Did Sea Life Arise Twice? 238
eldavojohn writes "Dr. Adam Maloof has found fossils of sea sponges in Australia from 650 million years ago. You might think this is no big deal unless you consider that sea sponges were thought to have arisen 520 million years ago. These fossils predate the oldest hard bodied fossils we have by a hundred million years. Dr. Maloof is now wondering if life might have arisen twice after the first attempt was quashed 635 million years ago: 'Since animals probably did not evolve twice, we are suddenly confronted with the question of how some relative of these reef-dwelling animals survived the Snowball Earth.' So how is it that life survived the Marinoan glaciation? The BBC has a video on the topic and Wikipedia has a time line of the Proterozoic Eon into the Paleozoic Era."
Re:The missing link (Score:2, Insightful)
I... Get oversights and mistakes - and yes this be one - clearly the good doctor wants his work to get popular enough to go under enough scrutiny to find the mistakes.
However - I don't see what any of this has to do with God.
Re:Throw away the Snowball. (Score:1, Insightful)
More likely, this is evidence that there never was a Snowball Earth. We've never been sure whether the entire Earth froze up or just large areas of it. If creatures lived through the glaciation, that's a good indication that unfrozen regions still existed.
The other option is that there were areas where geothermal heat kept it from freezing. Early animal life may have even been based on geothermal heat. Sponges are pretty simple organisms and might have evolved like extremophile bacteria.
Re:Life (Score:3, Insightful)
*At least* once... (Score:5, Insightful)
I then point out to them that *all* we know is that life has been created on this planet *at least* once. It may have happened a million times, for all we know. Out in that vast ocean, there are countless chances for it to happen every day and it very well *may* be happening. Who the hell knows? Any life that we may find out there in the oceans gets attributed to being descended from the *first* occurrence of life... but that might not really be the case.
So, this notion that life may have arisen twice? I don't find it shocking at all. Okay, I guess I'm a little piqued by the fact that researchers think that they hold *evidence* of it (since that's a little harder to do) but, like I said, I have a hunch this has happened millions of times since the "first time".
Re:Life fills a space defined by its environment (Score:5, Insightful)
But scientists can usually tell different species. They may look superficially identical, but they have unique organs which indicate if it's the same species, or a different species that discovered the same niche.
I think the likely explanation here is that (1) it's the same species at ~500 and ~600 million years ago, and it did survive the extinction because (2) Snowball earth wasn't as harsh as we believe.... there were probably warm zones around the equator for a few sponges to hang-on.
Re:Throw away the Snowball. (Score:5, Insightful)
Yes. This. There is a certain amount of cognitive dissonance to be expected when a presumably scientific article is surrounded by such journalistic gems as "Brittany Murphy's mother 'shared bed with daughter's husband after her death'.
One's head asplodes, it does.
Re:Life fills a space defined by its environment (Score:5, Insightful)
Re:*At least* once... (Score:3, Insightful)
One of the strangest Cr. arguments is that life never evolved from scratch in a sealed peanut butter jar. Despite being silly, it got me thinking: what would happen if it did? The person who discovered it would probably just toss it in the trash and nobody would ever know. It's not like everyone runs to the local science lab every time they find gray slime in a food product. Defective packaging is not uncommon.
If released, the "first batch" would probably be non-competitive with existing life anyhow such that present-day microbes would likely overtake it, hiding any clues that it would be new or different. Remember, the first batch of Earth life didn't have to be competitive, and thus could easily lack a lot of the fancier mechanisms and be quite simple. As the Precambrian Bill Gates once said, 640 molecules otta be enough for anyone.
Re:Throw away the Snowball. (Score:5, Insightful)
According to the linked Wikipedia article, even the dating of the 'Cryogenian' period is pretty loose. People need to look at those solid lines separating geologic eras with a grain of salt or at least a Photoshop^HGimp gradient. It's not like God came down and said "OK it's now Cambrian time, lets pop out those hominids riding dinosaurs, and while your at it, lets change the color of the strata to mauve."
Right?
Re:Life fills a space defined by its environment (Score:3, Insightful)
Hey, they should add that as one of the loglines they use up top.
