Wednesday, February 25, 2009

New Discoveries Pertaining to the Evolution of Sex

What do we know about the evolution of sex? Specifically, what do we know about the process of internal fertilisation of eggs by sperm?

Information relevant to these key questions have been documented in a new discovery that was recently reported in the journal Nature and discussed in an online article by the BBC.

The discovery actually happened in the laboratory when a group of scientists at London's Natural History Museum began investigating Placoderms, a group of fish dating from the Devonian ("the age of Fishes), that were characterised by a strong external armour-like covering. One particular specimen, dating to approximately 365 mya (million years ago), shows particularly striking and direct evidence for internal reproduction. A small embryo, 5 cm in length, was found inside this particular fossil. Internal fertilisation is also suggested among the Placoderms, in general, by evolutionary changes to the pelvic fin which forms a structure known as a clasper. The anatomical modification provided a means for male and female fish to connect - so to speak - during mating.

The Placoderms were among the earliest jawed vertebrates. thus occupying a place in our evolutionary heritage near the origins of vertebrates. Placoderms - like most species, both ancient and modern - became extinct. They were suceeded by a group of bony fishes that ultimately evolved into the tetrapods - animals with a four-limb pattern that include birds, mammals, reptiles and amphibians.

I'll have more to say about the evolution of animals and plants in upcoming posts on variation and intermediate forms.

Thanks to Graeme Wright for information about the findings pertaining to Placoderms.

Sunday, February 22, 2009

Announcing: Classic and Contemporary Readings in Physical Anthropology

I'm happy to announce a new book of readings in physical anthropology which I edited with Dr. Eileen Jackson. We selected readings that reflect important articles in the history of physical anthropology as well as more recent offerings that highlight new discoveries and innovative methodologies. We include the vision of physical anthropology as originally seen by its founder, Ales Hrdlicka, as well as a groundbreaking article by Sherwood Washburn on the new physical anthropology. Key articles on evolutionary theory, primates, human genetics and contemporary human variation are included. Discussion questions follow each chapter along with key terms and recommended web sites. Publication information is presented below along with a link to the publisher's website.

Classic and Contemporary Readings in Physical Anthropology, 1st Edition
Mary K. Sandford
ISBN-10: 0495510149 ISBN-13: 9780495510147
160 Pages Paperbound
© 2009 Published

Thursday, February 19, 2009

In the News: Updates on Blog for Darwin

Bloggers from around the world participated in the "Blog Slam" program, "Blogging for Darwin," in honor of the 200th birthday of Charles Robert Darwin, the man who is arguably the single most influential life scientist ever. One hundred sixty five bloggers from such diverse locations as Turkey, the Galapagos Islands, and the United States posted writings from 12th February to the 15th February. These blogs will be archived by subject and available as permanent resources for students and teachers. The two blogs I wrote as part of this endeavor were published on the front page of the "Blog for Darwin" site. You can explore "Blog for Darwin" using the following address:

Saturday, February 14, 2009

Advice to a Young (or Old) Scholar: Reading Darwin, Part 1

Now that I’ve made the challenge to actually read On the Origin of Species by the 24th November 2009 (the anniversary of the book’s First Edition), I want to offer some advice that will probably make your experience with this incredible work more enjoyable. If there’s a Cliff Notes (or something like and similar) for On the Origin of Species, I couldn’t find it back in ’76 when I was taking Dr. Greene’s seminar on Evolutionary Theory. Fortunately, there are many resources that will make your experience with this book more enjoyable and enlightening – you’ll be making something akin to your own Cliff Notes as you go. And while you don’t have to assemble a scale model of the Beagle or explore your backyard with a bug box, there are a number of ways that you can prepare your brain for experiencing this masterpiece of scientific elegance.

Whenever we read historical works – whether they’re scientific tomes or novels – learning something about the context is crucial to our understanding. It’s a point that’s often (and unfortunately), lost particularly by those who wish to play “gotcha” with the lives of scientists from times past. So, before you lose yourself in On the Origin of Species, find out more about the person and times of Charles Darwin. And he had a fascinating life indeed. As a boy, he was a passionate collector – of practically anything – and, as an adult at Down House, he cared for his children, juggled several books and projects at a time, and struggled with disabling chronic illnesses.

What we’re really after here is a contextual overview of Darwin’s life before delving into the specificity of his work. Scientific investigations aren’t acts of special creation. Darwin’s life and science were born out of the intellectual and social milieu of 19th century, and influenced by his predecessors, teachers and colleagues. What were the intellectual and scientific foundations for his work? Who influenced him, and how?

