Some scientists are not slowed much by the creationist assault on evolution and other science education.
While we’ve been talking here, people like Andrew Ellington are advancing the science with regard to what we know about origin of life and “RNA world” issues. See “Misperceptions meet state of the art in evolution research,” from Ars Technica. For speed’s sake, and accuracy, I’ll quote extensively from John Timmer’s article at Ars Technica.
Four scientists laid out the state of the art in their respective fields in a session sponsored by the American Association for the Advancement of Science’s Dialog on Science, Ethics, and Religion, in late February 2008, at AAAS’s annual meeting. [Where? I don’t know.] Andrew Ellington spoke about origin of life research, Douglas Erwin explained new findings on fossils from the Cambrian, Ted Daeschler detailed the state of knowledge about how fish turned into tetrapods on land, and John Relethford addressed human evolution.
The discussion of life’s origins was handled by Andy Ellington of the University of Texas – Austin. He started by noting that simply defining life is as much of a philosophical question as a biological one. He settled on the following: “a self replicating system capable of Darwinian evolution,” and focused on getting from naturally forming chemicals to that point.
Ellington noted that chemicals necessary for life can and do form without living things. He said research shows that the first replicating chemicals led to the first reproducing life forms. And finally, he said that RNA activities reveal a lot about how the “RNA World” — before DNA — could function and carry on without DNA, which is in all known life forms today.
[More, below the fold]
The Smithsonian Institution’s Douglas Erwin described recent findings on the radiation of life in the Cambrian, suggesting that oxygen and burrowing creatures played roles that were not previously appreciated to be as important as they were.
The first of these was oxygen, which reached unusually high levels in the Cambrian atmosphere. Results published while this article was in preparation reveal that the radiation of animal life closely tracked oxygenation of the ancient ocean. The second was nutrient-rich sediments. Tracks from the first burrowing animals appear in sediments just prior to the Cambrian, and Erwin argues that these animals kept resources in the sediments circulating within the biological community long after they would have otherwise settled out and been buried.
Reading Erwin’s material, I wondered if we couldn’t just video tape his presentation to use whenever a creationist starts to babble about how evolution in the Cambrian somehow cannot be explained by evolution theory, and somehow makes evolution earlier and later impossible. Erwin rather carefully noted that all evidence found so far supports evolution, and is explained by evolution theory.
This Cambrian jellyfish probably shared many genes with the first bilateral animals
Erwin also described animal life that was poised to explode. The prior era was filled with the Ediacaran Fauna, which he described as, “no eyes, no appendages, lots of fronds, and maybe some guts.” But that era also generated fossil embryos that suggest that bilateral animals predated the Cambrian. More telling, however, has been the findings of modern genomics and evo-devo. Genomic studies reveal that many of the genes involved in producing complex animals predate animals themselves, and some of the key regulators of bilateral animal development exist in Cnidarians, which don’t share that body plan. Other work has revealed that genetic networks of regulatory genes that are used in appendage and body plan specification probably predate the origins of either limbs or a body plan.
In short, the genetic tools were in place were in place for millions of years before the Cambrian, but it took the Cambrian’s unique combination of environmental challenges and opportunities to force organisms to deploy them in new adaptive combinations.
Fish get legs
Again, from Timmer’s article:
Ted Daeschler of the Academy of Natural Sciences in Philadelphia reviewed our latest understanding of how those fish wound up on land, with limbs to propel them.
Which is a fish, which is a tetrapod? Trick question—they’re all tetrapods.
Daeschler pointed out that a few decades ago, we had two species that don’t even appear on the diagram here, Eusthenopteron and Icthyostega, and a big gap in between them. Although scientists always want to know more, the gap wasn’t a huge problem for them, as they could recognize subtle features of skeletons that the lobe-finned fish shared with the earliest tetrapods. But it was a problem in terms of public relations, as the public had a hard time tracking these subtleties, allowing opponents of evolution to focus on the gap and declare it unbridgeable.
In the 1980s and 90s, other species, such as Pandericthys and Acanthostega, began to fill this gap. Daeschler indicated that a clear pattern emerged, one that linked the appearance of these species with a specific environment and one that represented a new ecological opportunity. All of the fossils were found on a band that, given the then-current arrangement of the continents, was equatorial. The specific environment, however, was one that hadn’t existed previously: broad, alluvial valleys and flood plains that were transformed in the wake of the origin of trees. The recognition that this environment spurred tetrapod evolution has led directly to the discovery of Gogonasus and, perhaps the most famous transitional species ever, Tiktaalik.
Human origins
The final scientific speaker in the session was John Relethford, an anthropologist in the SUNY system. He had so many big messages that he settled on a top-ten list to present them. The first item was simply that humans have evolved, period. The evidence is so overwhelming that Relethford feels that any remaining argument is simply between two religious perspectives on that fact; science has moved on. Item two was to emphasize that we did not evolve from modern apes. Ape is both a generic and a species term, and biologists need to be careful to use it correctly, because we’re confusing the public by being sloppy.
