I found this spider inside the house the other day and managed to get a picture showing the 8 eyes. In case you were wondering what it is like to be a bat, think about what it must be like to be a spider.
Spiders have simple eyes, as opposed to compound eyes like those of a dragonfly. Because the eyes are so small, they cannot have good resolution: Even if the eyes were diffraction-limited, their sensors would have to be roughly the same size as the cones in human eyes, for example, and there would be many fewer of them. (In photographic terms, all diffraction-limited F/4 lenses have the same resolution limit, but a longer focal-length lens affords more detail. This paper by Haldane notes that an eye is not very good until it reaches a certain size, but a colleague of mine has just pointed out that context matters and the spider does not need a better eye.)
According to the Wikipedia entry on spider vision , the two central eyes in the lower bank are the principal eyes, and they do their best to form an image, but the pixels (if you will) are nowhere near the focal point. The spider is thus dreadfully nearsighted, though he must get some imaging due to the depth of field. The other, secondary eyes are used for light and motion detection, and, for example, polarization detection.
President Biden bumps fists with NIH Director Dr. Francis Collins during a visit to the NIH campus on December 2, 2021. I found it interesting that they were both wearing masks and they did not shake hands. Credit: NIH/Chia-Chi Charlie Chang. Work of the United States government, not subject to copyright.
I am a little late out of the starting blocks, but last Sunday Francis Collins published an opinion article titled Take It From a Scientist. Facts Matter, and They Don’t Care How You Feel in the opinion section of The New York Times. In case there are any readers who do not know it, Francis Collins is the former director of the Human Genome Project and more recently director of the National Institutes of Health. He presided over NIH in the early part of the pandemic and during the development of vaccines for Covid.
In the article, he outlines the development of the vaccines and rightly bemoans the number of Americans who refused to get vaccinated, even when vaccination was free. He notes that white evangelical Christians, of whom he is one, were the most highly resistant to getting vaccinated. He says,
William Jennings Bryan (left, seated) being questioned by Clarence Darrow at the Scopes Trial in Dayton, Tennessee. Image from the Smithsonian Archives via Wikimedia.
Glenn Branch is deputy director of the National Center for Science Education, a nonprofit organization that defends the integrity of American science education against ideological interference. He is the author of numerous articles on evolution education and climate education, and obstacles to them, in such publications as Scientific American, American Educator, The American Biology Teacher, and the Annual Review of Genomics and Human Genetics, and the co-editor, with Eugenie C. Scott, of Not in Our Classrooms: Why Intelligent Design is Wrong for Our Schools (2006). He received the Evolution Education Award for 2020 from the National Association of Biology Teachers.
In the summer of 1925, a young teacher, John T. Scopes, was on trial in Dayton, Tennessee, for violating a recently enacted state law, the Butler Act, which forbade educators in the state’s public schools to “teach any theory that denies the truth of the Divine Creation of man as taught in the Bible, and to teach instead that man has descended from a lower order of animals.” The Scopes trial was instantly a national sensation, partly thanks to the participation of two national figures — William Jennings Bryan on the prosecution team and Clarence Darrow on the defense team — and the reportage of a third, the brilliant but mordant journalist H. L. Mencken. With its hundredth anniversary just around the corner, the Scopes trial is understandably attracting attention again, with recent treatments including Randy Moore’s The Scopes “Monkey Trial” (2022), Gregg Jarrett’s The Trial of the Century (2023), and Brenda Wineapple’s Keeping the Faith (2024). These are all more or less readable and accurate guides to the context, personalities, conduct, aftermath, and significance of the trial. And then, in contrast, there is Jerry Bergman’s The Other Side of the Scopes Monkey Trial (2023).
What is the thesis of The Other Side of the Scopes Monkey Trial? According to its subtitle, At Its Heart the Trial was about Racism, while within the text, Bergman awkwardly declaims, “The trial was about human evolution, and more about racism and eugenics than religion and evolution” (p. 5, emphasis in original). Later, a section complaining that commentators on the trial ignore the racism and eugenics of both classroom textbooks and the American scientific community of the 1920s is entitled “Denying the Core of the Scopes Trial”; in the following chapter, Bergman writes, “That the teaching of eugenics was at issue in the Scopes Trial was obvious to those who understood what eugenics is all about is clear” (p. 61); and the chapter after that is entitled “The Scopes Trial: A Struggle Against Eugenics and Racism.” And in the final chapter, Bergman concludes, “The racism and eugenics that was central in the Scopes Trial has been ignored, even though it is a well-documented part of the record” (p. 195). Thus, although there is a certain perplexing vacillation between racism and eugenics, the book’s thesis appears to be that the Scopes trial was about these issues.
Partial lunar eclipse as seen from Boulder, Colorado, approximately 8:40 local time, yesterday. Also a supermoon, but it was hard to tell with the naked eye. Not the best display ever, yet for some reason eclipses fascinate.
Araneus gemmoides – female cat-faced orb weaver. The abdomen is over 1 cm long. The photograph is upside down to emphasize the "ears" and the "eyes."
The underside of the spider is displayed below the fold.
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