If all this sounds like you’ll need (minimally) a new set of Encyclopedia Britannica just to get started, you’ll be pleasantly surprised to learn that you won’t need anything beyond a computer with internet access. A great place to launch your study of Origin of Species is at Down House, itself, home to Charles and Emma Darwin and their children. It was here in his study where he wrote by the fire in his favorite chair and peered through his microscope at slides of stems and seeds. Fortunately, we can take a virtual tour of Down House with David Attenborough as our guide by exploring the estate’s website at .

For learning about the person of Charles Darwin we have virtual access to his autobiography, a work that was edited and includes supplementary material by Francis Darwin, his son. elder Darwin never intended to publish his autobiography – he wrote this rich collection of stories solely for his children and future generations. The work is a gift to all who want a better appreciation for his life and an excellent prelude to your explorations of Darwin’s scientific work.

Thursday, February 12, 2009

A New Challenge: Reading for Darwin

Have you actually read Charles Robert Darwin’s book, On the Origin of Species? That’s both a question and a challenge that I’m posing to you today on the occasion of his 200th birthday. If you have not, I want you to consider – as you ponder the meaning of his life and work – reading (or re-reading) his magnum opus. If you have studied the volume, perhaps you might want to pick it up again; I would be quite surprised if you aren’t filled with a sense of awe when you contemplate Darwin’s actual words.

If you aren’t familiar with it, what you might immediately observe about Origin of Species is the sheer vastness of this work. The book is a comprehensive synthesis of Darwin’s knowledge, as well as his own experiments and observations, from his beginnings as a naturalist to his maturation as a scientist. But its significance is not in its sheer volume. Rather, the vastness of his work reflects his breadth and meticulousness as a scientist and, more important, the magnitude of evidence he used 1) to demonstrate that biological evolution is a scientific fact and 2) to formulate his argument for evolution by means of the mechanism he named natural selection.

These points may seem rather mundane in light of other recent articles and blogs circulating around the virtual world in Darwin’s anniversary year. Yet I feel compelled to review some very basic information about Darwin and to stress the importance – now more than ever – of reading primary sources and understanding them in their historical contexts. It’s easier than ever to access the body of Darwin’s work. Thanks to some very dedicated scholars, digital technology and the information highway, you can read the complete works of Charles Darwin – a virtual library – online at It’s even possible at this marvelous site to see drawings of specimens that Darwin collected during the voyage of the Beagle, to read his natural history treatises and other important books, and to pour over every single page up through the 6th edition of his most famous – and one of the most groundbreaking – books in human history.

Charles Darwin’s work – and the results thereof – has been a guiding force in my life since I was a little girl. I remember the first time I heard his name – a memory that occupies the same compartment of my brain as those that recall picking up fossilized corals and shells while roaming fields near my home in Arkansas and seeing my first dinosaur skeletons extending up toward the high ceilings of the Denver Museum of Natural History. My parents have always been voracious readers and one of their greatest gifts to me was the love of learning – through books, museums and even the fields beneath our feet. Early in my childhood, my mother, a sociologist, followed her fascination with humankind into the discipline of anthropology where she discovered physical anthropology, or the scientific study of human evolution and variation. A few years later (circa 1964), she introduced a handful of college students to topics like natural selection, fossil evidence for human evolution, and biological variation. Meanwhile, both of my parents helped to fend off the less informed; the latter included at least one biology teacher who was convinced that men had one less rib than women and those who leaned on me to make a false choice between “the Bible” or “Darwin.”

So, today, in honoring Charles Darwin, I also want to honor those individuals who introduced me to his work and modeled for me an understanding of its relevance for our lives today on this tiny planet. My parents showed incredible courage in navigating the often circuitous and confusing course required by the life of the mind. Mom taught evolution before it actually became legal to do so in the state of Arkansas in 1968. I would’ve otherwise been denied the opportunity to learn about Charles Darwin and natural selection until I reached college (1971).

Ultimately physical anthropology became my academic home where I taught for close to twenty-five years before my recent retirement. Several semesters into graduate school at the University of Colorado, I took a seminar in Evolutionary Theory taught by Professor David L. Green. It was there – around a long seminar table, worn with age – that I first experienced the true excitement about biological change over time as we read and discussed Origin of Species in its entirety, along with works by Thomas Henry Huxley, Teilhard de Chardin, Ernest Mayr, George Gaylord Simpson, and Jacques Monod (among others). As can be inferred from my presence here today, physical anthropology remains my passion. Link by link, my education as a physical anthropologist was forged; Professor Dennis Van Gerven helped me learn to recognize and interpret variation in ancient, prehistoric and modern skeletons and Dr. Alice M. Brues – a key founder of physical anthropology – took me right to the historical roots of physical anthropology – through gross anatomy and natural history. Most important, she led my friends and me into the foothills surrounding Boulder where she taught us to view the world around us – the birds, wildflowers, trees and, even, the mountains themselves – through the eyes of a naturalist with whom Darwin himself would’ve felt completely at home. It was altogether fitting, then, when Dr. Brues was named recipient of the inaugural Charles R. Darwin award by the American Association of Physical Anthropologists. I thank these people – and I thank my former students and colleagues, who continue to challenge and teach me with their questions, discoveries and perspectives – as I remember the life and work of Charles Darwin today.