Meet a few of our many relatives
His third message was that scientists study human origins—the plural part is important. The toolkit that we regard as human, including upright walking, tool use, brain size, etc. all arose at different times, some separated by millions of years. A correlate of this was point four: “humanity’s birth was feet first,” as he put it. Upright walking may date back over six million years, and was definitely present four million years ago. At the time, there were no tools and our ancestors had ape-like teeth and cranial capacity. Relethford suggested we’re still not sure what walking adapted us for, but it clearly kept us going for millions of years before we realized it liberated our forelimbs to manipulate sophisticated tools.
Big brains took their time
That delay might have been due to point five, the fact that cranial capacity increased very slowly and gradually over the course of human evolution. This illustrated Relethford’s idea six: there’s no free lunch. Any adaptation has a cost, and the advantages of expanding brain size were constantly balanced against the selective cost of a big brain’s increased energy use and heat output. There was also more than one way to achieve these balances as, for much of their history, our ancestors were not alone. There were many overlapping homo and australopithecus species in the past, as Relethford noted in point seven, and the question of what constitutes a species is often contentious when it comes to our ancestors.
Relethford’s final points backed out to the big picture of science and humanity in general. Eighth on his list was the contention that we should always expect the unexpected, as new discoveries represent the strength of science, not its weakness. He suggested that if people didn’t like the excited confusion caused by H. florensis, then they probably shouldn’t be paying paleontologists. He also voiced disdain for those who speculate that some form of alien intervention was necessary to produce sophisticated humans or the great works of prehistory. “Our ancestors were not dummies,” he stated as point nine, suggesting that this type of thinking was little more than a generation gap taken to an extreme.
His final point was that the full package of modern human traits took millions of years to evolve, so questions as to where we’re headed are somewhat irrelevant. In the time span we should be concerned with, Relethford suggested, all the relevant evolution will be cultural.
I haven’t seen much about this meeting; especially I’ve not seen any creationist response to it. I’m sure I’m behind the curve on finding it, so any pointers you can give to responses would be fine by me. Comments are wide open.
- Audio of this session is available for download or on CD, here: http://www.aven.com/conf.cfm/cid/1038/pg/2
Millard Fillmore's Bathtub 
If you find an inaccuracy somewhere, please cite it, and cite your counter information. “Chemicals necessary for life can and do form without living things” is one of the best researched, most tested, and solid statements from biochemistry.
It is not I who engages in ambiguous language, nor am I skipping any facts. There are several amino acids that form in the experiments I’ve noted. Mr. Panzer, you may do well to get over to the Astrobiology Magazine site, and see what has been learned about origins of life in these past 200 years.
Try these sites:
http://www.astrobio.net/news/
http://www.astrobiology.com/
http://astrobiology.nasa.gov/
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“chemicals necessary for life can and do form without living things”: the genius of disinformation – using ambiguous language to skip between the facts. No polymerase or anything remotely close forms outside a living cell in nature, nor from scratch in any laboratory so far. There’s some simple amino acids that allegedly survived the heat of entry on meteorites, and apart from that methane, ammonia and carbon dioxide. You think you’re lying in a good cause, but there’s no such thing. You fit into the great deceptions perpetrated by the establishment upon the people, brainwashing us from toddlers, busy replacing Empire Religion with Empire Science, without which they could not hide e.g the incredible gift of distributed clean renewable plant fuels and plastics production like Mr Diesel intended all these years in favour of entirely unecessary centralized toxins. Shame on your gullible greed.
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Thanks for the kind words. Ars is online only, no print, so the italics may be skipped.
The folks that run Ars deserve the complements – they’re the ones who have decided that accuracy and detail matter when it comes to science, and they give us the space we need to (usually) provide them. Part of what validates that decision is the amount of traffic we get, so the more people that make it a regular part of their reading schedule, the happier us writers there will be.
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To John Timmer we owe big thanks, first for the great coverage, second for explaining the molecule model, and third, for pointing to the rest of the coverage.
Science is not covered well by popular media, not for lack of trying, usually, but because when things get technical, copy editors and advertising managers blanche. John Timmer and his colleagues wrote up a lot of important science in easily readable prose. Maybe a lot more of us should spend some time at Ars Technica finding out about it, eh? [Style guide issue: Is Ars Technica a fellow on-line title, or a print title that should be Ars Technica?]
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It’s from part of the article that wasn’t quoted here, which talked about the chemistry that was likely to drive the first self duplicating molecules. Ellington says that recent research suggests an RNA ligase ribozyme – an RNA molecule that can chemically link two other RNA molecules together into a single, longer one – was essential to start self duplication.
The AAAS meeting was huge and very broad in scope; evolution occupied only a small corner of it. You can see all our coverage of the meeting here:
http://arstechnica.com/search.ars?Tag=aaas+boston+2008
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Kenny, I do not know. I just stole the image from Ars Technica. You may want to go browse around there — or send a note to Andy Ellington and ask. His address is in there somewhere (or I can give you one, if you can’t find it — e-mail me if you need it).
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That image looks alot like a big piece of tRNA. Do you know if it is?
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That was quite a read!! Good job mate! Oh and btw that clustermap page is insane! I have not seen so many red dots in my life haha (a bit off topic but shhh)
These evolution things interest me (specifically the human evolution in relation to the last few million years). I wonder how developments are going in terms of finding new fossils. I read about it in textbooks but I do not see any new developments :s. I don’t read journals though as often so that might be a reason..
Anyhow keep up the great work!
pKay.
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