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.

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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.

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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):

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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.

Still more on science vs. faith

February 22, 2009 • 12:58 pm

Colin Blakemore, the renowned British neurobiologist, has a pretty hard-hitting article in today’s Guardian about the irreconcilability of faith and science.

. . . . Science has rampaged over the landscape of divine explanation, provoking denial or surrender from the church. Christian leaders, even the Catholic church, have reluctantly accommodated the discoveries of scientists, with the odd burning at the stake and excommunication along the way.

But I was astounded to discover how topical the issue of Galileo’s trial still is in the Vatican and how resistant many Christians are to scientific ideas that challenge scriptural accounts. More than half of Americans, even a third of Brits, still believe that God created humans in their present form.

The process of Christian accommodation is a bit like the fate of fieldmice confronted by a combine harvester, continuously retreating into the shrinking patch of uncut wheat.  . . . .

. . . . Human beings are supremely social animals. We recognise people and judge their feelings and intentions from their expressions and actions. Our thoughts about ourselves, and the words we use to describe those thoughts, are infused with wishes and wants. We feel that we are the helmsmen of our actions, free to choose, even to sin.

But increasingly, those who study the human brain see our experiences, even of our own intentions, as being an illusory commentary on what our brains have already decided to do.

Perhaps we humans come with a false model of ourselves, which works well as a means of predicting the behaviour of other people – a belief that actions are the result of conscious intentions. Then could the pervasive human belief in supernatural forces and spiritual agents, controlling the physical world, and influencing our moral judgments, be an extension of that false logic, a misconception no more significant than a visual illusion?

I’m dubious about those “why” questions: why are we here? Why do we have a sense of right and wrong? Either they make no sense or they can be recast as the kind of “how” questions that science answers so well.

When we understand how our brains generate religious ideas, and what the Darwinian adaptive value of such brain processes is, what will be left for religion?

Finally, over at Freespace, Timothy Sandefur comments on my article in the New Republic on accommodationism and the reactions by the scientists at Edge.

Don Prothero’s superb book on the fossil record

February 22, 2009 • 9:30 am

In WEIT I mention, in the recommended reading at the end, Donald Prothero’s new book, Evolution: What the Fossils Say and Why It Matters, published by Columbia University Press. Prothero, a professor of geology at Occidental College in California, is a prolific writer, having produced or co-produced 26 books, most of them on paleobiology.

I don’t think that What the Fossils Say has gotten nearly the attention it deserves, so I wanted to give it a shout-out here.  It is simply the best existing book on the evidence for evolution from fossils; there is no competitor. It lays out, for the educated layperson, not only the process of fossilization and the biases it imposes on our knowledge of ancient life, but also discusses systematics, how fossils are used to infer genealogy, and (my favorite part), the evidence.  All the favorite transitional forms are there, in nice detail, and many that are not as well known.  Prothero does not shy away from engaging creationists–he uses the evidence against their wrongheaded claims at every turn.  The writing is superb, the illustrations (many by the great Carl Buell) are a joy.  Everybody with an interest in biology and evolution–whether you be a professional or a layperson–should buy and read this book!  If you have any doubts, check all the positive reviews on Amazon.

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Caturday Felid

February 21, 2009 • 6:52 am

This is Dusty, a bedraggled kitten found by my technician in the alleys of the Pilsen district of Chicago.  Dusty was brought up in the lab, where he loved to sleep in plant pots.  After several months we adopted him out to a nice couple who promptly renamed him (ugh) “Odin.”

Cat fact (from here; I don’t vouch for its truth!):  “Did you know that cats share something in common with only two other species on the planet, the giraffe and the camel? These three beasts are the only ones that when running do not alternate their gait. This means that they run forward with both right feet in one stride, and then both the left feet in the next. All other animals advance with one right and one left, then one left and one right.”
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