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Did Life Originate Underwater?
Posted by
timothy
on Wed Dec 04, 2002 03:28 PM
from the reheating-the-primordial-soup dept.
from the reheating-the-primordial-soup dept.
TuringTest writes "Sciencedaily reports a highly controversial new theory about the origins of life from Professor William Martin of the University of Dusseldorf and Dr Michael Russell of the Scottish Environmental Research Centre in Glasgow. The theory briefly states that inorganic cells where first, then living systems evolved inside these incubators which allowed an enough rich micro-environment. The small compartments would have been formed in iron sulphide rocks near hot, hydrothermal vents on the sea floor, not in the atmosphere. Wow, that would answer the chicken-egg problem."
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Did Life Originate Underwater?
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That's not important (Score:3, Interesting)
DNA (Score:4, Insightful)
As long as they have chromosomes, and use the same 4 genetic molecules, there is almost no possibility that they are not related to the rest of life on Earth. What are the scientific chances of two lifeforms forming and evolving, with identical genetic processes?
Re:That's not important (Score:5, Insightful)
This one is really, really hard to prove unless you can find the original life-bearing world from which the first cell originated.
Even if you manage that, you're still stuck back with the question of how life started on that world instead of this one. You might as well work on mechanisms for the origin of life on earth, since it remains the only world on which we are sure life has ever existed.
Irrelavent. (Score:5, Insightful)
Correction: It would be Highly Relevant (Score:4, Insightful)
1 - We would know it's a waste of time to try to figure out how life began in the universe in general by looking at the evidence available here on Earth.
2 - We would know life on other worlds must exist, or at the very least, must have existed in the past.
Re:Design, Intelligence, Absolute Ethics & Hot (Score:4, Insightful)
Im really fond of the last ditch efforts by judeo-christians to make Sense of Creationsism with the "Intelligent Design" drivel.
A baseless nonsequitor argument made to reinforce an irrational idea... absolutely fabulous. When this effort fails, maybe they will say that Aliens, guided by G-O-D (in my best booming -heavens voice) are responsible for life on earth.
The fact is, the judeo-christian mythology has lasted far far to long. When Presented with evidence of wrongs in the bible -- like the existence of dinosaurs for instance -- people try and explain away the problem. Let me tell you, if the bible is incorrect (wrong) because it omits mention of a realistic history of the planet (beyond all the poof-7-days-stuff) what else could be wrong? Judeo-christian mythology -- the basis for so much immorality and idiocy in history -- needs to fall the way of greek or roman mythology.
The romans put thousands of people on the cross who claimed to be gods-on-earth... why do you suppose one existed at all?
Let me tell you know then -- Im the son of the one true god. (you have as much reason to believe this random statment on
If nothing else makes my stomach wrench about the ill fate of humanity its religion.. every last damn one of them.
Chicken-egg problem? (Score:3, Funny)
No Problem.
Life underwater (Score:3, Insightful)
problems (Score:3, Funny)
No, it reduces the Q to "what was first : the fish or the egg ?"
It does offcourse open endless possibilities
Why did the fish cross the road ??????
Re:problems (Score:4, Funny)
A. It was stapled to the chicken.
Re:problems (Score:5, Insightful)
to get to the other tide?
So, which came first, the chicken or the egg.
(answer) hydrothermal vents. Ok, but a bit evasive.
Actually, I just wanted to say in general that if you believe in evolution, clearly the egg came first, as it was present in the chickens ancestors before the chicken evolved.
Actually, I think that's true even if you don't believe in evolution, since not believing in evolution doesn't make it less true.
Re:here we go.. watch my karma drop to nill (Score:4, Informative)
No logic doesn't. Especially not once understands how DNA binding actually works and takes a glimpse into all the things that can change that process. Did anyone at your debate mention HSPs? Virus mutations that get auto-corrected? Those that don't? How the location of a string isn't nearly as important as the coding sequence? How much damage a sequence can take and still be effective?
You are creating a logical fallicy and then using that to argue your points. I realize that you are probably trolling but really, please go out and read up on DNA some and not just the often purposefully incorrect information on it passed around by "creation scientists".
Same principal as... (Score:4, Funny)
Re:Wow, (Score:5, Funny)
Hey, if you're really lucky, your story will get on the front page again in about 3 days!
Big deal -- this is the Primordial Soup theory (Score:3, Insightful)
Wake me when we find the answer.
Re:Big deal -- this is the Primordial Soup theory (Score:5, Informative)
Interesting article, if a bit short on details. A little bit more info is available here [royalsoc.ac.uk].
