Recently in Evolution Category

Phalacrocorax harrisi

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Photograph by Dan Moore.

Photography contest, Second Place.

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Phalacrocorax harrisi – flightless Galápagos cormorant. Mr. Moore writes, “Having made its way to a small set of islands we now call the Galápagos and given sufficient food and no predators, the cormorant had no need to fly, so over the years lost its full-feathered wings. Its bright-orange companion is Grapsus grapsus – the Sally Lightfoot crab.”

A big story in the press today. Scientists – mechanical engineers and physicists, one working for Boeing with his office only a few miles from my home – show that the evolution of airplanes works the same way as the evolution of organisms:

The evolution of airplanes

A. Bejan, J. D. Charles and S. Lorente

J. Appl. Phys. 116, 044901 (2014);

http://dx.doi.org/10.1063/1.4886855

(fortunately this paper can be downloaded for free).

They make allometric plots of features of new airplane models, log-log plots over many orders of magnitude. The airplanes show allometry: did you know that a 20-foot-long airplane won’t have 100-foot-long wings? That you need more fuel to carry a bigger load?

But permit me a curmudgeonly point: This paper would have been rejected in any evolutionary biology journal. Most of its central citations to biological allometry are to 1980s papers on allometry that failed to take the the phylogeny of the organisms into account. The points plotted in those old papers are thus not independently sampled, a requirement of the statistics used. (More precisely, their error residuals are correlated). Furthermore, cultural artifacts such as airplanes do not necessarily have a phylogeny, as they can borrow features from each other in massive “horizontal meme transfer”. In either case, phylogeny or genealogical network, statistical analysis requires us to understand whether the points plotted are independent.

The paper has impressive graphs that seem to show trends. But looking more closely we notice that neither axis is actually time. If I interpreted the graphs as trends, I would conclude that birds are getting bigger and bigger, and that nobody is introducing new models of small airplanes.

At least we may rejoice that the authors are not overly shy. They make dramatic statements on the implications for biology:

The engine mass is proportional to the body size: this scaling is analogous to animal design, where the mass of the motive organs (muscle, heart, lung) is proportional to the body size. Large or small, airplanes exhibit a proportionality between wing span and fuselage length, and between fuel load and body size. The animal-design counterparts of these features are evident. The view that emerges is that the evolution phenomenon is broader than biological evolution. The evolution of technology, river basins, and animal design is one phenomenon, and it belongs in physics.

and

Evolution means a flow organization (design) that changes over time.

Thanks, now I finally know what evolution is. And that biologists should go home and leave its study to the physicists and engineers.

[Note: I will pa-troll the comments as aggressively as I can and send trolling and troll-chasing to the Bathroom Wall.]

Contrails

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Contrails, in the general direction of Denver International Airport, as seen from Boulder, Colorado, August, 2011. Jeff Mitton, Professor of Ecology and Evolutionary Biology at the University of Colorado, in an article in the Boulder Daily Camera, reminds us that contrails reduce diurnal temperature fluctuations and may have a significant effect on climate.

By David MacMillan.

8. New perspective. I think there are several different varieties of creationism activists. Some are obsessed with the presumed negative effects of evolution and secular humanism. Some are driven by suspicion for science and the certainty that a conspiracy must be afoot. Some use creationist apologetics to make themselves feel smarter and better-informed than the general public. Some are genuinely interested in science and want to know the truth.

I’d be lying if I said my motivations for arguing creationism were firmly in the last camp. I wasn’t much of a conspiracy theorist, but I certainly believed that there were inevitable negative consequences from the acceptance of evolution. I was definitely stuck-up about my “special” expertise. But deep down, I really did want to know the truth about the world. I loved being right, but I loved learning new things more.

Acharia stimulea

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Photograph by Al Denelsbeck.

Photography contest, Winner.

Our congratulations to Al Denelsbeck, the winner of the latest Panda’s Thumb photography contest with his remarkable photograph “Parasitized moth larva.” “Flightless cormorant,” by Dan Moore, was second. We will award Mr. Deneslbeck a book generously supplied by NCSE.

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Acharia stimulea – saddleback caterpillar moth larva, which has been parasitized by a species of Braconid wasp, of the superfamily Ichneumonoidea. Mr. Denelsbeck writes, “Darwin, of course, made a comment in a letter to a colleague regarding the nasty life cycle of the Ichneumon family. The wasp has laid eggs in either the caterpillar itself, or in the eggs that would hatch the caterpillar, and the wasp’s larva hatched and commenced eating the caterpillar from the inside. Seen here, the larva have come to the surface and spun their cocoons outside the caterpillar’s body to pupate within, soon to emerge outside as adults. The caterpillar, already ravaged internally, will live only a few more days.

