Month: February 2009

Caturday felid

February 28, 2009 • 7:09 am

by Greg Mayer

Oscar the cat gained fame in 2007 when David Dosa reported in the New England Journal of Medicine that he had “an uncanny ability to predict when residents [of the nursing home where he lives] are about to die.”

Oscar the cat becomes death
Oscar the cat

Dosa continues

Thus far, he has presided over the deaths of more than 25 residents on the third floor of Steere House Nursing and Rehabilitation Center in Providence, Rhode Island. His mere presence at the bedside is viewed by physicians and nursing home staff as an almost absolute indicator of impending death, allowing staff members to adequately notify families. Oscar has also provided companionship to those who would otherwise have died alone. For his work, he is highly regarded by the physicians and staff at Steere House and by the families of the residents whom he serves.

An article in Slate later urged us, wisely in my opinion, to take Dosa’s article, if not Oscar, with a grain of salt. Oscar is shown here with the physicist J. Robert Oppenheimer ‘s famous rendering of a line from the Bhagavad Gita; Oppenheimer may be seen saying it in this video.

Homo footprints from Kenya

February 27, 2009 • 10:00 am

by Greg Mayer

In today’s issue of Science, Matthew Bennett and eleven colleagues from Britain, America, Kenya and South Africa report on the discovery of ancient footprints:

Here, we report hominin footprints in two sedimentary layers dated at 1.51 to 1.53 million years ago (Ma) at Ileret, Kenya, providing the oldest evidence of an essentially modern human–like foot anatomy, … The Ileret prints show that by 1.5 Ma, hominins had evolved an essentially modern human foot function and style of bipedal locomotion.

Although there were no directly associated fossils, the most likely maker of the prints was Homo erectus.  In WEIT, Jerry discussed the famous 3.75 million year old Laetoli, Tanzania footprints, which established that our ancestors had walked bipedally since at least that time.  The Laetoli prints, however were made by Australopithecus afarensis, and the newly announced prints are the oldest known for our genus, Homo (we are Homo sapiens), and Bennett et al. discuss the ways in which the Ileret prints indicate their makers had a more modern foot morphology than the makers of the Laetoli prints.  Homo erectus had a smaller brain than we do, so we see a general pattern in the fossil record exemplified: mosaic evolution–  different characters evolving at different rates.  In this instance, we see an essentially modern foot, with a brain that is intermediate between Australopithecus and modern Homo.  And, we see, once again, that intermediate forms occur at the times, and in the places, we expect them to on the hypothesis of descent with modification.

Update: A reader asks are the new prints from Homo erectus or Homo ergaster, two very closely related fossil species of Homo.  Bennett et al. don’t claim one or the other, writing:

The large stature and mass estimates derived from the Ileret prints compare well with those of Homo ergaster/erectus on the basis of postcranial remains and are significantly larger than postcrania-based stature and mass estimates for Paranthropus boisei and Homo habilis (table S3) (19–21), suggesting that the prints at FwJj14E were made by Homo ergaster/erectus individuals.

In media reports, other scientists, for example Daniel Lieberman of Harvard (quoted in the New York Times), have referred to the prints as from erectus.  My own view is that the species taxonomy of fossil hominids is probably oversplit; if there is to be one name, it would, by priority, be erectus. The great Ernst Mayr wrote a paper in 1951 entitled ‘Taxonomic categories in fossil hominids’ (Cold Spring Harbor Symposia on Quantitative Biology 15:109-118), and it’s worth rereading; see also what Jerry had to say in chapter 8 of WEIT.

