'Snowball Earth' Evolution Hypothesis Gains New Momentum (quantamagazine.org) 42
The University of Colorado Boulder's magazine recently wrote:
What happened during the "Snowball Earth" period is perplexing: Just as the planet endured about 100 million years of deep freeze, with a thick layer of ice covering most of Earth and with low levels of atmospheric oxygen, forms of multicellular life emerged. Why? The prevailing scientific view is that such frigid temperatures would slow rather than speed evolution. But fossil records from 720 to 635 million years ago show an evolutionary spurt preceding the development of animals...
Carl Simpson, a macroevolutionary paleobiologist at CU Boulder, has found evidence that cold seawater could have jump-started — rather than suppressed — evolution from single-celled to multicellular life forms.
That evidence is described in Quanta magazine: Simpson proposes an answer linked to a fundamental physical fact: As seawater gets colder, it gets more viscous, and therefore more difficult for very small organisms to navigate. Imagine swimming through honey rather than water... To test the idea, Simpson, a paleobiologist at the University of Colorado, Boulder, and his team conducted an experiment designed to see what a modern single-celled organism does when confronted with higher viscosity... In an enormous, custom-made petri dish, [grad student Andrea] Halling and Simpson created a bull's-eye target of agar gel — their own experimental gauntlet of viscosity. At the center, it was the standard viscosity used for growing these algae in the lab. [Green algae, which swims with a tail-like flagellum.] Moving outward, each concentric ring had higher and higher viscosity, finally reaching a medium with four times the standard level. The scientists placed the algae in the middle, turned on a camera, and left them alone for 30 days — enough time for about 70 generations of algae to live, swim around for nutrients and die...
After 30 days, the algae in the middle were still unicellular. As the scientists put algae from thicker and thicker rings under the microscope, however, they found larger clumps of cells. The very largest were wads of hundreds. But what interested Simpson the most were mobile clusters of four to 16 cells, arranged so that their flagella were all on the outside. These clusters moved around by coordinating the movement of their flagella, the ones at the back of the cluster holding still, the ones at the front wriggling.
"One thing that you learn about small organisms from a physics point of view is that they don't experience the world the same way that we do, as larger-bodied organisms," Simpson says in the university's article. It says that instead unicellular organisms are specifically "affected by the viscosity, or thickness, of sea water," and Simpson adds that "basically, that would trigger the origin of animals, potentially."
Last year Simpson posted a preprint on biorxiv.org. (And he also co-authored an article on "physical constraints during Snowball Earth drive the evolution of multicellularity.")
There's a video showing algae in Simpson's lab clumping together in viscous water. "This observed behavior adds evidence to Simpson's hypothesis that single-celled organisms clumped together to their mutual advantage during the 'Snowball Earth' period," says the video's description, "thus adding momentum to the rise of multicellular organisms." But Simpson says in the university's article, "To actually see it empirically means there's something to this idea."
Simpson and colleagues have now received a $1 million grant to study grains of sand made from calcium carbonate and called ooids, since their diameter "could be a proxy measurement of Earth's temperature for the last 2.5 billion years," according to the university's article. Geologist Lizzy Trower says the research "can tell us something about the chemistry and water temperature in which they formed." And more importantly, "Does the fossil record agree with the predictions we would make based on this theory from this new record of temperature?" Trower and Simpson's work also has potential implications for the human quest to find life elsewhere in the universe, Trower said. If extremely harsh and cold environments can spur evolutionary change, "then that is a really different type of thing to look for in exoplanets (potentially life-sustaining planets in other solar systems), or think about when and where (life) would exist."
Carl Simpson, a macroevolutionary paleobiologist at CU Boulder, has found evidence that cold seawater could have jump-started — rather than suppressed — evolution from single-celled to multicellular life forms.