“Also of note is the normal appearance of the caterpillar, an example of aposematic coloration, or ‘keepaway’ signals. The spikes are assisted by a significant irritant, and the combination of the two traits serves to protect the caterpillar from predators such as birds; the irritant chases them off, while the coloration is memorable enough to form the association in the unlucky bird’s mind so they will not make another attempt on any member of the species. This mechanism, however, doesn’t impress the wasps.”

By David MacMillan.

7. The religion of evolution.

The final set of creationist misconceptions about evolution surrounds its supposed religious, moral, and ethical implications. These objections prove difficult to address, simply because they have little or no objective basis and are almost purely philosophical or religious. This section will concentrate mostly on explaining the relationships and connections between these arguments, as systematically refuting them would delve deep into philosophy and theology and is far beyond the scope of a single post.

Opposable thumb

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Photograph by Helena Insko.

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Opposable thumb. Ms. Insko submits this photograph of a fully opposable thumb as evidence of evolution and writes, “My mom and I have been voting in the photo contest as long as I can remember (I’m 10). When my mom told me the theme was how we know evolution is correct, this is my answer (and my hand).”

By David MacMillan.

6. Genetic evidence.

Revised July 4, 2014.

Perhaps one of the clearest and most obvious confirmations of evolution is the convergence between the evolutionary paths of descent determined by fossil evidence and the phylogenetic tree generated by algorithms analyzing genetic information. Because the tree of universal common descent is real, not invented, it leaves the same fingerprint in every part of nature that life touches. Matching trees can be found in global fossil distribution, in analysis of skeletal morphologies, in chromosome length, count, and banding, and in numerous common genetic sequences.

Not every genetic sequence yields a perfect branching tree. Evolutionary theory would not predict perfect branching trees, because random mutations scramble the relationships over time. Even though mutations provide the variation needed for diversification, their accumulation throughout that diversification can eventually obscure the evidence needed to reconstruct those relationships.

A follow-up on the Nye-Ham debate in the Reports of the National Center for Science Education: Andrew J. Petto said it wasn’t a real debate, which is sort of true, but the most interesting observations, to me, were those made by John W. Patterson. Prof. Patterson, an engineering professor, correctly gives Ken Ham credit for not obfuscating, for not pretending that creationism is based on anything but his interpretation of the Bible. He thinks that other creationists may fault Mr. Ham for his candor, but he argues that

there will be far less public confusion about the distinctions between legitimate evidence-based science and the faith-based biblical varieties so successfully propounded by creationist debaters. In contrast, Ham’s approach lays bare what’s really behind all creationism, from the young-Earth biblical literalism to the more inchoate ‘intelligent design’ models.

Photo Contest VI: Finalists

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Here are the finalists of the 2014 photography contest. We received approximately 24 photographs from 10 photographers, somewhat fewer than in previous years. Most of the pictures were excellent, and we had to enlist our wife to help narrow the number of finalists to 5.

To choose the finalists, we considered what we thought were the scientific and pictorial qualities of the photographs, and also attempted to represent as many photographers and present as much variety as possible. 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 11, at approximately 12:00 CST.

Reed Cartwright contributed to this post.

By David MacMillan.

5. Evolution of evolution.

Most creationists believe that the theory of evolution was developed out of an ideological commitment to explaining life apart from God. Explanations of the history of evolutionary theory often point out personal struggles in the lives of prominent scientists – Darwin most often, of course – in support of this belief. “Secular scientists wanted a way of explaining a world that didn’t require God, so they invented this ridiculous theory.” To creationists, this foundation offers an easy way of dismissing all the theoretical and observational bases of evolution. If evolution is just wishful thinking born of anti-theistic extremism, then all the “evidence” is reduced to ad hoc speculation.

Because of this misconception, creationists rarely understand the actual history of how geology, paleontology, and biology built upon each other to provide us with our understanding of the world. Mainstream geology emerged significantly ahead of Darwin’s work; many early geologists were Christians. Studying the distribution of rock layers around the globe allowed geologists to construct a complete geologic column and begin appreciating the incredible amount of time the column represents. Moreover, the regular progression of extinct species fossilized throughout the geologic column had been well-catalogued.

Pan troglodytes

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Photograph by Gerry L.

Photography contest, Honorable Mention.

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Pan troglodytes – common chimpanzee.

By David MacMillan.

4. Transitional fossils.

One of the most common and most frustrating creationist objections to evolution is the claim that there are no “missing links” or “transitional fossils” required by evolution. This claim is made without qualification, particularly in presentations to lay or church audiences. As unthinkable as it might seem, creationists really do believe that transitional fossils simply do not exist. On this basis, they conclude that evolution must be false.

