with a similar kind of body. e.g the wolf and the tasmanian tiger. One is a placental mammal and the other is a marsupial mammal. The particular animals have not had a common ancestor for more than 20 million years but the end product of a particular lifestyle (i.e. hunting small animals) results in a very high degree of (superficial) similarity.
If life could only develop on planets similar to earth then possibly there could be a kind of universe wide convergent evolution.
However the large degree of randomness that goes on during evolution to determine the appearance of a species makes it still unlikely (but not impossible).
 
Hoyle certainly proposed it and Chandra Wickramasinghe (the chap heading the group at Cardiff that has made the claim) was one of his students, and a key proponent of the theory. (As a sideline, they were both opposed to the Big Bang theory of the universe.)
 
I read something the other day about how in ice formations similar to what you can find in certain nebulas, if you add sunlight the molecular structures increase in complexity. I couldn´t help but wonder if it is possible for life to start off in a nebula, and if so what it would end up looking like.

But I´d say that life almost certainly has happened elsewhere, and I see no reason why they can´t travel with comets. Think about those microscopic bear-like animals, they can survive anything.
 
You mean Tardigrades? Those things kick ass. Have you seen the electron micrograph of them in their suspended animation and natural states. Tough little guys for sure. I have always been amazed at how such a complex (relatively speaking) animal can survive what some individual cells cannot.
 
It´s kind of embarrasing but I can´t remember what they´re called. But they do look like little bears. I would like to know if they have done any sort of photographs of hibernating tardigrades and compared them to photos of live ones. Just to see what physiological differences there are, since they apparently appear dead untill awaken.

There´s also the Cell from Hell, that should also be able to survive everything.

But what about entropy, how can they hibernate for so long without being damaged by that? Especially if that pterodactyl in a rock is true, that must have been in there for ages.
 
well the pics i saw. when they were in suspended animation they were kind of a thin blob with no legs exposed. on rehydration they become like mini bears.
I dont know if entropy would come into it as its the extremes of temp, pressure and lack of water they survive thats interesting
 
I thought entropy meant a Yeatesian 'Things fall apart...',

8 ¬)
 
Tardigrades

Strangely enough (I suppose not, this being a Fortean board) I have a photo of a Tardigrade sitting above my desk (not so strange in that I'm an entomologist but...).

There was a big paper on them in NATURE v. 395, p. 853 and a small article in the New Scientist the same week - which is where my photo came from.

As for panspermia - I don't see how this helps creationists at all. The bible has life created on Earth and in defined steps. Bacteria from space aren't in Genesis so wouldn't I assume, fit into any sort of Fundamentalist world-view whether they were young Earthers, Old Earthers or whatever.
 
I find that it's the only explanation for the existence of life and our origins that makes any sense to me -- that we evolved through a long, long time through mutations until we have taken our form today. We'll likely evolve some more, if we're still around in 10 million years.

I also read something interesting a few weeks ago (sorry, I can't exactly remember from where but I think it was space.com or something): that when neighbouring stars go supernova, they emit radioactive chunks and they thought that it's something that facilitates evolution -- and that it wipes out existing more-evolved species with the intensity in radiation and asteroid impacts (the asteroids that come from these neighbouring supernova stars contain high amounts of radiation). They said that one of the mass extinctions occurred around the time that some neighbouring galaxy of ours went supernova and that's how they came upon this <theory of factoid?>.

Did anyone see any articles in the last few weeks about this? I'm going from memory and I wish I would've saved where I saw it.

But if i'm recalling correctly, the chances are if we can determine about when stars go supernova and if look around neighbouring solar systems, we MIGHT find be able to find more complex lifeforms if these micro organisms are everywhere and can land on planetary bodies at any time. If there are so many of them, all you'd need is a catalyst. (kind of like Sea Monkeys, or brine shrimp, that are frozen -- just add water and voila! instant colony)
 
Do you have any idea how long it would take an asteroid to get here from a neighbouring galaxy? The light might be able to do it, but asteroids probably wouldn't even be here yet. If they move slowly it takes a damn long time. And if they move fast they'd probably get smashed up in the meantime.
 
