Zachary Hancock is a postdoctoral researcher at the University of Michigan and specializes in evolutionary genetics.

Evolution by natural selection requires that there exists variation in fitness between individuals. This simple truism goes back to Darwin’s Origin of Species, but where Darwin relied on verbal arguments, the statistician and population geneticist R.A. Fisher sought to codify this basic fact mathematically.

In 1930, Fisher published The Genetical Theory of Natural Selection, and within introduced the fundamental theorem of natural selection (FTNS). The FTNS is, in effect, a restatement of Darwin’s idea on the reliance of natural selection on variation. In words, the FTNS states that the rate of change in a population’s average fitness is equal to the additive genetic variance in fitness at that time. An implication of this is that when there’s a ton of variation in fitness, the population’s average fitness can increase rapidly by natural selection. But if there is very little differences in fitness among individuals, any subsequent fitness increase must be slow or absent entirely.

The basic idea behind the FTNS is quite simple, even if the derivation mathematically has caused many biologists to scratch their heads over the many decades since Fisher first introduced it. Some, like Warren Ewens (Ewens 1989), have argued that Fisher’s theorem is useless, while others, such as George Price (Price 1972), Alan Grafen (Grafen 2003), and Sean Rice (Rice 2004) have contended it is, indeed, a general theorem properly understood. Point here is that the FTNS has been a source of much debate for decades.

In 2018, two creationists wandered into this rather esoteric historic dispute. And as is characteristic of creationists, they did so without a clear appreciation of the field they were embarking to critique and with highly suspect motivations. Bill Basener—a mathematician and data scientist at the University of Virginia—and John Sanford—retired Cornell plant geneticist, inventor of the gene gun, and promoter of “genetic entropy”—together (and “BS” hereafter) published a paper in the Journal of Mathematical Biology titled “The fundamental theorem of natural selection with mutations.”

Continue Reading

Glenn Branch is deputy director of the National Center for Science Education, a nonprofit organization that defends the integrity of American science education against ideological interference. He is the author of numerous articles on evolution education and climate education, and obstacles to them, in such publications as Scientific American, American Educator, The American Biology Teacher, and the Annual Review of Genomics and Human Genetics, and the co-editor, with Eugenie C. Scott, of Not in Our Classrooms: Why Intelligent Design is Wrong for Our Schools (2006). He received the Evolution Education Award for 2020 from the National Association of Biology Teachers.

Stephen Jay Gould’s discussion of the panda’s thumb in his essay of the same name, originally published in 1978, is often misrepresented as describing the false thumb of Ailuropoda melanoleuca as ineffective in practice rather than as inelegant in origin. A recent incidence of such misrepresentation prompted Glenn Branch of the National Center for Science Education to provide his discussion of a similar misrepresentation in a 2000 cartoon presentation of intelligent design, originally published on the Metanexus: The Online Forum on Religion and Science website in two parts on August 15 and 16, 2002. The following appears here in conformity with Metanexus’s republication policy and with Branch’s permission. Minor changes, primarily regarding punctuation, have been made invisibly, and a few updates have been included in square brackets. This is part 1 of 2.

Intelligent design, according to Michael Behe,

must be ranked as one of the greatest achievements in the history of science. The discovery rivals those of Newton and Einstein, Lavoisier and Schrodinger, Pasteur, and Darwin. The observation of the intelligent design of life is as momentous as the observation that the earth goes around the sun or that disease is caused by bacteria or that radiation is emitted by quanta (Behe 1996: 232–233).

Such a great scientific achievement, of course, deserves a careful exposition in a suitably scholarly format. But instead what it received is What’s Darwin Got to Do With It? (henceforth, for brevity, WDGDWI), Robert C. Newman and John L. Wiester’s cartoon treatment of intelligent design (Newman and Wiester 2000).

Continue Reading

To see comments on this post click below:

Continue Reading

Joel Eissenberg is Professor of Biochemistry and Molecular Biology at Saint Louis University School of Medicine. He is the author of the recent PT article, How humans lost their tails.

As a college junior, I took a course in microbial genetics. The text was Gunter Stent’s Molecular Genetics. I map the beginning of my career as a geneticist to that course. Stent’s book is a history of the origins of molecular biology, and in retrospect, I believe it was the combination of the history and the science that beguiled me. This potent combination is on offer in Siddhartha Mukherjee’s The Song of the Cell: An Exploration of Medicine and the New Human. I generally avoid popular science books in my field, but this book was a gift from my daughter. I had read and enjoyed Mukherjee’s The Emperor of all Maladies, so I was hoping for something special. I was not disappointed.

The factual information about cells and their roles in tissues and organs, and in disease were well established by the time most of us learned it in school, we mostly learned it by rote. Mukherjee uses the history of scientific discoveries about cells to show us not only each discovery, but also the context in which it was made and the impact it had on thinking at the time. Indeed, the book is chock-a-block with historical anecdotes. Many of these discoveries were controversial at the time, like germ theory as the basis for putrefaction and for disease. The esteemed evolutionary biologist Ernst Mayr mocked Carl Woese’s proposal of Archea as a third kingdom of life; Mayr was wrong and Woese was vindicated. Even today, the origins of eukaryotic cells are still controversial.

Mukherjee is a marvelous storyteller. For example, he tells the story that when lipids were extracted from a carefully measured number of red blood cells and spread out on a surface, the area was twice that necessary to contain that number of cells, pointing to a lipid bilayer, rather than monolayer. He is very effective at explaining how discoveries emerge at the confluence of scientific disciplines; e.g., the marriage of microscopy and biochemistry to define the functions of various organelles.

Continue Reading

Joel Eissenberg is a professor of Biochemistry and Molecular Biology at Saint Louis University School of Medicine. His research interests include transcriptional control of gene expression and vesicle trafficking. He has had a lifelong fascination with genomics and with developmental biology.

In a recent Nature paper, Xia et al. offer a mechanistic explanation for tail-loss evolution in humans and anthropomorphous apes. It turns out that loss of a tail is caused by loss of a gene function among the tailless primates. And as the paper shows, this evolutionary transition was mediated by transposable elements, that is, repeated parasitic DNA fragments that are found in all living things.

Continue Reading