That evidence is described in Quanta magazine: Simpson proposes an answer linked to a fundamental physical fact: As seawater gets colder, it gets more viscous, and therefore more difficult for very small organisms to navigate. Imagine swimming through honey rather than water... To test the idea, Simpson, a paleobiologist at the University of Colorado, Boulder, and his team conducted an experiment designed to see what a modern single-celled organism does when confronted with higher viscosity... In an enormous, custom-made petri dish, [grad student Andrea] Halling and Simpson created a bull's-eye target of agar gel — their own experimental gauntlet of viscosity. At the center, it was the standard viscosity used for growing these algae in the lab. [Green algae, which swims with a tail-like flagellum.] Moving outward, each concentric ring had higher and higher viscosity, finally reaching a medium with four times the standard level. The scientists placed the algae in the middle, turned on a camera, and left them alone for 30 days — enough time for about 70 generations of algae to live, swim around for nutrients and die...
After 30 days, the algae in the middle were still unicellular. As the scientists put algae from thicker and thicker rings under the microscope, however, they found larger clumps of cells. The very largest were wads of hundreds. But what interested Simpson the most were mobile clusters of four to 16 cells, arranged so that their flagella were all on the outside. These clusters moved around by coordinating the movement of their flagella, the ones at the back of the cluster holding still, the ones at the front wriggling.
"One thing that you learn about small organisms from a physics point of view is that they don't experience the world the same way that we do, as larger-bodied organisms," Simpson says in the university's article. It says that instead unicellular organisms are specifically "affected by the viscosity, or thickness, of sea water," and Simpson adds that "basically, that would trigger the origin of animals, potentially."
Last year Simpson posted a preprint on biorxiv.org. (And he also co-authored an article on "physical constraints during Snowball Earth drive the evolution of multicellularity.")
There's a video showing algae in Simpson's lab clumping together in viscous water. "This observed behavior adds evidence to Simpson's hypothesis that single-celled organisms clumped together to their mutual advantage during the 'Snowball Earth' period," says the video's description, "thus adding momentum to the rise of multicellular organisms." But Simpson says in the university's article, "To actually see it empirically means there's something to this idea."
Simpson and colleagues have now received a $1 million grant to study grains of sand made from calcium carbonate and called ooids, since their diameter "could be a proxy measurement of Earth's temperature for the last 2.5 billion years," according to the university's article. Geologist Lizzy Trower says the research "can tell us something about the chemistry and water temperature in which they formed." And more importantly, "Does the fossil record agree with the predictions we would make based on this theory from this new record of temperature?" Trower and Simpson's work also has potential implications for the human quest to find life elsewhere in the universe, Trower said. If extremely harsh and cold environments can spur evolutionary change, "then that is a really different type of thing to look for in exoplanets (potentially life-sustaining planets in other solar systems), or think about when and where (life) would exist."
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Rather, it's clear you can't be bothered to educate yourself on what the cost of the something was.
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Warm is bad in all situations, and freezing cold is good in all situations. That's exactly what they've been saying, you clever, clever, rabbit.
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First you have to prove gods are real, then prove it is your god, the burden of proof is on you for making the claim
He doesn't have to prove anything. Whether you believe in his god(s) or not is entirely up to you and likely does not affect or impact his belief in any way.
FWIW, I don't believe in his god(s) either. I'm a disinterested third party.
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He doesn't have to prove anything. ,/eM>
He's the one making the claim that some omnipotent being created everything. Yes, they do have to prove that being exists.
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You do if you don't want the baby.
Re:Quit Flogging A Dead Horse. (Score:5, Informative)
This experiment showed 70 generation are enough for the algae to become multicellular, when they started unicellular, following an environmental change. This is an observed fact which you cannot much dispute (you can repeat it yourself if you want). In the jargon such as change is called an "evolution". That's all there is about it. We cannot be sure if there was or wasn't divine intervention behind it, and it does nto matter much as long as the observation is reproducible (if the divine intervention happens consistently when the living conditions of the algae are changed) so as the quote goes, they "had no need of that hypothesis" [ https://en.wikiquote.org/wiki/... [wikiquote.org] ]
Re:Quit Flogging A Dead Horse. (Score:4, Interesting)
What this experiment showed is the potential for multicellular cooperation exists in modern bacteria, and emerges in certain situations. It does not necessarily prove this is how the traits evolved in the first place.
If the researchers can trace the genes responsible for this behavior, delete them, and then repeat the results of their experiment (perhaps requiring extra generations for the mutations to appear and be selected for), then you're one step closer.
You will likely never get to an 'absolute' proof, because rewinding evolution billions of years to re-create early life is impossible. We're going to have to live with educated guesses and experiments like these that show those guesses are credible.