More good books

February 26, 2009 • 7:57 am

by Greg Mayer

In an earlier post, Jerry called Janet Browne’s two-volume work the best of Darwin biographies, calling it “magisterial and engagingly written.”  I concur, and some of our readers have mentioned it approvingly in the comments.  But, at 1200 + pages, it may be a bit daunting as a starting place.  Let me offer two other starting places for the Darwin enthusiast.  Charles Darwin, by Tim BerraThe first is Charles Darwin: The Concise Story of an Extraordinary Man, by Tim Berra, an ichthyologist from Ohio State.  In this slim (144 pp.), well illustrated, volume Berra covers most of the highlights of Darwin’s life, work, and death, and includes a handy annotated list of Darwin’s books and chronology of his life.  There is a nice section of color plates (many by Berra himself of the Galapagos and Down House, Darwin’s home), including my favorite, a painting of 32 breeds of domestic pigeon, one of Darwin’s favored study animals. An afternoon’s read, it is a good place to start.

For a broader view of the science of evolution, but, like WEIT, aimed firmly at the general reader, I highly recommend The Discovery of Evolution, The Discovery of Evolution, by David Youngby David Young of the University of Melbourne. Richly illustrated with both color and line art from contemporary scientific publications, and covering a broad sweep of history, from John Ray and Francis Willughby in the 17th century through to the Modern Synthesis, with a quick tour of more recent developments, it is one of the finest books I’ve ever read not just on the history of the field, but on evolutionary biology itself.  It achieves this distinction by introducing and explicating, in chronological sequence, not just the ideas and historical figures, but the evidence on which the major discoveries of evolutionary biology are based.  It is refreshing and, indeed, exciting, to have these discoveries and attendant scientific debates addressed through the evidence adduced by the discoverers and debaters.  Thus, for example, the phenomenon of natural extinction,  which we today take for granted, is presented as the lively debate it was at the time, and we see it is resolved not by some textbook fiat (as too much of science education seems to be), but by careful anatomical, biogeographic, and geological research, with the great Georges Cuvier’s work on elephants, mammoths, and mastodons playing a major part in the resolution.  The entire book is replete with such examples, and is itself an edifying model of how science should be taught and learned: by direct consideration of the evidence.

Sexual parasitism in anglerfish

February 25, 2009 • 3:51 pm

Before I take off, I wanted to highlight one more marvel of evolution: the phenomenon of sexual parasitism in anglerfish.  There are many species of these deep-sea fish, who make their living as predators in the abyssal depths.  Because the population density is low, when a male finds a female his best strategy (apparently) is to fuse his tissues with hers, becoming in effect a permanently parasitic sack of gonads, whose only function is to fertilize the female (no anthropomorphizing, please!).  Sometimes more than one male attaches to a female.  Here are some photos.

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The phantom anglerfish, Haplophryne mollis, with male attached on bottom.

0130anglerfish

Photocorynus spiniceps, an anglerfish from Sumatra. This female is 46 mm long (1.8 inches). Attached to her is a 6.2 mm male (about 0.25 inches), which may be the smallest sexually mature vertebrate known. Below is an enlarged photo of the male.

0130anglerfish2

Meet your guest blogger

February 25, 2009 • 11:55 am

From tomorrow through March 9, I’ll be sailing the Caribbean and lecturing on a Scientific American “Insights” cruise, bound for the islands, Costa Rica, and Panama (tough job, but somebody’s gotta do it). So that you’re not deprived here of matters evolutionary, I’ve asked my friend and colleague Dr. Greg Mayer, an Associate Professor of Biological Sciences at the University of Wisconsin-Parkside, to fill in for me, and he’s kindly agreed. Greg is also Adjunct Curator of Reptiles and Amphibians at the University of Wisconsin Zoological Museum and Field Associate in the Department of Zoology of the Field Museum of Natural History. He did his undergraduate work at the State University of New York at Stony Brook, and received his masters and doctoral degrees in organismic and evolutionary biology from Harvard University. After his graduate work, Greg did postdoctoral research at the Smithsonian Institution’s National Museum of Natural History, and at the University of Wisconsin Zoological Museum. His research and teaching have taken him to many places, including Central America, South America, throughout the West Indies, and to Darwin’s own enchanted isles, the Galapagos.