Thus, I challenge us all – in a world where knowledge and understanding of science is absolutely essential for our continued life on this planet – to read and continue to talk about Charles Darwin’s greatest contribution to science by November 24, 2009, the 150rh anniversary of publication of Origin of Species.

Let the learning begin and the conversation never cease!

Monday, February 9, 2009

The Economy: It's Science, Stupid!

A saying made famous in the War Room of President Clinton’s 1992 campaign was the oft-quoted “It’s the Economy, Stupid!” It’s not entirely clear who first coined the phrase – I’ve heard both James Carville and Secretary of State Hillary Clinton mentioned as possible authors – but there’s no doubt of its inherent wisdom. It’s as true today as it was in 1992 and given the rate at which our economy continues to worsen it ought to become a mantra repeated dutifully by every member of our society who has any possible contribution to make to economic recovery.

In all the recent talk about the economy – in all the Senate debates, press conference, Sunday news shows – it has become equally clear that Democrats and Republicans – at least with respect to the current economic crisis – are divided along the lines of evidence-based versus ideology-driven policy. President Obama promised during the campaign and his inaugural address to restore science to its rightful place. Without scientific evidence and critical thinking we will see further deterioration of this society and our ability to positively impact the rest of the world. Ideology-driven policies are subject to biases, prejudices, exclusion and raw emotions, like fear.

The wide ranging effects of ideology-driven policy in this country have never been more apparent than in the monumental clean up necessitated by eight years of presidential malpractice at the hands of George W. Bush and Dick Cheney. Right now, in the face of evidence that 1) an economic stimulus package is absolutely essential to turn the tide of the economic downturn and 2) spending is an inherent part of stimulus, Republicans continue to argue for government to keep its hands free of intervening in the economic wows. If anything, Republicans want tax cuts – particularly for corporations and business people at the upper income levels – a practice that helped to catapult this country into the precarious situation at present. Indeed a test vote in the Senate today got the votes that will be needed to pass a stimulus package but only three Republicans had the moral courage to cross the proverbial aisle and join in support with their Demographic colleagues.

When Obama says “I won’t return to the failed theories of the past eight years.” he is implying that his administration’s approach to macroeconomics is based on empirical data. We have, in other words, scientific evidence – reliable data – that a spending approach/stimulus package will promote economic recovery. Harvard economist and Nobel laureate Paul Krugman has discussed the importance of economic stimulus for weeks now. Indeed his most recent column in the New York Times expresses his fear that the stimulus – now delayed by Republicans and perhaps watered down in ill-considered attempts at compromise – will be too little, too late.

The economic system, together with its inexorable ties to subsistence practices and the physical environment, is arguably the most basic foundation upon which society rests. The integration of the environment, subsistence, and economic exchange and their impacts on other aspects of society are well documented among anthropologists. Theoretical orientations including cultural materialism, cultural ecology, political economy and political ecology all reinforce the key position of the economy in other aspects of society.

Anthropologists also recognize, however, that different components of society change at different rates, creating a cultural lag. And, American society demonstrates a cultural lag between science and empirical thinking on the one hand, and an ideology that’s lagged far behind – an ideology closely akin to magical thinking, on the other. And so, for example, in the face of overwhelming evidence for climate change and global warming, there are those who deny it and attempt to argue against it. And, as Charles Darwin’s 200th birthday approaches – and in light of the tens of thousands of fossils, DNA studies and comparative anatomical investigations that have taken place since Origin of Species was published in 1859 – we still find individuals who will argue vociferously that human beings were created in their present form some 10.000 years ago. Understanding and interpreting data that informs us about our economic crisis presents a similar challenge in today’s world.

Scientists should be actively engaged in responsibly representing and explaining the results of empirical investigations. I’ve always believed that anthropologists have a tremendous responsibility in this regard. We who have inherited hundreds of years of empirical studies focused on our own species (and our close relatives the living primates) – we who devote our own legacies to the further study of humankind – must contribute to resolving the complex and dire problems of the contemporary world.