Probably millions or billions of years (for some asteroid to get here from the next nearest solar system). Maybe it was something along the lines of radioactive particles -- but it has something to do with mass extinctions and massive mutations . I thought it said that (whatever those were -- radiotactive particles or bits of rock?) contained enough radiation to accelerate mutation from one generation to another and speeds up the time it takes to have enough biodiversity and give rise to different species (?).

I don't know this with certainty -- I might be confusing it with something else altogether.
 
Well, you need a certain mutation rate to have life. You need them to mutate every once in a while to have variation. But also to be able to pass these newly found thingsnonto their children without it mutating again. Of course a short burst of radiation might be good.
 
(hypothetically) if the lifespan of the (simple) organism to be mutated (when these rays come around), has a lifespan of 30 days, and they are able to reproduce around the 15th day, many generations can go by in a year alone.

If lots of the organism (before the mutation, with the same physiology) existed and they were exposed to about the same level of radiation, a percentage would undergo the same (?) mutation, I'm guessing it would account for a sub-population existing with the mutation.
 
i think what phgnome is talking about are gamma-ray bursts. They are nasty. It depends on the intensity of the burst but as far as i know all species will be affected but those with faster reproductive times e.g. bacteria, will be able to cope with the mutagenising radiation better as they can get through more generations quicker than anything else and this allows natural selection to work faster on them. This will allow them to evolve better anti-radiation defences (which btw all cells, including humans, already have). The radiation doesnt cause them to evolve anything other than a better defence against it so they dont die. Once it has equilibrated it will still be the ecological niches the organisms occupiy that determines biodiversity.
 
Thanks, barnadad -- I've been racking my brain out this past week trying to remember what they were.
 
Gamma ray bursts, or any radiation, would not just result in an evolved resistance to radiation - although this would occur if their were resistant organisms around.

The radiation would also cause random mutations. Most of these would be harmful but some may result in mutations that gave an advantage in various environments.
Environmental niches don't determine evolution - genetic mutation does. Those mutations that give an advantage to individuals allow them to propogate better in a particular niche. It's a feedback system but the ecological niche itself cannot force an individual to change and then propogate that change - that's Lamarkism.

Pete
 
mate, i'm not a lamarckist. i didnt say the environmental niches determine evolution- i said the environmental niches determine biodiversity. In that the more available niches the more likely it is that natural selection will allow numerous different organisms to evolve. The more possible ecological spaces to fill the easier it is for species to avoid competition by exploiting different things.
 
My misreading then - apologies for the "L" word!

It seems to me to be a finely balanced thing - the evolution of radiation resistance is necessary to prevent total extinction but - from a purely speciest point of view! - life on Earth would be dull if that resistance was 100% effective. If mutation relied on internal copying errors then we'd have less diversity in terms of comlex organisms - things like gamma ray bursts, geological radiation and the rest seem to be the cause of the large-scale, rapid mutations that make life so interesting.

Sorry if I caused any offense - wasn't intentional.

Pete:eek:
 
All is forgiven. Although i do have a bit of respect for old Lamarck. He was the first to go against the immutable divine creation idea and for that he should be applauded.
 
While Germs in Space is an intriguing hypothesis, even if not disproved, there is simply no compelling reason to believe it is true and plenty of reasons to be doubtful.

While it is mathematically theorectically possible to somehow sneeze germs over to the next solar system whether this ever actually happens or is actually likely to ever happen before the heat death of the universe is another story.

Ubiquitous life in the interstellar medium looks more like evidence that life should be easy to create on warm wet worlds to my mind. I expect someday we would find the spores lying all over the surface of Mars and the Moon when we do proper experiments. When we find something that doesn't use ATP, I will take notice.
 
Life's building blocks created in space simulator

The building blocks of proteins, amino acids, can be generated in the chilly conditions of interstellar space, suggesting the ingredients for life are universal.
"This means they aren't just in our Solar System," says Max Bernstein of the SETI Institute and the NASA-Ames Research Center, both in California. "I'm confident they are in planetary systems throughout the Universe." ...
Click to expand...

Do you think that means they are confident there's life as we know it? Or just a few splodges of protein?

More here. :)
 
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