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Just because The Church lied to you in the name of God, Doesn't mean anything about God.
This statement is very true and very poignant. "The Church" is a large group of very fallible humans. They find reason to lie, and also sometimes they just screw up. This is normal behavior for large groups of humans.
That means that the things the church says about God could be wrong. All of them. Every word written in the Bible was put there by human hands, and hence it's all vulnerable to human fallibility. There
Re: Quit Flogging A Dead Horse. (Score:1)
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You do a disservice suggesting otherwise to that person.
Rather than tell them, "Science says you can", you tell him, "There's really no such thing as nothing."
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The laws of physics make clear you cannot get something from nothing without Divine Intervention.
OXYMORON - Hold the oxy.
video mentioned, not linked... (Score:2)
Where's the video?
is it this? https://www.youtube.com/watch?... [youtube.com]
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In the article.
Multicellular? (Score:1)
Pretty sure colonial lifeforms and multicellular lifeforms are different things.
Yeah, I didn't read the paper.
From the summary it's not even clear that this isn't an observation about effects from random clumping (efficient arrangements resulting in success). Are the membranes chemically bonded? Is there intercellular communication? Is this a new phenomenon?
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You should have a look at the paper, it's well written. They say they have been able to produce "motile multicellular individuals" that apparently can do synchronized swimming. They don't claim to have seen "complex multicellularity", just a couple of aspects of it.
https://www.biorxiv.org/conten... [biorxiv.org]
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"colonial lifeforms"
They must have been around before the Declaration of Independence.
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Have you ever seen paintings of the Brits marching around New England back in the day? I'd call that a colonial lifeform, those formations are precisely what you would expect if you put the Brits on the N. American continent and let them do whatever they do.
720 million years? (Score:2)
I was under the impression that Snowball Earth was around 650 M years ago and only lasted 30 M years.
If so then the evolution spirt started well before it got cold.
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I doubt it. It took a long time, and a lot of successive evidence, for it to be accepted in the first place. Since it went against what was once thought to be a paradox - Which said the planet would stay frozen over forever.
There is a lot of evidence for Snowball Earth so it would take a lot to disprove it now.
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It's all rigged I tell ya! After Joe broke world inflation he messed with science data, ate a dog with Obama, and then took a nap.
We could all sit around the fire (Score:2)
and speculate on how life emerged, but we'll never know.
summary - multicellular needs a good advantage (Score:3)
Clearly multicellular organisms today have lots of advantages but for evolution to work every step along the way has to be advantageous. The big debate is what is the earliest advantage.
New material landed? (Score:2)
Seems an obvious alternative explanation, but what if panspermian materials landed near then too (as the cause of the ice age or just a coincidence)? External more complex life arrives, and maybe some horizontal gene transfer happens.
It is an interesting idea though. Microcosms of microbes that get an evolutionary boost from separation and forced slowing of their normally quick/short lives.
Life on ice ocean worlds (Score:1)
This seems to lend support to the notion that the oceans on frozen worlds in the solar system could have evolved or support life.
Interesting (Score:2)
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Frankly I'm surprised that the dominant hypothesis has been that conditions had to be easy/beneficial for multicellular life to come about. Ability to withstand adversity has been a major factor in evolution.
Intelligent life is rare (Score:2)
Things like this make the idea of intelligent alien life seem more and more remote. Even on Earth we needed random and unpredictable events like 100 million years of a snowball Earth to kickstart multicellular life. Then consider all the events that had to happen after that, though further billions of years, until you arrive at human beings. We got stuck in a rut with dinosaurs and needed a meteor to wipe them out in order to keep moving forward.
There are probably billions of worlds out there where life has
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cryochemistry (Score:2)
Some chemical reactions happen faster in ice. Discover magazine had a neat article about this, "Did Life Evolve in Ice?": https://www.discovermagazine.c... [discovermagazine.com]
Simpson, eh? (Score:2)
*steeples fingertips*
Europa cold as heck in upper layers. (Score:1)
That could mean the moon Europa has critters that resemble whale-sized Anomalocaris'.
If not, at least it would make a cool sci-fi flick. Anomalocarises look out of this world. Fun merch.