Archive for the 'Evolution' Category

Apr 25 2014

Prebiotic Earth

Published by under Evolution

One of the great scientific mysteries is the specific processes and pathways that led to the first living organisms on earth. This is not mysterious in that we don’t know how it could have happened, it’s just that it is extremely difficult to reconstruct how is actually did happen. Chemical reactions don’t fossilize, and so understanding a complex process that likely took millions of years to unfold billions of year ago is a bit challenging.

Researchers have mostly had to rely on plausibility studies – experiments that show how prebiotic evolution could have happened and extrapolating from data on early earth conditions. More progress has been made with this type of research. The title of the paper says it all – Non-enzymatic glycolysis and pentose phosphate pathway-like reactions in a plausible Archean ocean. (Markus A. Keller, Alexandra V. Turchyn, Markus Ralser)

The researchers showed that, in conditions based upon published literature about the early prebiotic ocean, certain metabolic pathways central to life could happen spontaneously and without the presence of enzymes. That last bit is critical – enzymes are proteins that act as catalysts, which are substances that make a chemical reaction happen faster. Enzymes are critical to life, as the biochemical reactions of life would occur at too slow a rate without them.

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77 responses so far

Feb 11 2014

New Burgess Shale Find

Published by under Evolution

For those familiar with the Burgess Shale, the news of a new “phyllopod bed” is exciting.

A century ago Charles Walcott discovered (in what is now called Walcott quarry) an amazing fossil bed from the Cambrian era. These were soft-bodied fossils preserved in shale from the very dawn of multicellular life, the Cambrian explosion. From 570 to 530 million years ago multicellular plant and animal life appeared in fossils and diversified. Every major group we see today is represented in Cambrian fossil beds, along with phyla that are now extinct. Walcott Quarry is by far the most prolific and best preserved such fossil bed.

Now researchers report on the discovery of another fossil bed 40 km southeast of the Walcott quarry, in Kootenay National Park. The report:

The assemblage, discovered in 2012, occurs at the top of the Burgess Shale Formation and is significantly younger than the localities of the type area. In situ excavation and talus collections from a two-meter thick interval have so far yielded 3053 specimens representing at least 52 taxa. Among these, half are known from the Walcott Quarry and at least 15 are new.

Wow. This is a massive find from somewhat later in the Cambrian, perhaps showing even more early diversity of multicellular life. Already they are finding new species and more details about known species. It may be a little early to speculate, but the researchers feel that this find could be even bigger than the Walcott Quarry.

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8 responses so far

Sep 13 2013

More on Logic and Thermodynamics

Michael Egnor likes to play the game of Name That Logical Fallacy – or at least he likes to set up other people to play that game. He is a creationist neurosurgeon who has been blogging over at Evolution News & Views, an intelligent design propaganda outlet. In a recent post he attempts to reply to my post deconstructing a paper by Graville Sewell in which he claimed that evolution violates the second law of thermodynamics.

Egnor blows his first attempt at naming a fallacy.

Novella begins his critique of Sewell’s argument with the usual Darwinist ad hominem:

“Creationists will just not let go of an argument, no matter how many times it is pointed out to them that their argument is unsound. They simply find new twists of logic and distortions of science to resurrect their precious argument, clinging to it more tightly than Gollum held onto his ring.”

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27 responses so far

Aug 20 2013

Creationism is Not Science

“In fact, we have solid proof in our hands that evolution’s a lie: the Bible. You see, we can’t depend solely on our reasoning ability to convince skeptics. We present the evidence and do the best we can to convince people the truth of God by always pointing them to the Bible.”

The above quote is from Ken Ham, president of Answers in Genesis, from a radio commercial to promote his creation museum. Ham also says:

“You know, many of us would love to have the final proof that evolution’s a lie; the right scientific proof will silence those opposed to biblical creation forever, right? Well, no. You see, Romans Chapter one tells us that God has revealed himself to man in nature, so there’s no excuse for denying the witness of creation.”

These quotes are very revealing in multiple ways. First they show that creationists and creationism are not monolithic – there is a range of beliefs and strategies under the “big tent” of creationism. They are all united by their opposition to evolution, and essentially agree to disagree until the great evil of evolution is vanquished. Meanwhile they are stomping on each-other’s toes.

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95 responses so far

May 31 2013

Final Response from Don McLeroy

Here is it.


We agree that historical sciences like evolution are “tested” by the evidence. My key insight from our discussion is we disagree about the amount of evidence needed to demonstrate evolution. I want to see significantly greater evidence than you do.

I admit that I do not have the time to read all the technical articles and read all the links you have referred to, but I do not admit that I am unable to judge the adequacy of the evidence evolutionists have presented for evolution. I have read the popular literature of highly acclaimed evolutionists; I have thought about how much evidence is required to demonstrate evolution. And, I have found it unconvincing.

Of course our major disagreement is that I am a theist and you are an atheist. I wonder how much that “colors” our view of the sufficiency of the evidence for evolution.