Re:Big deal -- this is the Primordial Soup theory (Score:5, Informative)
(*)Hall, D.O., Cammack, R. & Rao, K.K. (1974) The iron-sulphur proteins: evolution of a ubiquitous protein from model systems to higher organisms. _Origins_of_Life_, 5, 363-86.
Re:Big deal -- this is the Primordial Soup theory (Score:5, Informative)
***
For more information on Miller and prebiotic Earth, here is a quotation from an Angew. Chem. review article by Kay Severin called Hot Stones or Cold Soup? New Investigations on the Endogenous Origin of Organic Compounds on Earth (Angew. Chem. Int. Ed 2000, 39, No. 20). It pretty much sums up the Miller reactions, why they're wrong, and what people think now:
"The most famous experiment
"But the possibility that earth once had a reducing atmosphere is questioned. A well known argument against it is the high photolability of methane and ammonia. Because a shielding layer of ozone was missing a high concentration of these gases is believed to be unlikely. Furthermore, several other results point to a neutral atmosphere of CO2 and N2. Given the fact that the atmosphere was based on an unproductive mixture of CO2 and N2 the nutritional value of the primordial ocean drops significantly.
"An alternative scenario has been propagated for several years by [Gunter] Wachterhauser. Instead of a primordial soup he favors hot minerals as the place where organic molecules were initially built as life subsequently emerged. Especially sulfur-containing minerals like pyrite are proposed to have acted as an energy source and catalyst both under the extreme conditions found in hydrothermal or volcanic vents."
Basically, primordial soup syntheses (like Miller's reactions) are out and hot rock syntheses are in. These hot rock procedures have much much much lower yields, but people are slowly figuring out how to build amino acids through them. For instance, people, headed by Wachterhauser, have figured out how to carbon fixate (condense) carbon monoxide and carbon dioxide into organic building blocks for amino acids. For instance, in early 2000, Chen and Bahnemann were able to convert CO2 and water to small organics (acetaldehyde, ethanol, acetic acid) at high pressures and temperatures. Similarly, people have figured out how to take amino acids and convert them into peptides under high temperature and pressure situations.
However, to date no one has been able to actually make an amino acid through these techniques. As a result, the proof that amino acids were delivered by comets or meteorites (true fact, this is not an x-file) and now space dust, becomes much more appealing. Once the building blocks arrived on Earth, these hot rock syntheses could have taken over.
Was there enough water? (Score:3, Interesting)
If I am wrong, please correct me.
Re:Was there enough water? (Score:4, Informative)
Absolutely (Score:5, Funny)
Re:Absolutely (Score:5, Funny)
I have a friend who can't watch the Wizard of Oz for the same reason...
Headline is misleading (Score:5, Informative)
Underwater, UV was blocked, but longer wavelengths could penetrate to permit photosynthesis. Once photosynthesis liberated enough molecular oxygen to produce an ozone layer, life was able to move onto dry land.
What's novel about the theory in the article is that it proposes that living cells were preceded by nonliving inorganic cells.
Re:The guy is an idiot. More diversity in pools ab (Score:4, Insightful)
That being said, not all phylogenetic analyses support the thermophile-early hypothesis. That's because different genes may have different histories due to horizontal transfer. Further work on whole genome phylogeny will be useful for clarifying the issue.
Theories of Life Origin (Score:3, Insightful)
The first says that life formed in shallow pools, which would help shield harmful UV radiation.
The second is that it was carried to Earth from an extraterrestrial collision with something like a comet; this theory was supported but not proven by the pass-by of comet Hale-Bopp, i believe, due to the fact that spectrometry revealed that it had some organic substances (IIRC, our book has no mention of it).
The final theory (before the advent of this theory) is that life originated from volcanism at eep-sea vents. This would be supported by the life at deep-sea vents like tube worms and the like.
This is NOT to be confused with the 1953 experiment by Stanley Miller where he syntheized amino acids using lightning-like electricity and a proto-Earth atmosphere of methane, hydrogen, ammonia, and other gases. Amino acids are NOT life forms!
I think the title is a little misleading. This theory of life really means that life originated in porous underwater rocks, which is either an extension of the first theory or a completely new theory depending on how you view it.
Useful link for creationists and the rest alike (Score:3, Informative)
I think a lot of your questions about how evolution, cosmology, and the rest of science attempt to explain all sorts of phenomena (without resorting to a default "because of God") can be answered by visiting the Talk.Origins Archive [talkorgins.org].
If they can't be answered, there are some very helpful admins who answer most of the mail they receive with not only answers, but links to the source of the answers.