I have known Greg since he was an undergrad at Stony Brook. He’s not only deeply read in evolutionary biology, but also a tireless opponent of creationism and an excellent writer. I should add that he is co-author of a paper called “The platypus is not a rodent.”

Please welcome Greg and do follow his posts over the next ten days or so. Here he is in Costa Rica collecting reptiles (blue bag at his waist):

greg-mayer

WEIT reviewed in The Bookbag

February 25, 2009 • 8:42 am

The Bookbag is a newish but (I think) fairly popular book-review site in the UK. It just reviewed WEIT and (to my delight) gave it a great review and five stars out of five. An excerpt:

The main gist is in fact remarkably similar (if very much developed in detail) to the evidence of evolution I learned at school twenty-five years ago. What makes Why Evolution Is True an instant classic is Jerry Coyne’s supremely lucid, graceful presentation and the fluency of argument informed by the variety of sources form Darwin himself to the cutting edge of modern research.

Coyne’s delivery is elegant but by no means a dry lecture: passionate and erudite, he maintains just the right balance between academic and accessible. He never talks down to his readers, but explains clearly pretty much anything that goes beyond the very basics of biology. . ..

This book should not be needed, and yet it seems necessary. It will not persuade the hard-line creationists, because creationism, as Coyne repeatedly (and rightly) states, is a matter of belief, not science. For those who are uncertain, or for whom the support of evolution theory is more a question of general ‘it makes sense’ acceptance, for those looking for arguments to enlighten the unconvinced and argue with the opposition, Jerry Coyne’s book is indispensable.

I get to brag here because it’s my blog!

Forbes loses it again over evolution

February 24, 2009 • 2:01 pm

A few days ago I wrote a piece for Forbes online responding to the ignorant assertions of a physician, Dr. Michael Egnor, who maintained that there was no evidence for Darwinian evolution.  In response, I reiterated the tenets of Darwinism and then cited copious evidence, through links in my piece, for common ancestry, transitional forms, vestigial organs, and the origin of new, complex biochemical systems through natural selection.  I also took Forbes itself to task for soliciting the opinions of intelligent-design creationists such as Egnor to “balance” their coverage of the Darwin bicentennial.  To its credit, Forbes allowed me to publish pretty strong criticism of their “let’s give crackpots an equal say” policy.

Well, I take the credit back.  Forbes has now given yet another benighted individual the final say in the debate.   Meet Dr. Philip S. Skell and his anti-Darwinian views.  Skell, an emeritus professor of chemistry at Penn State University, has been retailing his creationism and, especially, his disdain for evolution for some time on the Web (see, for example, here or here).

The curious thing is that Skell’s piece is not, as it pretends to be, a critique of what I said in Forbes, but merely a repetition of the argument, which he has been making for years, that evolution is of no practical use for humanity and of no use to experimental biology:

I don’t think science has anything to fear from a free exchange of ideas between thoughtful proponents of different views. Moreover, there are a number of us in the scientific community who, while we appreciate Darwin’s contributions, think that the rhetorical approach of scientists such as Coyne unnecessarily polarizes public discussions and­–even more seriously­–overstates both the evidence for Darwin’s theory of historical biology and the benefits of Darwin’s theory to the actual practice of experimental science.

He demeans fossils, for example, as having no bearing on helping us understand how organisms function:

Experimental biology has dramatically increased our understanding of the intricate workings within living organisms that account for their survival, showing how they continue to function despite the myriad assaults on them from their environments. These advances in knowledge are attributable to the development of new methodologies and instruments, unimaginable in the preceding centuries, applied to the investigation of living organisms. Crucial to all fruitful experiments in biology is their design, for which Darwin’s and Wallace’s principles apparently provide no guidance.

