Category Archives: Science

Can we trust radiocarbon dating? Update; full paper available

Full paper cited here now publicly available at
https://www.asa3.org/ASA/PSCF/2018/PSCF6-18Davidson.pdf

Primate's Progress

Willard Frank Libby, inventor of the method

Can we trust radiocarbon dating? Young Earth creationists tell us that we can’t. After all, it makes the same range of assumptions as other radiometric dating methods, and then some. Other methods benefit from internal checks or duplications, which in the case of radiocarbon dating are generally absent. There are numerous cases where it appears to give absurdly old ages for young material, while apparent ages of a few tens of thousands of years are regularly reported for material known on other evidence to be millions of years old. So can the Young Earth creationist1 objections be rebutted, and if so how?

The principle of radiometric dating is simple.2 If we know how much of a particular radioactive substance was present when a material formed, how much is still there, and

View original post 3,141 more words

Teaching evolution in Kentucky, 2: The Case of the Ivory-billed Woodpecker

The thing about teaching is we are never sure we are making a difference.

Jim Krupa takes evolution as his central theme when he teaches biology to non-majors at the University of Kentucky, where the students are most unlikely to have heard about evolution in school, but may well have been warned about its wickedness in church. With his permission, I am posting an article that he wrote in Orion Magazine describing his experiences. The first part dealt with the challenges he faces. This second part describes his response, which centres on a discussion of the nature of scientific reasoning, followed by the case study (described in greater detail[1]in’s American Biology Teacher), and concludes with a discussion of outcomes. Notice how many misconceptions Jim demolishes on the way, including confusion about the  role of theory in science, the curious but widespread belief that evolution science is without practical application, and (particularly important in his local context) the claim that accepting evolution is incompatible with religion.

Jim teaches, and touches the lives of, 1800 students a year – enough, over time, to flip a good few school districts and make a real difference to the cultural climate of the State. And we can be sure that his students will have plenty to talk about with their friends.

Defending Darwin (continued)

By James Krupa

Ivorybill

The (now-extinct) Ivory-build Woodpecker, central to Prof Krupa’s case study

ONCE I LAY DOWN the basics of science, I introduce the Darwinian theories of evolution. Charles Darwin was by no means the first or only to put forth evolution; others came before him including his grandfather, Erasmus Darwin, who wrote about descent with modification. Later, while Charles was amassing evidence in England for natural selection, one of the most eloquent scientific theories ever, Alfred Russel Wallace was also developing the same theory during his travels in Indonesia. But it was Charles Darwin alone who advanced the theory of descent with modification, with his bold idea that all species belong to the same tree of life and thus share a common ancestor. He also gave us sexual selection theory, which explains how evolution is shaped by competition for mates as well as choice of mates. Too often only natural selection and descent with modification are emphasized in introductory biology classes. I also cover Darwin’s theories of gradualism (including the nuance of punctuated equilibrium); descent from a common ancestor; multiplication of species; and sexual selection. I emphasize that five of the theories explain the patterns of evolution, while natural and sexual selection are the mechanisms that drive evolution. Read the rest of this entry

Teaching evolution to creationists in Kentucky (by one who does it for a living)

Evolution and scientific logic lie at the heart of Prof Jim Krupa’s award-winning biology course at the University of Kentucky, conveyed by a mixture of story-telling, the Socratic method, and student engagement in a case study close to his heart as a naturalist. Jim has kindly agreed to let me post his article in Orion Magazine. The first part (here) describes the  hostile cultural environment in which he is working, why evolution is at the core of his teaching, and how he begins his course by clearing away semantic nonsense, and analysing the concept of scientific theory.

You will find more detail about this in one of his articles in The American Biology Teacher [1]. Jim uses the National Academies definition of a scientific theory as well-attested by observation, but, as he explains there, he is well aware of its limitations, and  anatomises “the” theory of evolution into its separate independent components, before bringing them to bear on the case study that I will be describing the second part of this two-part series.

Defending Darwin

By James Krupa

I’M OFTEN ASKED what I do for a living. My answer, that I am a professor at the University of Kentucky, inevitably prompts a second question: “What do you teach?” Responding to such a question should be easy and invite polite conversation, but I usually brace for a negative reaction. At least half the time the person flinches with disapproval when I answer “evolution,” and often the conversation simply terminates once the “e-word” has been spoken. Occasionally, someone will retort: “But there is no evidence for evolution.” Or insist: “It’s just a theory, so why teach it?”