It's better than wading through the
What's New About This (Score:4, Informative)
A bit after the beginning, there were some self-replicating molecules. Some of them might have been proteins, and some of them might have been nucleic acids, and I suppose some of the might have been something we haven't thought of. The molecules that were really good at self-replication did it quite a bit, and there got to be more of them, especially when they had access to the necessary raw materials.
One day, or more likely on a large number of different days, a bunch of these self-replicating molecules all found themselves trapped together inside a sphere made of phospholipids floating in a puddle and started interacting in a synergistic kind of way.
The new story:
A somewhat shorter bit after the beginning, some basic molecules got spewed out of an ocean vent and all found themselves trapped together inside a sphere of rock at the bottom of the ocean. These basic molecules interacted a bit (thanks to their proximity) and formed some self-replicating molecules, which were of course trapped, too. The molecules that were really good at self-replication did it quite a bit, and there got to be more of them, which was easy because they had access to the raw materials they needed to self replicate (because said materials were, as we have said, trapped).
One day, or more likely on a large number of different days, a bunch of these self-replicating molecules all found themselves trapped together inside the same sphere of rock and started interacting in a synergistic kind of way. At some point they must have made their collective way into a phospholipid sphere, I suppose, or else our cell membranes would be made out of rock.
Re:Creation of Life (bwahahahaa) (Score:4, Insightful)
What we can do is collect evidence and conjecture theories about what caused the evidence.
Ultimately that is what atheistic cosmologists and Christian cosmologists do - collect data, and have a theory about what caused the data.
You may argue that Christian cosmologists have a bias. I would submit to you that scientists with an a priori commitment to materialism have a bias as well.
Respectfully,
Anomaly
Re:Creation of Life (Score:5, Funny)
Re:Creation of Life (Score:5, Funny)
Amazing that all those accidents of nature worked out just perfectly, isn't it? I think that is even more unbelievable than Creation.
A while back I heard a joke about how God and a bunch of Evolutionists were discussing the origins of life. The Evolutionists said they could show how to create life. God said to go ahead and show Him. They said "let's take some dirt and water and ..."
God interrupted and said "Wait a minute. That is My dirt and water. Go create your own."
Re:Creation of Life (Score:4, Interesting)
I'm not so sure that you can say this. Even some scientists who don't believe in a literal Adam and Eve have posited the existence of a single mother to all currently living humans, through the tracing of mitochondrial DNA (which inherit genetic infomation only through the mother.)
From a numerical standpoint, though, it is entirely possible. Let's just say for the sake of argument that the human race began from two genetically distinct humans, one male and one female.
Each parent contributes a single chromosome from each of 23 pairs; they each therefore can produce 2^23 distinct gametes. Therefore such a couple is capable of producing 2^46---or over 70 trillion---genetically distinct offspring.
Assuming no genetic mutations, subsequent generations of offspring would recombine the chromosomes in ways not possible for the first generation. With 23 pairs of chromosomes to select, and 4 choices to choose from in each pair, there is the potential for (4!/2!2!)^23 = 6^23---or almost 800 quadrillion---genetically distinct individuals.
That is of course assuming no mutation occurs; with mutation, these numbers can only increase. These numbers might decrease if the first man and woman were not fully genetically distinct, but I think we have some headroom to spare.
Re:Creation of Life (Score:4, Informative)
I think you're a little confused as to what they mean by this. "Mitochondrial Eve" was not, in her lifetime, significant in any way. She's only so in retrospect: in the hindsight that all other lineages from her generation eventually happened to die out. As other lines perhaps die out, a new "Mitochondrial Eve" could be, conceptually, crowned. That there must be such an individual at any given time is a mathematical certainty (you can reason it strickly from logic alone), but its not always the same individual, and it isn't the case that this individual's children only bred with each other. Not at all! It's simply that only lineages that include this particular female in them at some point, survive. The exact same thing is true for a "Y chromosome Adam." But again, you're thinking about it the wrong way if you think that he has anything to do with "Mitochondrial Eve," especially timewise. And, like ME, the designation could change to a different, more recent individual if certain lineages happen to die out.
Re:The Aquatic Ape (Score:5, Informative)
+5 interesting? Dammit, where's my moderator points for (-2, debunked pseudoscience)?
The Aquatic Ape theory has been been debunked so many times it's weird to see someone tossing it back out, even on /.. A nice, easy refutation is over at the Straigh t Dope [straightdope.com].
Couple of quick points:
Go now forth, free of muddleheaded thinking.
