Archive for the 'Evolution' Category

Apr 25 2017

New Study of The Hobbit

Published by under Evolution

HobbitI have been following the story of Homo floresiensis for the last decade, and it is fascinating. The remains of a diminutive humanoid were found on the island of Fores in Indonesia. The remains date to about 54,000 years ago. The findings immediately sparked debate, with two primary schools of thought emerging.

The first hypothesized that H. foresiensis (nicknamed the Hobbit due to their small size) was a new species of hominin, likely evolve from H. erectus and displaying an example of island dwarfism. The second argued that the remains are not a new species at all and represent a pathological H. sapiens (modern human).

The two groups have argued back and forth in the scientific literature over the years. It is, in fact, a great example of the scientific method in action. Each group brought new evidence and a new perspective to bear, and had the burden of proof to demonstrate their hypothesis. They fought it out with science and evidence.

I and many others sat of the sidelines and watched the epic battle of science. I admit I was rooting for H. floresiensis, but we would all have to listen to the evidence, whatever it showed.

It’s also a good example of the limitations of mainstream science reporting. Each time a study was published, favoring one side of the debate or the other, it was reported as if the debate were finally over and now we know the answer. Instead they should have put that one study into context – this is just another round in an ongoing debate. The fight isn’t really over until one side concedes defeat and a consensus emerges. Even then, new evidence may trump the consensus, but at least we have a consensus rather than a controversy.

The New Study Continue Reading »

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Mar 27 2017

More on Bird Evolution

bird_evoThe fossil evidence for the evolution of birds is currently one of the greatest evolutionary stories we have to tell. It is also a home run for the predictive value of evolutionary theory and is a devastating blow to any denial of common descent.

Darwin published On the Origin of Species in 1859. At that time the fossil record was sparse, although it was enough to establish that the forms of living things was changing over geological time. One of the most dramatic gaps in the fossil record at the time was between birds and other vertebrates. It was believed that birds must have evolved from some type of reptile, but the most recent common ancestor was not known.

This was a great test for the new theory of evolution. If evolution were true then birds must have evolved from something else, and therefore the gap between birds and their closest non-avian relative should eventually be filled in by future fossil finds. If evolution is true, those creatures must have existed.

If, on the other hand, some version of creationism were true so that was created close to its current form, then there would not have to be any creatures filling in the morphological space between birds and their closest relatives. Birds would not have any relatives, they would be an isolated group unto themselves.

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111 responses so far

Dec 13 2016

Feathered Dino Tail Trapped in Amber

amber-feathered-tail2Lida Xing from the China University of Geosciences in Beijing was walking through an amber market in Myitkina, Myanmar when he discovered a rather interesting specimen. The seller believed that the large chunk of fossilized tree sap they were selling contained plant material. Xing recognized that it contained primitive feathers. Even more exciting, those feathers were not connected to a bird ancestor, but to the tail of a dinosaur.

A scientific analysis of that specimen has now been published in Current Biology.

This is a tremendous specimen for a number of reasons. Scientists interested in the evolution of feathers have been trying to piece together the developmental steps that occurred and in what order in order to transform scales into feathers. Developmental biology itself provides some clues – the path that feathers take when they develop in the embryo likely reflect their evolutionary history. It would be nice, however, to confirm this hypothesis with actual specimens.

Up until now paleontologists have had two kinds of fossil feathers. The first is feather impressions associated with fossil specimens. The advantage of this kind of evidence is that we know exactly what species the feathers belong to and so they can be placed in a phylogenetic tree of feathered dinosaurs, both avian and non-avian. The disadvantage is that the feather impression are compressed, so the three-dimensional information may be lost, and they often lack fine detail.

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Sep 19 2016

Bacteria Evolving Resistance

Researchers at Harvard did a clever thing. They created a giant plate on which to grow bacteria, and included in the plate increasing concentrations of an antibiotic as you moved toward the center. They then plated bacteria on the outer edges and made a time-lapse video of the bacteria growing.

The end result was a video showing the evolution of progressive antibiotic resistance in the bacteria. You can actually see adaptive radiation, as the bacteria push up against the boundary to the next higher concentration of antibiotics, then multiple locations start to spawn new colonies spreading in the next zone.

The researcher made some more nuanced observations as well. For example, the bacterial grow slowed with new mutations, meaning they sacrificed something with the resistance mutation, but then they sped up again as they further evolved. Further, the most resistant bacteria were often not at the leading edge but were stuck behind less resistant bacteria.

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Aug 05 2016

Mike Pence Does Not Understand Evolution

Pence-EvolutionIt is my universal experience, after more than thirty years of confronting various forms of evolution denial or creationism, that creationists simply do not understand evolution. If any do understand it, they pretend not to. I guess they have no choice – they are motivated to deny an established scientific theory. They need to pretend they know better than the world’s experts, or that the world’s experts are lying and deceitful.

Mike Pence is a run-of-the-mill creationist. His denial of evolution is unremarkable and unimaginative, but now he is running for Vice President so his views serve as a ripe target for criticism. In a speech before the House he decided, for some reason, to go on a rant against evolution. For those who are interested, it is a good opportunity to play “name that logical fallacy” and you may want to watch the video and count the errors before reading ahead.

