email - April 2013

Foolish Falcons

This article is for the birds.

Mick alerted us to this BBC Nature article.

Hello David

I've just read one of the worst-informed articles on evolution I've known. http://www.bbc.co.uk/nature/21885659 says that researchers have sequenced falcon DNA to unravel "when and how" they evolved.

According to their findings, "specific genes, regulating beak development, have had to evolve to withstand the pressure of impacting their prey at a speed of up to 300 kilometres (186 miles, parenthesis mine) an hour". I've watched falcons hunt. They use their talons. I checked by watching YouTube videos. They used their talons, too, as do other hunting birds.

The researchers say "The shape of the falcon beak has also had had [sic] to evolve to be capable of tearing at the flesh of its prey” and "Evolution seems to be pushing the genome sequence in an unusual direction", but eagles, owls, kestrels and others have hooked beaks like falcons do.

What birds did the researchers use as their control? "Chickens, turkeys and zebra finches."

Regards
Mick

The first thing I checked was the date on the article to make sure it wasn’t April 1. The date was March 25, 2013, so they must be serious.

Of course, Mick is right. Anyone who has ever watched a nature video of owls, eagles, or hawks, knows that they dive almost straight down, then pull up at the last minute, fly parallel to the ground at an altitude of just a few inches for a short distance, grab the poor kangaroo rat (or other prey) with its talons, and carry the rat up and away before it knows what happened.

It is amazing that the bird can spot such a small critter at such a high altitude, and can fly with such precision at such a high speed; it is such a lucky evolutionary accident! (And, it is amazing that the photographer got the shot! But, it was probably just an accident that the photographer happened to be shooting high speed film at the time and accidentally caught the whole thing on film. )

As always, we compared what the foolish reporter wrote to what was actually published in the peer-reviewed, technical literature. The BBC Nature article quoted “Professor Mike Bruford, who authored the paper published in the journal Nature Genetics.” We found that article to see what the report really said.

Their Reasoning

The 24 co-authors of the article took the usual approach. They compared selected parts of DNA and tabulated the differences and similarities. There’s nothing wrong with that. It reveals how differences in DNA result in different physical attributes. That’s good science. We can learn from analysis like that.

The mistake they made was that they assumed all the similarities are the result of a common ancestor, and all the differences are the result of random mutation filtered by natural selection. Differences aren’t necessarily the result of random chance. There are similarities between this month’s newsletter and last month’s newsletter (both have song parodies, similar colors and font styles, etc.); but there are differences, too. The differences are the result of the editor’s conscious decisions, not random chance.

Based on their careful analysis of similarities and differences, and their erroneous assumption that differences are the result of random mutations, and a speculative assumption about mutation rates, they came up with the picture at the right showing the evolutionary relationships between various related species.

You might wonder, what is a lizard doing in this picture? The more important question is, why isn’t there a human, cow or dog in the picture?

This diagram was based on an analysis of the portion of DNA that has to do with smell.

The olfactory [smell] receptor genes of the five avian species and of green anole, human, cow and dog were annotated using GenBank, Ensembl and published data (Supplementary Note). Intact avian olfactory receptor genes were aligned using SATé-II (ref. 35), from which a neighbor-joining tree was constructed using MEGA5.03 (ref. 36), with the Poisson model chosen as the substitution model as previously analyzed. The reliability of the phylogenetic tree was evaluated with 1,000 bootstrap replicates. 1

In plain English, in addition to the olfactory genes of five bird species they compared, they compared the olfactory genes of four non-birds as a control. They expected the bird olfactory genes to be similar, and the non-birds to be different.

Sure enough, the lizard was different from the birds because they proceeded down a different evolutionary path (they believe) about 130 million years ago.

But, we wondered, what about the human, cow, and dog? Why weren’t they included as additional “proof” that the evolutionary tree is correct? Did it turn out that a cow was more closely related to a bird than a human?

Searching through the 81 pages of supplementary data, I found Table 16, which contained the total number of olfactory genes in all the species tested. Here they are. I sorted them by increasing number in the table at the right.

What should we conclude from this? That humans are more closely related to finches than dogs? Or, should we use cows instead of bloodhounds to track criminals because cows have 50% more smell genes than dogs?

We should not conclude anything at all. It simply goes to show that you can get any result you want by choosing the comparison that best confirms your bias. If they had simply compared the total number of olfactory genes, the data would have “proved” that chickens are more closely related to lizards than they are to turkeys. The only way they knew they made the “right” comparison is because it confirmed their evolutionary beliefs.

SpeciesOlfactory Genes
Saker falcon63
Peregrine falcon67
Turkey97
Lizard157
Chicken456
Zebra finch501
Human599
Dog 883
Cow1260

Defending the Paper

Let us remind you of the quote that caught Mick’s attention.

"We have been able to determine that specific genes, regulating beak development, have had to evolve to withstand the pressure of impacting their prey at a speed of up to 300 kilometres an hour," explained Professor Mike Bruford, who authored the paper published in the journal Nature Genetics. 2

There is absolutely nothing in the Nature Genetics paper that says anything at all about beaks having to withstand impact with their prey. They were comparing genes related to the sense of smell, not the strength of the beak.

Even if they had been comparing the relative strengths of beaks, the fact that one beak is stronger than another does not prove that evolution made it stronger—it could just as easily been designed to be stronger.

Rapid Evolution

The researchers claim to have found evidence for rapid evolution.

Analysis of 8,424 orthologs in both falcons, chicken, zebra finch and turkey identified consistent evidence for genome-wide rapid evolution in these raptors. 3

What they actually found were many differences. That should not be surprising because falcons are very different from turkeys and finches.

Because they are laboring under the false assumption that the differences are the result of evolution, they are surprised that there are so many more differences than their assumption of mutation rates would suggest.

They confused “differences” with “changes.” The evidence against evolution is right before their eyes; but they can’t see it.

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Footnotes:

1 Xiangjiang Zhan et al., Nature Genetics, 24 March 2013, “Peregrine and saker falcon genome sequences provide insights into evolution of a predatory lifestyle”, http://www.nature.com/ng/journal/vaop/ncurrent/full/ng.2588.html
2 Ella Davies, BBC Nature, 25 March 2013, “Falcons 'rapidly evolved' hunting skill”, http://www.bbc.co.uk/nature/21885659
3 Xiangjiang Zhan et al., Nature Genetics, 24 March 2013, “Peregrine and saker falcon genome sequences provide insights into evolution of a predatory lifestyle”, http://www.nature.com/ng/journal/vaop/ncurrent/full/ng.2588.html