Re:The Aquatic Ape (Score:5, Informative)
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Claim: Human hairlessness is explained by an aquatic past
Fact: Humans' relative hairlessness is unlike aquatic mammals, because A) most aquatic mammals aren't hairless; and B) those few that are have skin that's radically different from humans (there's a link for this in the seal skin and sweat section below).
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Claim: The pattern of human hair alignment is strikingly different from apes and indicates streamlining for swimming.
Fact: The pattern of human hair alignment is only very slightly different from apes. Also, in order for this pattern to indicate streamlining for swimming we would have to be swimming with the crown of the head facing straight forward and your arms held at your sides. Just take a look. This is so easy to see, you've got to wonder how AATers can make the claim, or why it's swallowed so uncritically. There's also the problem that humans are not even close to being fast swimmers to whom streamlining therefore might help (more info in the "hairlessness" link above).
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Claim: The human body responds the same to the act of standing up as it does to surgery or massive hemorrhage but this reaction doesn't occur when standing up in water.
Fact: Ooh, this is a thorny thicket; neither part is true but are misrepresentations of facts twisted about to make a point which isn't true sound true. To see how and why, you'll have to read this link on aldosterone and bipedalism.
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Claim: Only humans and marine mammals shed salty tears.
Fact: All primates shed salty tears (see tears link below).
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Claim: Only humans, Indian elephants, and aquatic mammals cry emotional tears.
Fact: Humans are the only mammals proven to cry emotional tears. There are no animals other than humans which have been scientifically proven as having emotional tears. However, there are unproved accounts of many other mammals crying emotional tears, but these are not just aquatic animals; they include dogs and wolves, seal, sea otter, lab rats, cats, cows, pigs, lambs, horse, a kangaroo and a gorilla.
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Claim: Only marine reptiles and birds have salt glands.
Fact:Salt glands are found in many non-marine reptiles and birds, including ostriches and other birds, and many lizards, including iguanas, chuckwallas, and others.
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Claim: The human response to salt indicates we evolved in a salt-water environment.
Fact: Human responses to salt are similar to terrestrial mammals, including chimps. Mammals which live in salt-rich environments do not exhibit these responses as humans do. Our salt mechanisms indicate a terrestrial past with a large herbivorous component to our diet, unlike the AAT claims.
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Claim: Human infants naturally swim while other non-aquatic mammals' infants can't.
Fact: The infant "swimming response" has been found in all mammals tested.
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Claim: Only humans and aquatic animals exhibit the "diving reflex".
Fact: The "diving reflex" is found in all mammals.
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Claim: Only humans and aquatic animals can hold their breath.
Fact: Non-human, non-aquatic animals can and do hold their breath (refs in diving reflex link above).
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Claim: The descended larynx of humans is like that of aquatic mammals, and must have arisen in an aquatic environment. Although it's necessary to make all the complex sounds we use in speech, it cannot have arisen for that purpose, because it wouldn't be useful for that purpose in its initial stages.
Fact: The descended larynx of humans is not particularly similar to those which are found in (only a very few) aquatic mammals (refs and info in diving reflex link above). The evidence from the fossil record also indicates that this feature developed several million years after the purported aquatic period.
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Claim: Non-human primates have nostrils that point forward, unlike humans.
Fact: What can I say; Old World primates are in fact called Catarrhine primates precisely because their nostrils face down. Morgan likes to try to have this one both ways; while she claims that forward-facing nostrils are detrimental to aquaticism, and that we had a human-like nose several million years before the bones on our ancestors' faces indicate they did, she takes the nose of both male proboscis monkeys (with its downward-facing nostrils) and of female and juvenile proboscis monkeys (which face forward) as aquatic adaptations. (Scientists who study these monkeys' behavior say it's sexual selection, as is true of all sexually dimorphic traits which aren't due to differences in use.) She even has a drawing of a juvenile proboscis monkey swimming in her latest book which, according to her theory, should have water shoved up his forward-facing nostrils. Why, if it's no problem for a monkey, would it be such a big problem for hominids as to force a massive change? Morgan doesn't see the contradiction.
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Claim: Our ancestors wouldn't have changed from quadrupedalism to bipedalism, because initially bipedalism would be less efficient than quadrupedalism.
Fact: Actual tests of chimpanzees by Taylor and Rowntree in 1973 (Science 176: 186-187) has shown that bipedalism is no less efficient for them than quadrupedalism. It wouldn't be for our ancestors, even if they evolved from knuckle-walking apes such as chimps. Also, the consensus over the last few decades has been that the LCA was far more likely to have been a brachiating (swinging from branches) ape rather than a knuckle-walker, which makes it even less of a problem to be bipedal. In fact, brachiating apes -- such as gibbons -- virtually always walk bipedally when they are on the ground.