File:WilliamtyounglibraryUK.JPG

University of Kentucky library building

At this point I should walk away, but the educator in me can’t. I generally take the bait, explaining that evolution is an established fact and the foundation of all biology. If in a feisty mood, I’ll leave them with this caution: the fewer who understand evolution, the more who will die. Sometimes, when a person is still keen to prove me wrong, I’m more than happy to share with him an avalanche of evidence demonstrating I’m not.

Some colleagues ask why I bother, as if I’m the one who’s the provocateur. I remind them that evolution is the foundation of our science, and we simply can’t shy away from explaining it. We don’t avoid using the “g-word” when talking about gravitational theory, nor do we avoid the “c-word” when talking about cell theory. So why avoid talking about evolution, let alone defending it? After all, as a biologist, the mission of advancing evolution education is the most important aspect of my job.

an institution steeped in the history of defending evolution education

TO TEACH EVOLUTION at the University of Kentucky is to teach at an institution steeped in the history of defending evolution education. The first effort to pass an anti-evolution law (led by William Jennings Bryan) happened in Kentucky in 1921. It proposed making the teaching of evolution illegal. The university’s president at that time, Frank McVey, saw this bill as a threat to academic freedom. Three faculty members—William Funkhouser, a zoologist; Arthur Miller, a geologist who taught evolution; and Glanville Terrell, a philosopher—joined McVey in the battle to prevent the bill from becoming law. They put their jobs on the line. Through their efforts, the anti-evolution bill was defeated by a forty-two to forty-one vote in the state legislature. Consequently, the movement turned its attention toward Tennessee.

File:Funkhouser building.jpg

The Funkhouser building. Funkhouser, then Professor of Zoology, was among those who successfully campaigned against a 1921 State bill that wold have made the teaching of evolution illegal.

John Thomas Scopes was a student at the University of Kentucky then and watched the efforts of his three favorite teachers and President McVey. The reason the “Scopes Monkey Trial” occurred several years later in Dayton, Tennessee—where Scopes was a substitute teacher and volunteered to be prosecuted—was in good part due to the influence of his mentors, particularly Funkhouser. As Scopes writes in his memoir, Center of the Storm: “Teachers rather than subject matter rekindled my interest in science. Dr. Funkhouser . . . was a man without airs [who] taught zoology so flawlessly that there was no need to cram for the final examination; at the end of the term there was a thorough, fundamental grasp of the subject in bold relief in the student’s mind, where Funkhouser had left it.”

I was originally reluctant to take my job at the university when offered it twenty years ago. It required teaching three sections of non-majors biology classes, with three hundred students per section, and as many as eighteen hundred students each year. I wasn’t particularly keen on lecturing to an auditorium of students whose interest in biology was questionable given that the class was a freshman requirement.

Then I heard an interview with the renowned evolutionary biologist E. O. Wilson in which he addressed why, as a senior professor—and one of the most famous biologists in the world—he continued to teach non-majors biology at Harvard. Wilson explained that non-majors biology is the most important science class that one could teach. He felt many of the future leaders of this nation would take the class, and that this was the last chance to convey to them an appreciation for biology and science. Moved by Wilson’s words, and with the knowledge that William Funkhouser once held the job I was now contemplating, I accepted the position. The need to do well was unnerving, however, considering that if I failed as a teacher, a future Scopes might leave my class uninspired.

I quickly came to the conclusion that, since evolution is the foundation upon which all biology rests, it should be taught at the beginning of a course, and as a recurring theme throughout the semester.

I realized early on that many instructors teach introductory biology classes incorrectly. Too often evolution is the last section to be taught, an autonomous unit at the end of the semester. I quickly came to the conclusion that, since evolution is the foundation upon which all biology rests, it should be taught at the beginning of a course, and as a recurring theme throughout the semester. As the renowned geneticist Theodosius Dobzhansky said: “Nothing in biology makes sense except in the light of evolution.” In other words, how else can we explain why the DNA of chimps and humans is nearly 99 percent identical, and that the blood and muscle proteins of chimps and humans are nearly identical as well? Why are these same proteins slightly less similar to gorillas and orangu­tans, while much less similar to goldfish? Only evolution can shed light on these questions: we humans are great apes; we and the other great apes (gibbons, chimps, gorillas, bonobos, and orangutans) all evolved from a common ancestor.

Soon, every topic and lecture in my class was built on an evolutionary foundation and explained from an evolutionary perspective. My basic biology for non-majors became evolution for non-majors. It didn’t take long before I started to hear from a vocal minority of students who strongly objected: “I am very offended by your lectures on evolution! Those who believe in creation are not ignorant of science! You had no right to try and force evolution on us. Your job was to teach it as a theory and not as a fact that all smart people believe in!!” And: “Evolution is not a proven fact. It should not be taught as if it is. It cannot be observed in any quantitative form and, therefore, isn’t really science.”

We live in a nation where public acceptance of evolution is the second lowest of thirty-four developed countries, just ahead of Turkey. Roughly half of Americans reject some aspect of evolution, believe the earth is less than ten thousand years old, and that humans coexisted with dinosaurs. Where I live, many believe evolution to be synonymous with atheism, and there are those who strongly feel I am teaching heresy to thousands of students. A local pastor, whom I’ve never met, wrote an article in The University Christian complaining that, not only was I teaching evolution and ignoring creationism, I was teaching it as a non-Christian, alternative religion.

There are students who enroll in my courses and already accept evolution. Although not yet particularly knowledgeable on the subject, they are eager to learn more. Then there are the students whose minds are already sealed shut to the possibility that evolution exists, but need to take my class to fulfill a college requirement. And then there are the students who have no opinion one way or the other but are open-minded. These are the students I most hope to reach by presenting them with convincing and overwhelming evidence without offending or alienating them.

a question I’ve heard many times: “If we evolved from monkeys, why are there still monkeys?”

Some students take offense very easily. During one lecture, a student asked a question I’ve heard many times: “If we evolved from monkeys, why are there still monkeys?” My response was and is always the same: we didn’t evolve from monkeys. Humans and monkeys evolved from a common ancestor. One ancestral population evolved in one direction toward modern-day monkeys, while another evolved toward humans. The explanation clicked for most students, but not all, so I tried another. I asked the students to consider this: Catholics are the oldest Christian denomination, and so if Protestants evolved from Catholics, why are there still Catholics? Some students laughed, some found it a clarifying example, and others were clearly offended. Two days later, a student walked down to the lectern after class and informed me that I was wrong about Catholics. He said Baptists were the first Christians and that this is clearly explained in the Bible. His mother told him so. I asked where this was explained in the Bible. He glared at me and said, “John the Baptist, duh!” and then walked away.

a biology colleague asked … if I would be teaching evolution as a theory or a fact.

To truly understand evolution, you must first understand science. Unfortunately, one of the most misused words today is also one of the most important to science: theory. Many incorrectly see theory as the opposite of fact. The National Academy of Sciences provides concise definitions of these critical words: A fact is a scientific explanation that has been tested and confirmed so many times that there is no longer a compelling reason to keep testing it; a theory is a comprehensive explanation of some aspect of nature that is supported by a vast body of evidence generating testable and falsifiable predictions.

In science, something can be both theory and fact. We know the existence of pathogens is a fact; germ theory provides testable explanations concerning the nature of disease. We know the existence of cells is a fact, and that cell theory provides testable explanations of how cells function. Similarly, we know evolution is a fact, and that evolutionary theories explain biological patterns and mechanisms. The late Stephen Jay Gould said it best: “Evolution is a theory. It is also a fact. And facts and theories are different things, not rungs in a hierarchy of increasing certainty. Facts are the world’s data. Theories are structures of ideas that explain and interpret facts.”

Theory is the most powerful and important tool science has, but nonscientists have perverted and diluted the word to mean a hunch, notion, or idea. Thus, all too many people interpret the phrase “evolutionary theory” to mean “evolutionary hunch.”

Not surprisingly, I spend the first week of class differentiating theory from fact, as well as defining other critical terms. But I’m appalled by some of my colleagues who, despite being scientists, do not understand the meaning of theory. As I was preparing to teach a sophomore evolution class a few years ago, a biology colleague asked how I was going to approach teaching evolution. Specifically, he asked if I would be teaching evolution as a theory or a fact. “I will teach evolution as both theory and fact,” I said, trying hard to conceal my frustration. No matter. My colleague simply walked away, likely questioning my competence to teach the class.

Hear a conversation with James J. Krupa about his experience teaching evolution.

Read the rest of this entry

Behe demolishes Darwin (yet again!)

Michael Behe has a new book coming out, Darwin Devolves, which according to the mendaciously mislabelled Evolution News “Topples Foundational Claim of Evolutionary Theory.” I am unlikely to be sent a review copy, so I am relying on the Evolution News summary.

In brief, Behe continues to assert the existence of irreducible complexity in animal organs, while maintaining that

Darwinian evolution proceeds mainly by damaging or breaking genes, which, counter-intuitively, sometimes helps survival. In other words, the mechanism is powerfully de-volutionary. It promotes the rapid loss of genetic information.

and encapsulates this conclusion in what he calls the First Rule of Adaptive Evolution:

Break or blunt any gene whose loss would increase the number of offspring.

I reviewed Behe’s earlier statement of this Rule some years ago, in PandasThumb, and friends have suggested that I repost it. So here it is. (I am proud to say that it has already been reposted by Peaceful Science.

Since this First Rule of Adaptive Evolution, the pinnacle of Behe’s argument, was already spelt out in the earlier work, there is little that I need add to my original review below, beyond pointing out that even this puny statement of the obvious came with a debilitating disclaimer

It is called a “rule” in the sense of being a rule of thumb. It is a heuristic, useful generalization, rather than a strict law; other circumstances being equal, this is what is usually to be expected in adaptive evolution

and reminding Behe that he is himself the product of a massive increase in genetic complexity, the doubling and redoubling of the genome that separates him from his early notochord ancestors.  The original review follows [note: in that review I referred to “E.Coli acquiring the ability to metabolise citrate under anaerobic conditions”; that should be “aerobic conditions, in the absence of a reducing agent”. h/t Monica Lewis. this does not, however, affect the logic of the argument]:

Behe’s review in context, or what’s the point?

The Panda's Thumb Read the rest of this entry

Why climate skepticism is not skepticism

Sourcing Skepticism … what factors drive questioning of Global Warming?

Copied wth permission of the author, Adam Siegel, from http://getenergysmartnow.com/2007/09/13/sourcing-skepticism-what-factors-drive-questioning-of-global-warming/

The original was posted on September 13th, 2007 and attracted 23 Comments

Now it seems more relevant than ever, with such “skepticism” the posture of governments from Australia to Washington while the Arctic ice melts and methane begins to rise from the tundra.

Skepticism … the ability to question unquestioned beliefs and stated certainties is a powerful intellectual tool.

Sadly, “skepticism” is receiving a bad name through association with those ready, willing, able, and enthusiastic about denying the reality before their (and our) own eyes about the global changes in climate patterns and humanity’s role in driving these changes.

Questioner … Skeptic … Denier …

Clearly, not every question, not every challenge to data, not every voicing of concern is the same.  Nor is every motivation the same.  This is not simply about “fossil-fuel-funding” — although it can be at times. This is not simply about seeking Rapture and the end of times — even though it can be.  This is not simply about political beliefs creating thought structures for dealing with science — but it can be. Read the rest of this entry

The Scopes “Monkey trial”, Part 2: Evidence, Confrontation, Resolution, Consequences

This weekend sees the 93rd anniversary of the Scopes Trial, and I am reposting this and its companion piece to celebrate.

I would point out two things. One is that the actual William Jennings Bryan was nothing like the ogre of Inherit the Wind, which was an allegory of McCarthyism. The other is how remarkably well the scientific evidence has stood up to almost a century of examination. There is even a mention, based on serological evidence, of how closely related whales are to hoofed land animals.

Primate's Progress

Darrow: Did you ever discover where Cain got his wife?

Bryan: No, sir; I leave the agnostics to hunt for her.

Both sides, I will argue, were long-term loses in this exchange. But why were such matters being discussed in Tennessee court of law in the first place?

Part 1: the story so far: An extraordinary case indeed, where a school teacher, with the encouragement of his own superintendent, volunteers to go on trial in the State court for the crime of teaching from the State’s approved textbook, and where that same superintendent will be the first witness called against him. And where a mere misdemeanour case, with a maximum penalty of $500, could attract the participation of William Jennings Bryan, former US Secretary of State, and Clarence Darrow, America’s most famous trial lawyer and an agnostic.

BillySundayPreaching Billy Sunday preaching

In the run-up to the case, we even have the…

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The Scopes “Monkey trial”, Part 1: Issues, Fact, and Fiction

This weekend sees the 93rd anniversary of the Scopes Trial, and I am reposting this and its companion piece to celebrate.

I would point out two things. One is that the actual William Jennings Bryan was nothing like the ogre of Inherit the Wind, which was an allegory of McCarthyism. The other is how remarkably well the scientific evidence has stood up to almost a century of examination. There is even a mention, based on serological evidence, of how closely related whales are to hoofed land animals.

Primate's Progress

What is the purpose of this examination?

We have the purpose of preventing bigots and ignoramuses from controlling the education of the United States, and that is all.

DaytonCourthouse Dayton Courthouse today

Inherit the Wind, the prism through which the public sees the Scopes Trial, is a travesty. William Jennings Bryan, who prosecuted Scopes, was neither a buffoon nor a biblical literalist but moved by deep concerns that continue to merit attention. He did not protest at the leniency of Scopes’s punishment, but offered to pay the fine out of his own pocket. Nor did he collapse in defeat at the end of the trial, but drove hundreds of miles, and delivered two major speeches, before dying in his sleep a week later. Scopes, on trial for the crime of teaching evolution in Tennessee state school, was never at risk of prison. He was no martyr, but a willing participant…

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Can we trust radiocarbon dating?

Willard Frank Libby, inventor of the method

Can we trust radiocarbon dating? Young Earth creationists tell us that we can’t. After all, it makes the same range of assumptions as other radiometric dating methods, and then some. Other methods benefit from internal checks or duplications, which in the case of radiocarbon dating are generally absent. There are numerous cases where it appears to give absurdly old ages for young material, while apparent ages of a few tens of thousands of years are regularly reported for material known on other evidence to be millions of years old. So can the Young Earth creationist1 objections be rebutted, and if so how?

The principle of radiometric dating is simple.2 If we know how much of a particular radioactive substance was present when a material formed, how much is still there, and Read the rest of this entry

Grand Canyon Unconformities –and a Cambrian Island

I have discussed the Grand Canyon myself at https://paulbraterman.wordpress.com/2018/03/09/why-science-needs-philosophy-cont-and-why-it-matters-with-examples-from-geology/ , and strongly recommend this beautifully written and illustrated guide to its unconformities

geologictimepics

A prominent ledge punctuates the landscape towards the bottom of the Grand Canyon. It’s the Tapeats Sandstone, deposited during the Cambrian Period about 520 million years ago, when the ocean was beginning to encroach on the North American continent, an event called the Cambrian Transgression. Above the ledge, you can see more than 3000 feet of near-horizontal sedimentary rocks, eroded into cliffs and slopes depending on their ability to withstand weathering and erosion. These rocks, deposited during the rest of the Paleozoic Era, are often used to demonstrate the vastness of geologic time–some 300 million years of it.

View of the Grand Canyon from the South Rim trail. Arrows point to the Cambrian Tapeats Sandstone. View of the Grand Canyon from the South Rim trail. Arrows point to the Tapeats Sandstone.

But the razor-thin surface between the Tapeats and the underlying Proterozoic-age rock reflects the passage of far more geologic time  –about 600 million years where the Tapeats sits on top the sedimentary rocks of the Grand…

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Why historical science is the best kind of science

This is for a planned wide-audience writing project on evolution, in which I pre-empt (rather than respond to) creationists’ counter-arguments, such as their downplaying of historical science. I would greatly value comments on this approach.

There are sciences, such as physics and chemistry, where we can perform experiments. There are other sciences, such as the science of planetary motion (and astronomy in general) where we cannot do this, but we can still carry out repeated observations in well-controlled circumstances, and devise theories with whose help we can make definite predictions. All of these are what I will call rule-seeking sciences. At the other extreme, we have sciences such as palaeontology and much of geology, which one might call historical sciences.1 With these, the aim is not so much to establish general rules, as to unravel and explain the specifics of what happened in the past. It is usual to regard the rule-seeking sciences as the most rigorous, to which the others should defer. This shows a deep misunderstanding of how science works, and, time and time again, when historical and rule-seeking sciences have come into conflict, it is historical science that has triumphed.

Rocks exposed at Grand Canyon, from Proterozoic to Permian. Click to enlarge

A few examples. The rocks clearly show (for detailed arguments, see e.g. here) that the Earth, and by implication the Sun, Read the rest of this entry

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