Recently in Evolution Category

Toxicodendron radicans


Toxicodendron_radicans – poison ivy, South Boulder Creek Trail, Boulder, Colorado, July, 2015. As I was taking the picture, a little voice approached me and asked, “Do you know —? Is that —? Could that be —? Poison ivy?” Yes, and it was one of the lushest fields of poison ivy I have seen this side of New Jersey, growing right along the trail. You can identify it because it has 3 leaflets, and often the outer ones are shaped like mittens, though not as distinctively as these. Poison ivy is red only in the fall; we will see that in 2 weeks.

Evolution finally winning?


Good article in Slate, Evolution Is Finally Winning Out Over Creationism, by Rachel Gross. I have not checked the surveys myself, but Gross reports,

The people responsible for this shift are the young. According to a recent Pew Research Center report, 73 percent of American adults younger than 30 expressed some sort of belief in evolution, a jump from 61 percent in 2009, the first year in which the question was asked. The number who believed in purely secular evolution (that is, not directed by any divine power) jumped from 40 percent to a majority of 51 percent. In other words, if you ask a younger American how humans arose, you’re likely to get an answer that has nothing to do with God.


The overall proportion of Americans who believe in secular evolution has doubled since 1999, from 9 percent to 19 percent, according to a 2014 Gallup poll.…[M]ost of that increase has been drawn from the pool of Americans who previously reported that they believed in evolution guided by God [theistic evolution], which simultaneously dropped from 40 percent to 31 percent.

Why? In part because evolution is “in the air” (thank the Internet!) and in part because evolution-deniers are older and dying off.

Acknowledgment. Thanks to Mike Antolin of the Colorado State University for the link.

Typha latifolia


Typha latifolia – broad-leaved cattail, South Boulder Creek trail, 2015. The upper picture was taken with a Sony α6000 camera and a 310-mm (35-mm equivalent) lens; the lower with a Canon SX280 point-and-shoot camera and a 600-mm (equivalent) lens. Consumer Reports rated the image quality of both cameras “Very Good,” but they cautioned that you cannot compare ratings across camera types.

So I decided to compare the 2 cameras myself. The 2 images are cropped to show the same areas and reveal individual pixels. The SX280 image shows some electronic noise and a bit of chromatic aberration. The α6000 image, though taken at half the focal length, is far better. The α6000 may show better gray scale, but that may be an artifact of the exposure, which I have not compared. Nevertheless, if you do not want to push the limit, the SX280 image is very serviceable indeed.

Last March Tom English and I posted an argument here here at Panda’s Thumb analyzing an argument by William Dembski, Winston Ewert, and Robert Marks. They had made an argument that evolutionary “search” would not do better than blind search; we proved that their argument showed no such thing.

In response to our analysis here of the Dembski-Ewert-Marks paper, Winston Ewert has replied at Evolution News and Views. As that site does not allow comments, I have finally gotten around to posting a response here (six months late). Tom has now put up a related thread at The Skeptical Zone; I will try to comment in both discussions.

Ewert rather dramatically reveals that Tom and I do not actually disagree with any of the theorems in their paper. And he’s right about that. How did they discover this remarkable fact? Perhaps it was by reading our post, where we said

We’re not going to argue with the details of their mathematics, but instead concentrate on what in evolutionary biology corresponds to such a choice of a search.

or by reading a comment in that thread where I also said:

As theorems they may be mathematically true, but the average poor performance of searches is true only because so many irrelevant and downright crazy searches are included among the set of possible searches.

Ewert is right that we did not question their theorems. Instead we concentrated on what would follow from their theorems. We showed in a simple model that once there are organisms that reproduce, with genotypes that have phenotypes and fitnesses, that evolution will find higher fitnesses much more effectively than random guessing. So is it true that having what they call Active Information, embodied in a fitness surface and in a reproducing organism whose genotypes have those fitnesses, requires that there be Design Intervention to set up that system?

The issue is not the correctness of their theorems but, given that they are correct, what flows from them. Dembski, Ewert, and Marks (DEM) may object that they did not say anything about that in their paper.

We don’t think that it is a stretch to say that DEM want their audience to conclude that Design is needed.

Let’s look at what conclusions Dembski, Ewert, and Marks draw from their theorems. There is little or no discussion of this in their paper. Are they trying to persuade us that a Designer has “frontloaded” the Universe with instructions to make our present forms of life? Let’s look at what Dembski and Marks have said about that (below the fold) …


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Conjunction by Darren Insko.