They maintain this completely erroneous view by consistently misrepresenting what a transitional fossil actually is. Creationists don’t deny that Archaeopteryx, Pakicetus, Tiktaalik, Australopithecus, and similar prominent examples of transitional fossils exist; they rather argue that these are not “true” transitional fossils.

si-JulAug2014.jpg I’ve a brief new article in the new Skeptical Inquirer (July/August 2014) regarding Casey Luskin’s botched attack on the second episode of Cosmos. Here it follows - your comments are welcomed.

Fox TV’s Seth McFarlane has joined with astrophysicist Neil deGrasse Tyson and Ann Druyan, Carl Sagan’s widow and collaborator, to continue Sagan’s marvelous Cosmos series of decades ago. The new series is a splendid blend of homage to Sagan’s original one with dazzling new graphics–and new discoveries.

The second episode of the series, first broadcast March 16, 2014, covered evolution and natural selection. (Link) As expected, creationists were furious. The main promoter of “intelligent design,” Seattle’s Discovery Institute, has run several anti-Cosmos blogs on its Evolution News and Views (ENV) website.

In their zeal to attack Tyson and the Cosmos series, however, the Discovery Institute has created a stunning example of the straw man logical fallacy. This fallacy is so named because it involves attacking one’s opponent not by an honest dissection of his or her actual views but by attacking a caricature, a distorted misrepresentation of those views. The Discovery Institute’s attack on the evolution episode of Cosmos was a particularly egregious example of this fallacy–a straw man for the ages, as it were.

Recurvirostra americana

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Recurvirostra americana – American avocet, Walden Ponds, Boulder, Colorado.

By David MacMillan.

3. You don’t evolve, your species does.

Creationists often conceptualize evolution as something which is purely vertical: successive changes from parent to child to grandchild to great-grandchild accumulating over time. They can hardly be faulted for this misconception, because this view seems to be shared by the general public and even reinforced by the sometimes-imprecise explanations and depictions of evolution by museums and science educators.

Evolutionary adaptation, however, does not happen in a straight line from parent to child. Rather, adaptation takes place throughout a population as different genetic sequences spread outward from parents to all their offspring and are recombined and reshuffled in many different individuals each successive generation. Evolution is wibbly-wobbly, timey-wimey stuff. It is the combination of changing genetic material across an entire population that makes major evolutionary adaptation possible; without this constant mixing and recombination from the entire population, evolution would grind almost to a halt. Evolution is a phenomenon that functions not at the level of the individual, nor at the level of individual lineages, but across the entire population within the species (Figure 1).

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Figure 1. This hypothetical example depicts evolutionary change as an emergent property of the entire population. Both the “ABC” combinations (in shades of blue) and the “XYZ” combinations (in shades of red) offer a survival advantage and are passed on, while combinations of the two (shown in shades of purple) are detrimental and are removed from the population. No specific mutation order is required; as long as the selection pressure remains steady, the mutations accumulate together (essentially “finding” each other) and two separate genotypes emerge.

Anas cyanoptera

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Anas cyanoptera – cinnamon teal, Walden Ponds, Boulder, Colorado.

By David MacMillan

2. Variation and adaptation

The majority of modern creation science freely admits the existence of biological variation, adaptation, and speciation. Indeed, the recent-creation model – particularly the belief that all extant life descended from a small group of “kinds” present on Noah’s Ark which diversified into all families on Earth after a global flood – requires enormous adaptive variation and near-constant speciation. Creationists estimate that fewer than 10,000 pairs of land-dwelling, air-breathing animals on the Ark diversified to represent all families alive today. There are around 6.5 million land-dwelling species today, so millions of speciation events would have needed to take place over the past 44 centuries since their global flood.

Photography Contest, VI

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Kodak Precision Enlarger, Model 1.



Note added June 16 at approximately 1:10 CST: Submission period extended 1 week to June 23.

Polish your lenses, oil your tripods, search your archives – the sixth Panda’s Thumb photography contest, begins – now!

We will accept entries from 12:00 CST, June 2, through 12:00 CST, June 16 June 23.

The theme of the contest is History of Evolution, by which we mean photographs of fruit flies, barnacles, pea plants; fossils, stromatolites; geological formations; anything related to how we know or have deduced common descent. Entries submitted under this category should include a line or two explaining how or why the photograph relates to the history of evolution.

Additionally, we encourage entries in a second, General category, which includes pictures of just about anything of scientific interest. If we get enough entries, consistently with Rules 11 and 12, we may divide either category and award additional prizes, presuming, of course, that we can find more prizes.

The winners will each receive a book generously donated by the National Center for Science Education.

Geum aleppicum

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Photograph by Andrew Freeman.

Photography contest, Honorable Mention.

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Geum aleppicum – yellow avens, Pearl Lake, Colorado.

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This page is an archive of recent entries in the Evolution category.

Eugenics is the previous category.

Evolution Education is the next category.

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