Thank you again for the opportunity to be interviewed on your podcast and to have this this continued dialog. I have truly enjoyed our discussion; you are the proverbial “scholar and a gentleman.” 


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50 responses so far

May 30 2013

Yet Another Fossil Bird – Aurornis xui

Published by under Evolution

Keeping with the recent discussion of the evidence for evolution, I want to discuss another well-preserved fossil bird from the Liaoning Province in China – Aurornis xui, or the dawn bird. As the name implies, this fossil represents what is now the most basal species on the branch that diverted from other dinosaurs and ultimately led to modern birds.

Before I get into the details of this new fossil, let me go over some background, and the implication of these finds for the theory of evolution.

When Darwin proposed his theory in 1859 the fossil record was scant. Already at that time, however, there were enough fossils for geologists to have recognized a pattern – different geological strata contain different assemblages of fossils. They seem to change, or evolve, over geological time. Fossil species do not all arise at one, they are not randomly placed, nor are they the same throughout geological time – they profoundly change.

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47 responses so far

May 28 2013

Don McLeroy Replies

Two weeks ago I wrote a four-part post analyzing the claims of Don McLeroy, former chairman of the Texas Board of Education, based mostly on an interview I did with him on the SGU. The posts also included some responses from Don. Don has been travelling, but has now returned and had time for a thorough response to the entire series of posts. Here is his response in its entirety, with my reply following:


For me, the main topic under discussion is the strength and weakness of the evidence for evolution. My entire argument in 2009 and today is that the evidence supporting evolution—the idea that all life is descended from a common ancestor due to unguided natural processes—is weak.

Again, the key criterion for science is testability. Evolution is overwhelmingly tested historically by making observations—finding evidence. The more evidence found the stronger the case; the less evidence found the weaker the case.

I have read your comments and the comments of others posted on your podcast and NeuroLogica blog posts. Here is the summary of actual evidence that I gleaned from these comments. I probably missed some, but I do not think it invalidates my argument about the weakness of the evidence for evolution.

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46 responses so far

May 17 2013

An Interview with Don McLeroy, Part IV

This is the fourth is a series of posts analyzing the claims of Don McLeroy, former chairman of the Texas School Board of Education and young Earth creationist. I recently interviewed Don on the SGU about his successful insertion into the Texas science textbook standards language requiring books to address stasis and suddenness in the fossil record and the complexity of the cell.

In parts 2 and 3 I addressed Don’s stasis and suddenness arguments. They are classic denialist fallacies – focusing on lower order details as if they call into question higher order patterns (they don’t). In this case, Don is arguing that the fact that many (not all) species display relative morphological stability in the fossil record, with episodes of (geologically) rapid speciation events, calls into question the bigger picture of the change of species over time in an exquisitely evolutionary pattern.

The former is a reflection of the tempo of evolutionary change and an artifact of the fossil record, while the latter is home-run unequivocal evidence for common descent and evolutionary change. Don has not provided any explanation for why the pattern of change we see in the fossil record presents any problems for evolutionary theory.

In this post I will address Don’ other main point, which he feels is the greatest weakness of evolutionary theory – the complexity of the cell. His premise seems to be that, if evolution were true, then evolutionary biologists should be able to provide detailed evidence for the specific evolutionary history of many biochemical pathways and cell structures. He argues that they cannot, and therefore the evidence for evolution is weak.

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29 responses so far

May 16 2013

An Interview with Don McLeroy, Part III

This week I am posting a discussion with Don McLeroy, a young Earth creationist and former chairman of the Texas Board of Education during the recent controversy over the science textbook standards. This is a follow up to an interview I did with him on the SGU.

Don has been traveling a bit this week, so our e-mail conversation has been slow, but we have had a few exchanges. For today’s post I want to simply reprint that exchange and then add a few thoughts, before I go onto new territory, which I will do in tomorrow’s post.

Here is Don’s response to my prior posts:


I do have time for one reply.

First, you keep bringing up creationism while I do not; I am only discussing the evidence for evolution–the idea that all life is descended from a common ancestor as a result of unguided natural processes.

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25 responses so far

May 14 2013

An Interview with Don McLeroy, Part II

In part I of my analysis of a recent interview with Don McLeroy on the SGU I discussed his assertion that those of faith are more free to accept or reject the evidence for evolution, while strict materialists can only accept it as it is the only materialist option. I mentioned in that post that I would invite Don to respond – I did and he did.

In this post I will include Don’s response and then my further analysis of his response. I will then extend the discussion to other points that Don raised during the SGU interview.

Don McLeroy Responds to Part I


Thank you for this opportunity to respond.

We are mirror images of each other. I see you as you see me-as “an excellent example of the power of motivated reasoning,” as “firmly in phase 2,” and as someone who might be considered “embedded” in a culture of their own publications, institutions, and websites.

At least we both agree to follow the evidence where ever it leads.

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36 responses so far

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