Photography contest, Finalist.

Fascinating article by Rhitu Chatterjee in Science this past week. I am not a specialist in physiological optics, but I have always understood that you cannot give sight to someone who is blind from birth and is older than, perhaps, a teenager. According to Chatterjee’s article, most ophthalmologists understood the same thing. It is not true.

Chatterjee describes a project to perform cataract operations on people who are congenitally blind. Some of these are teenagers or young adults, and they learn to see – not as well as you and I, possibly because part of their visual cortex has been used for touch or hearing, but they learn to see. In consequence, a neuroscientist, Pawan Sinha, launched Project Prakash as a humanitarian effort to give sight to people who have blindness that would be preventable in the developed nations.

What interested me more, in a way, was that newly sighted people fell for precisely the same optical illusions that normally sighted people fall for. For example, the two bars across the railroad tracks in Figure 1, the Ponzo illusion, are the same length, as you can verify with a ruler. The dashed lines on the right side of Figure 1 are parallel and show that the two bars are the same length – except that the illusion persists, and the dashed lines do not look parallel.


Figure 1. Ponzo illusion. The “more distant” bar appears longer than the “closer” bar. The usual explanation, that we learn to see perspective in drawings, is apparently falsified by the fact that newly sighted people also fall for the Ponzo illusion.

Probably most readers are familiar with the Ponzo illusion. The usual explanation is that we learn over time to recognize 2-dimensional drawings of 3-dimensional objects, and we think that the upper bar is farther away than the lower bar and so must be longer.

Amazingly, 9 newly sighted children fell for the Ponzo illusion.

Likewise, Figure 2 shows the Müller-Lyer illusion. Here, (a) the line segment with the arrows pointing out always looks shorter than (b) that with the arrows pointing in. The illusion persists, even when we provide a ruler to show that the lines are the same length. (See also here for a slightly different view of the Müller-Lyer illusion.)


Figure 2. Müller-Lyer illusion. (a) The line segment with the arrows pointing out looks shorter than (b) the line segment with the arrows pointing in. The illusion persists even when we provide a ruler for reference. Newly sighted people also fall for the Müller-Lyer illusion. From M. Young, No Sense of Obligation, Science and Religion in an Impersonal Universe (2001).

Once again, the 9 newly sighted children fell for the illusion.

No one Chatterjee spoke to has a good explanation, but it seems that we must be hardwired to perceive and interpret much more than is commonly thought.

Heaven’s Peak

Heavens Peak by Jim Kocher.

Photography contest, Finalist.


Heavens Peak, Glacier Wall, and waning 3rd quarter Moon, north shore of Avalanche Lake, Sept., 1984. Oceanus Procellarum, Mare Humorum, and high-albedo Byrgius-A ray system are detectable on the Moon. Kodachrome 64.

Agrilus planipennis Fairmaire

Emerald ash borer traces, by Richard Meiss.

Photography contest, Finalist.


Larval feeding galleries of Agrilus planipennis Fairmaire – emerald ash borer. They are an invasive species in the American Upper Midwest (arriving here from Asia some fifteen years ago) that poses a serious threat to the native population of ash trees (genus Fraxinus). Some of their opportunistic enemies (e.g., woodpeckers and squirrels) inflict their own damage on the trees as they search for the larvae. Their spread is aided by human transport of infected wood, especially as firewood.

Partial eclipse of the sun


Partial eclipse of the sun by Marilyn Susek.

Photography Contest, Finalist.

Susek.Parcial_Solar_Eclips_March_3rd_2015 (600x450).jpg

Partial eclipse of the Sun, Ravenfield, Rotherham, S. Yorks., UK.

New hominin species discovered


And Science has just posted an interesting piece by Ann Gibbons, describing how the principal investigator, paleoanthropologist Lee Berger, advertised first for “tiny and small, specialised cavers and spelunkers with excellent archaeological, palaeontological and excavation skills” and later for “early career scientists” to come to Johannesburg and study the fossils. Gibbons reports that there was a certain amount of grumbling over Berger’s approach. The approach, however, apparently paid off: Gibbons and his team have discovered a new hominin, Homo naledi.