Contrary to the beliefs of Professor Coyne and some other defenders of Darwin, these advances are not due to studies of an organism’s ancestors that are recovered from fossil deposits. Those rare artifacts–which have been preserved as fossils–are impressions in stones which, even when examined with the heroic efforts of paleontologists, cannot reveal the details that made these amazing living organisms function.

What?  What about the evidence that feathers arose as thermoregulatory devices, and possibly as sexual signals as well? What about the evidence that some dinosaurs were warm-blooded, or that human ancestors were bipedal before they evolved big brains?  What about the “details” of the fish-amphibian transitional form Tiktaalik that show how it was adapted to functioning in the water and, fortuitously, evolved traits that were to help it invade the land?

Skell goes on and on about how “experimental” science actually helps us understand stuff, while historical sciences like evolutionary biology are useless:

It is widely accepted that the growth of science and technology in the West, which accounts for the remarkable advances we enjoy today in medicine, agriculture, travel, communications, etc., coincided with the separation, several centuries ago, of the experimental sciences from the dominance of the other important fields of philosophy, metaphysics, theology and history.

Yet many popularizers of Darwin’s theory now claim that without the study of ancient biological history, our students will not be prepared to engage in the great variety of modern experimental activities expected of them. The public should view with profound alarm this unnecessary and misguided reintroduction of speculative historical, philosophical and religious ideas into the realms of experimental science.

Skell cannot help himself.  In his endless feedback loop, he says the same things over and over again–the same things he’s been saying for years:

The essence of the theory of evolution is the hypothesis that historical diversity is the consequence of natural selection acting on variations. Regardless of the verity it holds for explaining biohistory, it offers no help to the experimenter–who is concerned, for example, with the goal of finding or synthesizing a new antibiotic, or how it can disable a disease-producing organism, what dosages are required and which individuals will not tolerate it. Studying biohistory is, at best, an entertaining distraction from the goals of a working biologist.

Yes, Dr. Skell, the practical advantages of evolutionary biology, while real, are limited.  I myself have made this  point in a book review in Nature.  But does the only value of science lie in its ability to make us rich or cure our diseases?  Many of us disagree.  Is it useless to know about The Big Bang?  Or about how we evolved from our primate ancestors?  Science is a process of finding out things–of satisfying our curiosity about nature, and understanding where we came from.  Some of that has practical benefits, some has spiritual benefits, but all of it is useful.  I would hardly call pure research “an entertaining distraction from the goals of a working biologist,” unless Skell’s definition of a working biologist is “one who cures diseases” (which, by the way, would put Dr. Skell in the not-a-working-biologist class, since his accomplishments are in carbene chemistry).  Evolution is the best story in science–it tells us where we came from, and by “we” I mean all living species, not just humans.  And it is a true story, and a wonderful one.  Unravelling and telling that tale is not “an entertaining distraction,” but part of what it is to be human.

Finally, Skell makes a mistake that brands him indelibly as a tyro in evolution:

It is unseemly and scientifically unfruitful that a major focus in biology should have turned into a war–between those who hold that the history of those unique organisms is purely a matter of chance aggregation from the inorganic world and those who hold that the aggregation must have been designed for a purpose.

The last time I looked, evolution was far more than a process involving “chance aggregation from the inorganic world.”  It critically involved a non-chance process: natural selection.  And are we to blame evolutionists for the intelligent-design movement, as Skell seems to do? That is palpable nonsense.

What is more distressing than Skell’s nonsense, which after all he’s been spouting for years, is the fact that Forbes has given him the last word in this debate.  And not only that, but a word that fails to respond to anything I have said. What is going on over there?  If they’re going to solicit a creationist to respond to me, presumably they would want one who could address my substantive points, including the many links I gave for the evidence for evolution. I said absolutely nothing about the usefulness of evolution to the material welfare of humans.  I did write the Forbes editor (who alerted me to Skell’s post) asking why it was published, and received no reply.   Apparently we can write off Forbes as a voice for reason.