Slashdot: News for nerds. Stuff that matters.
Slashdot: It is what IT is.
Slashdot: TFA is interesting, TFS is garbage.
Re:Life fills a space defined by its environment (Score:2, Insightful)
There is no proof at all that life exists anywhere else except on earth. When and if we find life elsewhere, than we can make conjecture about panspermia, until then it's just science fiction. Not even junk science.
The fact that life exists on Earth indicates that it most likely exists elsewhere, since the probability of life isn't equal to zero, and there are a ridiculous number of stars and planets.
Basically, the burden of proof is on you to say that life exists only on Earth. That scenario is so unlikely as to not even be funny.
Re:*At least* once... (Score:3, Insightful)
I have a hunch this has happened millions of times since the "first time".
That was my reaction as well. "Why only twice?" If the conditions existed for amino acids to develop and combine, the odds of cellular and multi-cellular life occurring only once would have to be very small indeed. It's a huge planet at the microbial level. Heck, life probably came to be over and over and over again, regardless of whether another pond a kilometer away was having the same thing occur in it.
I think you're being a little hard on the guy (Score:5, Insightful)
Ok, it seems there are two possibilities here: it could be that being "confronted by the question of how they survived" is a rhetorical device leading up to just such a hypothesis, even if they didn't publish it in the article. Or maybe you're just a lot smarter than the "idiot" (who's a paleontology PhD) quoted here. Which do you think is more likely?
Re:Life fills a space defined by its environment (Score:3, Insightful)
That's 1 cut above "given money, trees and an infinite universe, somewhere money does grown on trees"
No because life does exist here. Money doesn't grow on trees.
If money did grow on trees here, then given money, trees, and an infinite universe, its probable that money grows on trees somewhere else too.
Re:Life fills a space defined by its environment (Score:3, Insightful)
Give it some Heisenberg treatment. We cannot determine if life exists elsewhere, therefore for the purposes of meaningful scientific debate we have to act as if both possible realities are true. Anyone involved in that kind of discussion has to be equally ready for both possible outcomes.
We can't look to life on Earth as proof for or against life elsewhere.
Re:We all know about the scientific method. (Score:3, Insightful)
I was not born yesterday.
I am a believer of Last Thursdayism you insensitive clod.
There is nothing contradict the theory that the entire universe was created Last Thursday. With all the people with memories of events happening before Last Thursday, with memories of ancestors, the heirlooms, etc etc, every thing was created Last Thursday. With stars billions of light years away too, with light stretching all the way back to these stars from Earth, with fossils already buried in strata of rock, and with radio active elements already decayed.
Remember if the Theory of Evolution in invalidated, Creationism does not automatically win. It has to duke it out with Last Thursdayism, The Celestial Teapot, The invisible pink unicorn theory and the Flying Spaghetti Monster Himself.
Re:*At least* once... (Score:3, Insightful)
Agreed. Life arising, dying out completely, and arising again I could buy - if the earth went through conditions sufficient to sterilize everything.
Life starting 50X in parallel seems hard to fathom, when half the reason we're so sure that everything evolved is all the homologies. Where are all these creatures that aren't descended from a common ancestor? It should be completely evident in their biochemistry.
Re:Evolution finally refuted (Score:4, Insightful)
Accurate smakurate! What we really need is a dating method that won't be rejected by anti-science types. Unfortunately, we all know that is impossible, because their objections are ideological, not scientific. So, we are left with only one option, which is to ignore the anti-science types.
Re:Dating methods are accurate! (Score:2, Insightful)
How wildly different? In science we almost never get the same answer; instead we get a statistical gradient (yet science still works!). I'm prepared to assume +/- 3% is a reasonable error for accuracy in some experiments, while you might require +/- 0.1%. Or an experimenter might draw false conclusions from the data, or the error might be so large as to invalidate the correlation he or she draws, or the method might be entirely discredited. Either way, the results are rarely glaringly obvious (otherwise we wouldn’t need rigorous peer-reviewing processes) and you must qualify your criticism for it to be anything but speculation.