The fossils have not yet been dated, but Science reports that they display a round skull but a small brain, a wrist that suggests toolmaking, fingers that suggest tree climbing, and a foot that suggests upright walking. The Times article here quotes Ian Tattersall of the American Museum of Natural History to the effect that it is certainly a new species, but possibly not of the genus Homo. You may find a technical article here in the open-access journal eLIFE.

Berger’s team, which seems to number about 50, will now set about dating the fossils and trying to extract DNA. To these ends, Gibbons reports that Berger will attempt to recruit yet more young scientists.

Not to be outdone, Ken Ham of Answers in Genesis reports that his colleague Elizabeth Mitchell is working on an article on Berger’s discovery. Ham adds,

But we can say with confidence that this discovery changes nothing about our understanding of human history.

Truer words were never spoken.

The September issue of Natural History magazine is devoted almost entirely to essays concerning Alfred Russel Wallace. I usually turn the pages of NH, look at the pictures, and read many of the captions – but I read this issue almost in its entirety (and therefore cannot resist writing about it). Unfortunately, it looks as though none of the articles is available on the Web, but you can get your own copy for $3.95 (US), presumably on the newsstand.

The issue was edited by Richard Milner, head of the Wallace Centenary Celebration. According to the second comment below, he also edited a special issue of Skeptic magazine, and you may request a free copy of either or both magazines by writing Mr. Milner an e-mail.

The first article, by the distinguished naturalist David Attenborough, outlines Wallace’s career. I did not know that, as Wallace returned from South America, his ship caught fire, and he lost all his notes and his specimens; I think I learned that fact 2 more times in subsequent articles. Attenborough outlines how Wallace got the idea of natural selection while studying birds of paradise. As is widely known, he sent an essay to Darwin. Lyell and Hooker arranged to have Wallace’s paper presented alongside a paper by Darwin, who then rushed his own book, On the Origin of Species, into print. Attenborough remarks, “You might have thought there was an embarrassment or perhaps hostility or resentment” between Darwin and Wallace. “Not at all. The two men had great respect for each other, untinged by any sign of jealousy.”

An article by geneticist Andrew Berry goes over some of the same material, though in more detail and more biographically. Berry observes that Wallace’s 1865 definition of “species” is identical to the “biological species concept” that is usually attributed to Ernst Mayr 80 or so years later. There is a certain amount of redundancy in these articles, each of which was written as if the authors thought they would have to stand alone: Berry introduces us to Wallace’s Line, apparently unaware that Attenborough has already done so in the preceding article and Gary Noel Ross will do so later. Wallace originally went abroad, says naturalist Errol Fuller, to earn money by supplying stuffed animals to middle- and upper-class England; evidently such products were in considerable demand at the time, and Attenborough estimates that Wallace collected 110,000 insects, 7500 shells, 8050 bird skins, and over 400 mammals and reptiles. Fuller shows us some stuffed specimens that remain in remarkably good condition today.

But for someone who just wants to look at the pictures, the high point of the issue might be a series of photographs of birds of paradise by Tim Laman with a narrative by Edwin Scholes. An article by Ross describes (sort of) following in Wallace’s footsteps and searching for the golden birdwing butterfly; this article likewise displays excellent photographs, some by the author and including what seems to be a selfie taken from a distance of several meters.

The final article is a reprint of a 1980 article by Stephen Jay Gould. Gould discusses the fact, noted in an earlier article as well, that Wallace and Darwin disagreed on sexual selection, and also on the origin of the human brain. Wallace, according to Gould, took the “hyperselectionist” position that everything that evolved is an adaptation. The brain, however, can do much that it is not adapted to do, like write symphonies. Such reasoning, says Gould, leads Wallace “right back to the basic belief of an earlier creationism that it [Wallace’s hyperselectionism] meant to replace—a faith in the rightness of things, a definite place for each object in an integrated whole.”

If you want to know more, I am afraid that you will have to buy the magazine. And cheer up! The pictures are better in print than on your monitor.

Felis catus


Photograph by Andrey Pavlov.

Photography contest, Finalist.


Felis catus – domesticated cat. Mr. Pavlov tells us, “The photo of the cat is my cat Rosie, short for Rosen of Einstein-Podolsky-Rosen (her sister is named Electron, not pictured). She is a daughter of a feral cat, rescued from a swamp in central Louisiana.”

Eumorpha achemon


Photograph by Gabrielle Hovinen.