Pretty much everything Mike Pence says in the speech is wrong or misleading, except for trivial facts. He starts by setting the stage with Darwin publishing On the Origin of Species and presenting the theory of evolution. That evolution is just a “theory” is a main theme of his speech, which I will get to in a moment, but first he follows up by saying that Darwin expected his theory to be proven correct by the fossil record. He concludes that Darwin did not live to see this happen, and neither have we.

Is Evolutionary Theory Proven? Continue Reading »

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May 27 2016

A Tale of Two Science News Reports

parviceps

One of the recurring themes of this blog, and of the skeptical movement itself, is that science news reporting is generally poor. It is highly variable – there are some excellent science news reporters out there, but most are mediocre and some are terrible. The problem is that the average quality is simply too low.

The problem is compounded by the fact that scientists sometimes overhype or overinterpret their results, but even more common, the press office for the university at which the scientists work often sensationalize the science. At every step there is an opportunity to add hype, misinterpret the actual results, sensationalize, focus on the speculative aspect of the study rather than the actual data, or simply get the story wrong.

The race for clicks seems to be driving the quality of science reporting down, favoring clickbait headlines. Reporters don’t seem to mind getting the story wrong and then being corrected by science bloggers, for then they just get another round of clicks correcting their own bad reporting as if it were someone else’s fault.

Sclerocormus parviceps Continue Reading »

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Apr 08 2016

Answering Creationist’s Unanswerable Questions

creationist-videoPointing out how completely illogical and unscientific are creationists is something I need to do on a regular basis here. A creationist who regularly trolls the SGU Facebook page recently posted this video, which is a great opportunity to meet my creationist debunking quota.

Like all creationist propaganda, the video does not make any serious or legitimate scientific points. The purpose is just to provide a plausible screen for denying one of the most solid scientific facts every established – that life on Earth is the product of organic evolution.

The video is a collection of “gotcha” ambushes of students and scientists, asking them loaded questions that defy a simple answer (because first you would have to unpack all the false assumptions in the question itself). It’s natural to pause after such a question, while considering how best to approach it. The segments often cut out after the initial partial response followed by a “gotcha” follow up statement by the interviewer.

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17 responses so far

Sep 24 2015

44 Reasons Creationists are Deceptive, Final Installment

This week I have been making my way through a list of old and debunked creationist arguments put together by Michael Snyder (a young-earth creationist), giving the old arguments new life on social media. As science communicators we often have to play this game of whack-a-mole, persistently addressing points that have already been refuted. Each time is an opportunity to educate more people about the real science of evolution, about logic and critical thinking, about science in general, and the vacuous and deceptive arguments of the science deniers.

This is the fourth and final installment of this series of posts. You can find the others here: Part I, Part II, and Part III.

The next five points that Snyder raises are all variations on the same theme:

#30 Which evolved first: blood, the heart, or the blood vessels for the blood to travel through?

#31 Which evolved first: the mouth, the stomach, the digestive fluids, or the ability to poop?

#32 Which evolved first: the windpipe, the lungs, or the ability of the body to use oxygen?

#33 Which evolved first: the bones, ligaments, tendons, blood supply, or the muscles to move the bones?

#34 In order for blood to clot, more than 20 complex steps need to successfully be completed. How in the world did that process possibly evolve?

Snyder, of course, is asking a false question, one with an unstated major premise that is wrong, or at least misleading. The implication he is trying to make is essentially the debunked notion of irreducible complexity – that complex structures or biological systems could not have evolved because they could not have simpler functional states.

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Sep 24 2015

44 Reasons Creationists Are Deceptive further cont.

This is the third post dealing with a recent aggregation of old creationist arguments that has been making the rounds on social media, 44 Reasons Why Evolution Is Just A Fairy Tale For Adults.  The author, Michael Snyder, has shown a typical level of horrific scholarship and reasoning. Post 1 is here, and post 2 is here.

In the last article I discussed the claim that the Coelacanth is a “living fossil” (a term I despise because it is ripe for confusion). Essentially Snyder and other creationists treat the Coelacanth as if it is a specific species, when in fact it is an order of fish. An order surviving for hundreds of millions of years is not at all unusual.

In the next of Snyder’s reasons he commits the same mistake:

#18 According to evolutionists, the Ancient Greenling Damselfly last showed up in the fossil record about 300 million years ago.  But it still exists today.  So why hasn’t it evolved at all over the time frame?

This claim is entirely wrong, demonstrating sloppy research. Actually I suspect that Snyder did no research (and here I am just referring to looking up reliable references). He seems to have just swallowed a creationist meme whole from the Institute for Creation Research, specifically an article by their “science writer” Brian Thomas.

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31 responses so far

Aug 14 2015

Dating Hominin Tool Use

Published by under Evolution

When did our ancestors first start to use tools? That is a very interesting question, and immediately leads to the question of how we could know. What kind of evidence could there be to establish human tool use?

The most obvious evidence would be the tools themselves. Fortunately stone tools are made of stone, which is highly durable and can last millions of years. Earlier this year researchers published evidence of the now earliest known stone tools, from 3.3 million years ago. This finding was significant for several reasons.

First, it pushed back tool use 700,000 years. Perhaps even more significant, prior to this find the oldest confirmed stone tools were associated with the species Homo habilis, the first of the Homo genus that led to modern humans. It could therefore be said that sophisticated tool use (meaning modified tools that can be recognized) was unique to the Homo genus. These new tools, called the Lomekwian tool culture, predate Homo habilis, and are likely associated with Australopithecus afarensis.

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