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Claim: Proboscis monkeys use bipedalism more often than other primates and often walk bipedally as "merely an alternative locomotor mode of getting from A to B."
Fact: Morgan bases this claim on several seconds of film taken by Japanese filmmakers, which showed several proboscis monkeys walking bipedally. On this subject, I just (August 9, '01) watched a TV program, "The Secret World of the Proboscis Monkeys", and over the course of the hour, those obnoxious primates simply refused to do any bipedal walking. Perhaps it was because it was French filmmakers this time, or maybe the anthropological conspiracy quashed all the bipedal episodes. Or, just possibly, it's what years of observations by primatologists tell us: Proboscis monkeys don't walk bipedally more often than other primates (all primates use bipedalism occasionally).
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Claim: It was too dangerous for our ancestors to live on land during the transition from ape ancestor to hominid. The water provided safety from predators.
Fact: The water environment would be far more dangerous than the land environment; the predators there are more numerous and harder to deal with.
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Claim: Our ancestors couldn't have dealt with predators on land, because the only way to do so is to run away, and we weren't fast enough and there were no trees to climb.
Fact: Not only were there trees in the hominids' environment (see savannah definition if you haven't already), but it is unlikely we would have been limited to running from predators. How we probably would have handled them is how chimpanzees handle predators now (see the predators link just above).
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Claim: The body temperature of normal, healthy humans is the same as that of whales, rather than our primate relatives or other terrestrial mammals, and it doesn't fluctuate, while that of terrestrial mammals does.
Fact: The body temperature of normal, healthy humans is like that of our primate relatives, it does normally fluctuate, and it's not like that of whales.
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Claim: Hymens are an aquatic trait.
Fact: Besides humans, hymens are found in lemurs (fellow primates, you'll note), guinea pigs, mole rats, hyenas, horses, llamas, and fin whales. Except for fin whales, none of these mammals are aquatic. Also, AATers suggest that the reason for a hymen in humans was to seal off the female reproductive organs from waterborne parasites and such; but since the hymen is generally absent from the time of first intercourse (and very often before) this protection wouldn't be available for much of the female's lifespan.
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Claim: Vibrissae (sensory whiskers) are absent only in humans and in aquatic mammals.
Fact: Among aquatic mammals, vibrissae are actually absent only in some types of whales (whales such as blue, fin, and humpback whales have them) and of course they are abundant and very sensitive in most aquatic mammals. They are, however, also absent in other, terrestrial, mammals, such as tree shrews and the monotremes (platypus and echidna). The great apes have few vibrissae compared to other mammals, and their absence in humans seems to be yet another of the "continuation of a trend" features we see in primates (hair and sweat glands are other such features). A few minutes search on the web (using the term "vibrissae" with either "primates", "comparative", or "whales") easily turned up this information. Why do AATers not do even so easy and basic research as this before making their claims?
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Claim: Human fat quantity and distribution is like that of aquatic mammals; it is adapted for insulation and swimming in an aquatic environment. Humans have subcutaneous fat which is bonded to the skin rather than anchored within the body, unlike non-aquatic mammals.
Fact: Human fat characteristics show no sign of any aquatic adaptation, and are radically different from the aquatic mammals AATers say we resemble. Human fat deposits are anchored to underlying depots, just as those of all mammals are. Human fat deposits are found in the same places, and are anchored the same way, as those of other primates.
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Claim: Seals sweat through eccrine sweat glands, like humans, because aquatic mammals lose their apocrine sweat glands.
Fact: Seals don't sweat via eccrine sweat glands, and in fact the sweat glands of seals are apocrine glands (refs in "skin" link below).
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Claim: Human sebaeceous glands waterproof the skin, like the sebaeceous glands of seals (and that "Sebum is an oily fluid whose only known function in mammals is waterproofing the hair and skin.").
Fact: Sebaeceous glands cannot waterproof human skin (which is why your skin wrinkles when wet). This is because human skin is very different than the skin of seals. And that's not the only evidence that human sebaeceous glands are not an aquatic adaptation. The primary function of sebum, the outpout of the sebaeceous glands, is to produce scent (generally as a sexual attractor). This is true of a variety of mammals, including humans. In some seals, sebum can also keep their highly specialized skin pliable as an aid in waterproofing (refs in "skin" link).
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Claim: Aquatic mammals copulate facing each other, like humans do, while other terrestrial mammals don't.
Fact: This statement is at odds with the facts about mating postures.