Recently in Transitional Fossils Category

Anne Minard of National Geographic News writes on July 9^th

The discovery of a missing link in the evolution of bizarre flatfishes—each of which has both eyes on the same side of its head—could give intelligent design advocates a sinking feeling.

CT scans of 50-million-year-old fossils have revealed an intermediate species between primitive flatfishes (with eyes on both sides of their heads) and the modern, lopsided versions, which include sole, flounder, and halibut.

So the change happened gradually, in a way consistent with evolution via natural selection—not suddenly, as researchers once had little choice but to believe, the authors of the new study say. … Though known for their odd eye arrangement, no flatfish start life that way. Each is born symmetrical, with one eye on each side of its skull.

As a flatfish develops from a larva to a juvenile, one eye migrates up and over the top of the head, coming to rest in its adult position on the opposite side of the skull. … Palmer added that the new work is “a fantastic paper” that helps resolve a mystery “that’s bedeviled evolutionary biologists for more than a century.

“It’s really been a major, major puzzle to evolutionary biologists.”

As expected, the Magisterium of Intelligent Design was quick to condemn the finding as simply floundering around, while the Institute of Creation Research has a turbot-charged attack on the finding, pointing out that flatfish are sole-ly members of the flatfish ‘kind,’ and putting National Geographic in it’s plaice.

Neil Shubin’s latest book on evolutionary theory is by all standards a great success. It ranks around 200 in Amazon books and first in Evolution Science Books. When I checked the book’s availability in our library system there were close to 40 pending holds.

A sales rank of 200 means 225-250 books per week are sold. Compare this to a rank of 24,000 for Behe’s boo “Edge of Evolution” sold at a bargain price of $6.99 down from $28.00 or 111,550 for the regular priced version. Those numbers translate to few copies per month being sold.

Neil Shubin is a professor of organismal biology at the University of Chicago. He, as part of a team of scientists, discovered the now infamous Titaalik transitional fossil which causes so much consternation amongst Intelligent Design Creationists. His book Your Inner Fish introduces its readers to an exciting overview of how our evolutionary history links us back to a common ancestor with fish. Of course, that’s not where our common ancestry ends.

Why do we look the way we do? What does the human hand have in common with the wing of a fly? Are breasts, sweat glands, and scales connected in some way? To better understand the inner workings of our bodies and to trace the origins of many of today’s most common diseases, we have to turn to unexpected sources: worms, flies, and even fish.

In Your Inner Fish, Neil Shubin tells the story of evolution by tracing the organs of the human body back millions of years, long before the first creatures walked the earth. By examining fossils and DNA, Shubin shows us that our hands actually resemble fish fins, our head is organized like that of a long-extinct jawless fish, and major parts of our genome look and function like those of worms and bacteria.

Although many have read the transcripts of the Kitzmiller v. Dover trial (HTML version | PDF version) and found them interesting, reading the transcripts does not give the full sense of what it was like to be in the Kitzmiller courtroom. In real life, in addition to the witness answering questions, the lawyers and witnesses were constantly referring to exhibits that were digitally projected onto a large screen on the right wall of the courtroom. Usually the exhibits were just documents, but when the science witnesses testified, their powerpoint presentations contain fossils, flagella, and everything else in between. I think it is safe to say that the testimony is much easier to understand when read with the demonstrative exhibits available (the exhibit lists and a few exhibits are available online).

However, it takes a lot of work to convert the slides to web format, add captions, embed them in HTML, etc. But as a first step, I and others at NCSE have done this for Kevin Padian’s testimony (testimony+slides | just slides).

I missed this one a week or two ago. Simon Conway Morris and his colleague Jean-Bernard Caron published a paper in Science on a new Cambrian fossil called Orthrozanclus. The cool thing about the fossil is that it combines features from two other fossils that Conway Morris previously implicated as transitional stem groups between the modern crown groups (“phyla”) of mollusks, annelids, and brachiopods: Wiwaxia and Halkeria. Of course, according to Discovery Institute propaganda, transitional fossils like this don’t exist.

Here is a news summary. See also the Orthrozanclus post from PZ Myers, his post last year on another stem group mollusk-ish critter, Odontogriphus.

Several people have suggested that I factor out body size to produce a chart just showing the relative increase in brain size over time. This is not as simple to do as it sounds, because most of the fossil skulls are not found with bodies, and vice versa [1]. So even if I had the paper with the body size data (De Miguel and Henneberg (1999). “Variation in hominid body size estimates: Do we know how big our ancestors were?” Perspectives in Human Biology, 4(1), pp. 65-80), one could not just do a regression. So we have to improvise.

Due to popular demand I have made some more charts that are slightly more complex than the hominin cranial capacity chart from yesterday’s post.

In the first chart, I have taken the “favored” taxonomic labels for each specimen from De Miguel and Henneberg (2001). Many specimens have been put in different species or different genera by different taxonomists, but these are supposed to represent something like the consensus, as the authors judged it in 2000. Australopithecus fossils are in red with various symbols, early Homo fossils (Homo habilis and others just labeled “early Homo” or “Homo”) are in orange, H. erectus is in green, and the asundry variations on Homo sapiens are in blue.

For some time I have been annoyed that charts of the changing cranial capacity of fossil hominin skulls are not more common. There is this chart online at the Talk.Origins Fossil Hominids FAQ, derived from this 1994 PNAS paper, but that is about it. I wanted to make my own chart, but there was no easy way to get all of the relevant data. Then, this week, I ran into this amazing paper (De Miguel and M. Henneberg 2001*), which conviently included a 29-page Appendix listing every known published measurement of a hominin skull older than 10,000 years old.

While killing my brain cells by listening to the radio broadcast of the ID movement presenting cutting-edge research in the USF Sun Dome conducting an old-fashioned creationist revival in the USF Sun Dome,** I schlepped all 602 measurements and metadata into Excel.

One of the more hilarious absurdities of the creation/evolution debate is as follows: creationists love to hop up and down and point at gaps in the fossil record (sometimes real, often not), but for the one species that creationists would dearly love to be specially created, human beings, we are actually swimming in a stunning set of transitional fossils. The hominid fossil record isn’t even especially “jerky” when examined quantitatvely at fine-scale resolution, so the creationists don’t even have their usual incompetent misconstrual of punctuated equilibria (which is actually about morphologically small gaps between closely-related sister species) to rely upon.

The poor creationists can’t even agree on which fossils are human and which are ape, and even Casey Luskin of the Discovery Institute has tried his hand at this (proving he is a creationist, by the way), arguing that the genus Homo is a specially created “basic type”, except for the inconveniently transitional Homo habilis, which he removes from the genus by creative citation, thus proving that there is a gap between Homo and other hominins! Because of course everyone knows if you switch the label on a fossil, it’s transitional features disappear and it can be safely ignored! (If you are counting, Luskin’s position appears to be closest to that of the creationists in the middle column, including Gish and others, which appears to be the median creationist position.)

As if designed to ruin Luskin’s weekend, Nature has just published yet more hard fossil evidence of human evolution: