Bill Nye recently produced a video as part of the Big Think series on YouTube, this one arguing that creationism is not appropriate for children. The video has sparked some debate, but not just about evolution and creationism – more so about tone and strategy. What is the purpose of the video, and is it successful?

One of the interesting corners of this discussion is two articles on Scientific American taking two very different views of the video. The first is an interview with Patrick Donadio, “a professional speaker and a communications coach to the leaders of Fortune 500 companies.” The second is essentially a rebuttal by Kyle Hill, which takes a more scientific view. Naturally, I related better to the second article.

Hill points out that there is actually some published evidence on communication that might inform this discussion – something missing from Donadio’s interview. I have had some experience with corporate-style communications “experts” and I have had the same reaction as Hill appears to gently be stating – that there is a culture of corporate speaking and self-styled experts that is not exactly compatible with scientific communication.

Continue Reading »

Published in Nature this month is a report of the entire genetic sequence of Musa acuminata – the Cavendish banana. The banana is the most popular fruit in the industrialized world. Banana varieties are also an important staple crop in much of the world. The Cavendish, however, is threatened by two fungal infections – Panama disease and black leaf streak disease. Hopefully knowledge gained from the banana genome will lead to new varieties of acuminata that are resistant.

Part of the problem is that the Cavendish is a highly cultivated variety. Starting about 7,000 years ago the banana was cultivated by hybridization of various varieties. Interestingly, most acuminata varieties are triploid, meaning they have three copies of each chromosome, while some are diploid with two copies. Diploid and triploid varieties were hybridized together.

One trait in particular that was selected for was being seedless. Most banana varieties contain numerous large seeds. The Cavendish has none, which makes it an attractive variety as a dessert fruit. However, this also means that there is no longer any sexual recombination within the Cavendish variety. Every Cavendish banana  plant (representing about half of all bananas in the world) is a somaclone derived from the single variety. A somaclone refers to a plant derived ultimately from a single somatic parent cell. This means that every Cavendish banana plant is virtually identical genetically to every other. They are not strictly identical because somaclone variability is possible through spontaneous somatic mutations.  But variation is minimal.

Continue Reading »

Science makes predictions. That is inherent to the scientific process. It’s what makes hypotheses testable – they make predictions about what will be observed in nature, about the outcome of experiments, and about future trends and events. Scientific theories are really models that allow us to predict the behavior of the world, and they are judged on their utility for making such predictions, rather than whether or not they are objectively “correct” (because we can’t know that).

This was a simple point I was trying to make, with respect to evolutionary theory, in a recent post on feathered dinosaurs. Egnor, who fancies himself an evolutionary gadfly, has tried to counter my arguments but only manages to create a confusing mess. In my original post I made the point:

After Darwin published his theory of evolution one of the early challenges to the idea of evolution, which includes the claim that all life on earth is related through common ancestors, was that there were significant gaps between major groups of living creatures. Birds, for example, seem to be their own group without a close connection to any other group. They are, of course, related to vertebrates. But if evolution were true then there must be fossil evidence connecting birds to another group, such as reptiles.

Continue Reading »

The story of feathered dinosaurs is one of the strongest success stories for evolutionary theory, and continues to be a thorn in the side of evolution deniers. They cannot help but expose their ignorance and deception when they clumsily try to deny the implications of feathered dinosaurs. So I tend to revel, just a bit, in each new significant discovery of a feathered dinosaur. The latest discover, recently published in PNAS, provides evidence that feathers were even more common among dinosaurs than previous evidence demonstrated. There is some debate among experts about how prevalent protofeathers and feathers were, and so a new piece of solid fossil evidence helps clarify the debate further.

After Darwin published his theory of evolution one of the early challenges to the idea of evolution, which includes the claim that all life on earth is related through common ancestors, was that there were significant gaps between major groups of living creatures. Birds, for example, seem to be their own group without a close connection to any other group. They are, of course, related to vertebrates. But if evolution were true then there must be fossil evidence connecting birds to another group, such as reptiles.

Right around that time the first specimens of Archaeopteryx were discovered (the London specimen in 1861 and the Berlin specimen in 1874). These are beautiful transitional fossils showing features of both theropod dinosaurs and birds – exactly as Darwin predicted. For decades Archaeopteryx stood as the sole species bridging birds and dinosaurs, and creationists did everything they could to deny the implications of this fossil. They tried calling it a hoax, then just a regular dinosaur, then just a regular bird. They also argued that, whatever it is, there is no proof that it is actually transitional between dinosaurs and birds – a non sequitur that betrays their lack of understanding of evidence in science.

Continue Reading »

Richard Leakey, son of Mary and Louis Leakey, is a deservedly famous paleoanthropologist who has contributed significantly to our understanding of human evolution. In a recent interview he expressed his confidence that skepticism over evolutionary theory will fade away over the next 15-30 years. He is quoted as saying:

“If you get to the stage where you can persuade people on the evidence, that it’s solid, that we are all African, that color is superficial, that stages of development of culture are all interactive,” Leakey says, “then I think we have a chance of a world that will respond better to global challenges.”

While I hope this is true, I am not as optimistic. I think the primary problem with his argument is the premise that you can get to the stage, “where you can persuade people on the evidence.”  In my opinion the evidence indicates that for many people, you cannot persuade them on the evidence. Unfortunately, human psychology simply does not work that way.

I agree with his premise that the evidence for evolution as a fact is overwhelming. In fact, I think we are already there. We do not need to wait 15-30 years for the evidence to be solid and convincing. There is a confluence of evidence from genetics, paleontology, anatomy, and developmental biology that has only one scientific explanation – common ancestry and organic evolution. We’re still working out the details, but the big picture is crystal clear.

Continue Reading »

I need to dip into the topic suggestions more often. Here is a good recent question:

Hi Dr. Novella,

Over at Why Evolution is True Jerry Coyne wrote about Ben Carson, the creationists doctor at Johns Hopkins, saying some bizarre stuff about evolution. In the comments a couple people have made the point that they don’t think understanding evolution is directly relevant to being a doctor (especially a surgeon, ENT, or oncologists). One commenter even said he thought oncologists “have precisely and exactly zero need to understand evolutionary theory.”

I tried to argue that understanding the foundational principle of biology was directly relevant to physicians, in a variety of areas. I am very interesting in your views on the subject. Does understanding evolution help a doctor be better as her/his job? Is understanding evolution going above and beyond as a doctor, or something that should be expected of physicians?

Here’s the link to the main comment I had in mind (#30) and a couple responses, including mine:
http://whyevolutionistrue.wordpress.com/2012/05/16/creationist-sugeon-to-give-commencement-address-at-emory-university/#comment-219290

Thanks!

In my opinion there are two basic questions here: how relevant is evolution to the science of medicine, and how does understanding the science of medicine impact the practice of medicine?

Continue Reading »

Yet another feathered dinosaur has been discovered in China – this one is a relative of T. rex and is the largest creature with feathers, extant or extinct, to have been discovered. Yutyrannus lived about 125 million years ago and is an early cousin of the T. rex.

This is one of my favorite paleontological stories – in fact, it’s one of my favorite science stories because it demonstrates one of the ways in which evolution is testable. When Darwin first proposed his theory the fossil record was very scant. Further, the number of species currently alive is a very small portion of the number of species to have ever lived (scientists are fond of saying that most species to have ever lived are extinct).

This means that when we look at living things in order to infer the relationships among them, different plants and animals might appear to cluster in separate groups. Actually a thorough survey of living things shows a pattern of nestled categories that are blurry at the edges (I’m looking at you, platypus) and nicely reflects a branching pattern of common descent. But still, there do appear to be distinct groups. This appearance, however, is an artifact of the incompleteness of the sample of all living things represented by those species that are still alive.

Continue Reading »

The Tennessee bill that requires science teachers to teach the “strengths and weaknesses” of “controversial” topics has sparked public discussion on evolution and creationism once again. This means that we will cycle through the same series of arguments that have already been worked through, but that is the nature of the popularization of any topic, such as science. Inevitably in these discussions some people, wanting to be accommodating to all sides, ask some version of the famous question, “Can’t we all just get along?”

This view touches our democratic and individualistic sensibilities and our sense of fairness. Further, the political process is often one of compromise. Creationists are happy to exploit these facts, and claim that they just want what’s fair, they want “equal time,” they want to “teach the controversy,” and they just don’t think evolution should get any special treatment. They use these strategies because they resonate with the American culture. Also it’s easy to portray egg-headed intellectual scientists as ivory tower elitists. This all may be effective politics, but it is bad science and bad for education.

A recent editorial in the Tennessean plays the “compatible” card – here it is in its entirety:

Science has proved the universe began with a collision of two specks moving in an oversize void a very long time ago, evolving into what we have today.

How did they get together? Where did they come from? That is where God came in.

What I don’t understand is, why argue over evolution and creation when both theories are true?

Continue Reading »

A century and a half ago scientists knew very little about how life works, at least compared to what we know today. They knew little about the organelles that make up each living cells, the biochemical pathways involved in living processes, and knew absolutely nothing about genetics (which didn’t even exist yet as a discipline). It was in this context of relative ignorance that Charles Darwin proposed his particular theory of evolution and presented his argument for common descent and natural selection. The notion of evolution and common descent predates Darwin – scientists before him noticed a pattern in the sequence of fossils appearing in successive geological layers. Life seemed to be changing over geological time, with species in younger layers seeming to be derived from species in older layers.

Darwin added to that that basic observation his extensive personal observations of nature – that there is actually a great deal of variation within species, and that many species on the Galapagos seem to be derived from related species on the mainland, but changed to adapt to various niches on the islands. Still, evolution through natural selection was a remarkable hypothesis, but little more than a hypothesis. It is perhaps a good thing that there was so much left to discover about basic biology when evolution was proposed, for that created the opportunity to test this crazy theory.

Continue Reading »

You have probably heard of the crocoduck – the impossible chimera that exists only in the pseudoscientific imagination of Kirk Cameron and Ray Comfort. There is also the duckcroc, which is a real creature – an extinct crocodilian with a duck-like snout.

Well now, meet crocochicken. This creature does not yet exist, but only because the scientists who are tinkering with its genetic program are not allowed to let it hatch. Arkhat Abzhanov is an evolutionary biologist at Harvard University. He is engaged in a research program, the goal of which is to reverse some of the evolutionary changes that resulted in birds evolving form theropod dinosaurs. In essence, he want to reverse the evolutionary clock and produce a chicken with more reptilian features.

The particular feature he is working on is the duck’s bill. He is coaxing it down a different developmental path so that it ends up looking more like a crocodiles snout – hence the name “crocochicken.”

There is another researcher also doing similar research. Hans Laarson of McGill University and colleagues are also trying to reverse chicken DNA to develop along more primitive path – he is working at the other end, trying to get chickens to grow a dinosaur-like tail. His creation has been dubbed “dinochicken,” which is a much better term as chickens actually evolved from dinosaurs and not crocodilians.

Continue Reading »