Eumorpha achemon – achemon sphinx moth.

Noncircular pupils explained


Several years ago, I reviewed the book Evolution’s Witness: How Eyes Evolved, by Ivan Schwab. The book is downright encyclopedic, and I could not praise it highly enough. But in my review I wondered about elongated pupils, such as those of a cat, which are barely discussed the book. I remember reading somewhere that the elongated pupil could be stopped down farther than a circular pupil, but that explanation does not account for the problem that horizontal structures will be more clearly resolved than vertical structures (presuming that the pupil is elongated vertically and the eye is nearly diffraction limited).

A team from Berkeley and Durham University now proposes a better explanation. Without going into detail, they find that predators that ambush their prey, like cats, typically have vertically elongated pupils. From the abstract:

Vertically elongated pupils create astigmatic depth of field such that images of vertical contours nearer or farther than the distance to which the eye is focused are sharp, whereas images of horizontal contours at different distances are blurred. This is advantageous for ambush predators to use stereopsis to estimate distances of vertical contours and defocus blur to estimate distances of horizontal contours.

One way to put it: All the blur due to defocus is in the vertical direction, so horizontal contours are blurred when defocused, whereas vertical contours are not, because the blur is parallel to the contour; see their Figure 2(A). I do not want to go into detail, but they demonstrate that ambush predators, like the cat, that prowl close to the ground benefit from having good stereo vision for vertical contours. Prey animals, like the goat, often have horizontal pupils, which supposedly facilitate wide-angle views. Curiously, their pupils remain horizontal regardless of the orientation of their heads.

This paper goes a long way toward explaining why different animals have differently oriented pupils. You may see a video and a short article here and an NPR report here.

The paper does not explain how, when I was an elongating pupil in fourth grade, my teacher, an ambush predator if ever there was one, managed to see through 360°.

Who? The Chevalier de Lamarck, that’s who. Born 1 August 1744, he was the first evolutionary biologist who gave a mechanism that could, in principle, explain adaptation. Even though his mechanism was wrong, he was a true pioneer and a great biologist. (I’ll leave this post short, so as not to push Matt’s photo contest off the page).

Actias luna

Photograph by Tom Gillespie.

Photography Contest, Second Place.


Actias luna – Luna moth, Duluth, Georgia. Shot from underneath, as it was resting upside-down in my azalea bush.

Domesticated: Book review


A number of years ago, I found a family of raccoons living in my chimney.1 I got them out by dropping a trouble light down the flue and turning it on for a few days. According to Richard C. Francis, in his splendid book, Domesticated, animals such as raccoons living in urbanized areas represent the first step toward domesticating those animals.

The full title of the book is Domesticated: Evolution in a Man-Made World, and Francis shows in considerable detail how various animals became domesticated: dogs, cats, pigs, sheep and goats, reindeer, camels, horses, rodents, and perhaps humans, as well as other predators such as raccoons and ferrets. Each scenario is slightly different, each seems well documented, and each has just a little bit of just-so story in it.

Melting of polar ice


Photograph by Dan Moore.

Photography Contest VII: Winner.


Melting of polar ice. Mr. Moore writes, “Our ship got caught in the ice and had to be freed by a Canadian ice breaker. Global warming – what?? Actually, yes – we could not get through because so much ice broke free further north near the polar ice cap and was blown south into the shipping channels.” Mr. Moore will receive a signed copy of Why Evolution Works (and Creationism Fails), which has been donated by one of the authors.

Here are the finalists of the 2015 photography contest. We received 16 photographs from 7 photographers, somewhat fewer than in previous years. This year we decided to choose 1 picture from each entrant and enlisted our wife to help with the choices. The text was written by the photographers and lightly edited for consistency.

The finalists are given below the proverbial fold, in alphabetical order of last name. Please look through their photographs before voting for your favorite. You will have to be logged in to vote on the poll. We know it is possible to game these polls. Please be responsible and vote only once. If we think that the results are invalid, we will cancel the contest.

Polling will close Friday, July 17, at approximately 12:00 CST.

Reed Cartwright contributed to this post.

Zenaida macroura


Zenaida macroura – mourning dove, Walden Ponds Wildlife Habitat, Boulder, Colorado, spring, 2015. I have not seen nor heard a mourning dove within the city limits since the collared doves took over.

Photography contest finalists next week, July 6, noon, CST.

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