Rattus sp.

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Rats
Rattus sp. – rat.

These rats, probably Norway rats (see link), are active during the day, unlike most rats, which are nocturnal. The rat that interested me was the rat with the white blotch. Domesticated animals such as horses, cows, dogs, and now foxes often show blotchy coats, whereas, as far as I know, wild animals do not. The blotched rat, then, is probably a feral rat or a descendant of a feral rat that bred with a wild rat. Is that right? Did someone irresponsibly release a domesticated rat into the neighborhood?

Act of God?

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Landslide
United States District Court, Eastern District of Kentucky

Is God wroth with the Ark Encounter? We cannot know for sure, but it is entirely possible that he or she visited an admittedly minor act of God upon Ark Encounter LLC. The insurers of Ark Encounter LLC, all six of them, may or may not have thought so, but they refused to pay for a landslide along a road leading directly to the “Ark.” Ark Encounter, in its turn, prayed for relief, not to God, but to the United States District Court (see the link in the caption).

Dan Phelps, a nearby Kentucky geologist, notes, “Any competent geologist would have told them that landslides are a consequence of building on the shales of the Kope Formation,” and expresses surprise that they did not have access to one. He further explains that the photograph, which we got from the text of the lawsuit, “is a textbook example of a landslide occurring in the Late Ordovician Kope Formation of northern Kentucky. The Kope is typically more than 50% shale. If the Kope gets wet and is on a steep slope, it is very much vulnerable to landslides.”

It seems likely that Ark Encounter’s geologists are no better than their staff astrophysicists, though their failure is perhaps more obvious and more meaningful.

Up from creationism

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Galaxy
http://chandra.harvard.edu/photo/2014/eso137/. Photo credits (it is a composite): X-ray: NASA/CXC/UAH/M.Sun et al; Optical: NASA, ESA, & the Hubble Heritage Team (STScI/AURA).

Our occasional contributor (and my sometime pen pal) David MacMillan has written a splendid article detailing his “conversion” from young-earth creationist to rational scientist. I will not give the story away, but Mr. MacMillan seeks answers from distinguished “creation scientists” and accepts complex rationalizations, until he sees an event that obviously took much, much longer than 6000 years to unfold.

Damnedest eye I have ever seen

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Eye cross section
Eye of Diretmus argenteus – silver spiny fish. Modified Figure S9 of Supplementary Materials for "Vision using multiple distinct rod opsins in deep-sea fishes".

The figure represents the eye of the silver spiny fish, Diretmus argenteus. Elizabeth Pennisi reports in Science magazine that this fish lives in the very deep ocean, where there is no ambient light from the sun. Unlike many other creatures, such as blind cave fish, that lose their sight when deprived of light, these fish have evolved an eye that detects the faint glow of bioluminescence.

And what an eye it is! It consists of a cornea, a ball lens, an iris that is probably fixed and functions only as an aperture stop, and a variety of rods that apparently can distinguish color. Layers of rods are piled on top of each other. In the upper part of the drawing, the long rods are 95 μm long, and the short rods in the stack are each 15 μm long. The lower part of the drawing shows a layer of ultra-long rods 525 μm long and a stack of short rods 27.5 μm long. The rods contain different photopigments, or opsins, and span the range of bioluminescence wavelengths. Presumably the lengths of the rods also have something to do with color sensitivity. There is also a layer of cones, but I will hazard the guess that they are nonfunctional, since cones are generally used in bright, or photopic, illumination. It is unusual that the rods, which are used in dim, or scotopic, illumination have evolved to distinguish colors. I do not know what the honeycombed area represents, but it is probably various retinal layers that are not light-sensitive.

The optics of the eye is also interesting. The bulk of the receptors appear in the upper and lower parts of the picture, not along what you might think of as the axis, so the fish sees primarily above and below. I will hazard another guess, that the index of refraction of the liquid inside the eye is close to that of water, so the cornea is weak, and most of the power is due to the ball lens. I do not know whether the lens actually projects an image or merely acts as a condenser; see the Appendix.

The original paper is Vision using multiple distinct rod opsins in deep-sea fishes, by Zuzana Musilova and 17 others. The paper is concerned primarily with the evolution of the opsins, not the structure of the eye.

David Gelernter gives up on Darwin

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On the thread about Eric Holloway’s dismissal of criticisms of ID, a commenter, “camsail”, asks whether people have a response to an article in the conservative online magazine Claremont Review of Books by Yale University computer scientist and contrarian David Gelernter. This thread is intended to allow discussion of that article without disrupting the Eric Holloway thread. Let’s take a look …