Selecting for one trait, or a small number of them, and failing to recognize that individual organisms must be integrated with their environment, leads to catastrophe, as this interview with Bill Muir explains.

Almost everyone who thought about eugenics at that time unquestionably assumed that creating a better society was a matter of selecting the most able individuals, or “hereditary genius”, as Galton put it. Against this background, consider an experiment conducted in the 1990’s by William M. Muir, Professor of Animal Sciences at Purdue University. The purpose of the experiment was to increase the egg-laying productivity of hens. The hens were housed in cages with nine hens per cage. Very simply, the most productive hen from each cage was selected to breed the next generation of hens.

If egg-laying productivity is a heritable trait, then the experiment should produce a strain of better egg layers, but that’s not what happened. Instead, the experiment produced a strain of hyper-aggressive hens, as shown in the first photograph. There are only three hens because the other six were murdered and the survivors have plucked each other in their incessant attacks. Egg productivity plummeted, even though the best egg-layers had been selected each and every generation.

The reason for this perverse outcome is easy to understand, at least in retrospect. The most productive hen in each cage was the biggest bully, who achieved her productivity by suppressing the productivity of the other hens. Bullying behavior is a heritable trait, and several generations were sufficient to produce a strain of psychopaths.

In a parallel experiment, Muir monitored the productivity of the cages and selected all of the hens from the best cages to breed the next generation of hens. The result of that experiment is shown in the second photograph. All nine hens are alive and fully feathered. Egg productivity increased 160% in only a few generations, an almost unheard of response to artificial selection in animal breeding experiments.

Weirdly, though, Muir goes on to claim that this experiment shows that capitalism is the best possible system, which just goes to show that American indoctrination is very effective. It seems to me, rather, that it shows that you can’t decide ahead of time what traits are desirable, but that they have to emerge organically in concert with other properties of the organism, and deciding ahead of time that humans must be guided by one ideology or the other is a huge mistake.

Conodonts are strange and extinct animals that left behind lots of fossils: their teeth. Practically nothing else but teeny-tiny, jagged, pointy teeth. I remember when the animals themselves were total mysteries, and no one even knew what phylum they belonged to — it was only in the 1980s that a few eel-like soft tissue fossils were found, and they were recognized as chordates (very small chordates, on the order of millimeters to centimeters long) with big eyes and membranous fins.

And now today I find two artistic reconstructions of the conodont animal that please me.

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This is kind of awesome: cephalopods only have one kind of photoreceptor, so it was thought that they would be only able to see the world in shades of gray. Those amazingly clever camouflage tricks they pull? That was just matching intensities and textures, fooling our eyes. But now someone has figured out a way they could see color, and special bonus, it also explains those funky weird pupil shapes, like you see in the cuttlefish eye to the right.

They use chromatic aberration! We think of chromatic aberration as an imaging problem — it’s caused by the fact that the degree refraction of light is partly dependent on wavelength, so the blue light in an image focuses closer to the lens than the red light. When you focus optimally on the green wavelengths, for instance, that means that the red and blue colors form an out of focus, blurry image on top of the sharp greens, producing a pattern of color fringes around objects. They jump out clearly to me when I use the cheap student microscopes here, and are why I spent a lot of extra money getting planapochromat lenses for my microscope. They have lots of corrective glass to tweak the different wavelengths into the same focal plane.

But where I see an annoyance, cephalopods evolved an opportunity. Where an object comes into sharpest focus on the eye can actually tell you what wavelengths are — so by focusing backwards and forwards on something, they can extract a rough idea of its color.

And that leads into the next nifty explanation. Where I want to minimize chromatic aberration, cephalopods want to increase it…and as it turns out, having weird off-axis apertures causes more disparity in the focal plane of different wavelengths of light, which makes it easier to discriminate color using this mechanism.

Chromatic blur and pupil geometry. The (A) full and (C) annular aperture pupils produce more chromatic blurring (CB) than (B) the small on-axis pupil, because they transmit rays with a larger ray height h. Vertical lines show best focus positions for blue, green, and red light.

It’s settled then. Cephalopods are cleverer than we are. Or maybe it’s evolution that is smarter than we are. One of those two.

Stubbs AL, Stubbs CW (2016) Spectral discrimination in color blind animals via chromatic aberration and pupil shape. Proc Natl Acad Sci U S A. 2016 Jul 5. pii: 201524578. [Epub ahead of print]

Now you’ve got another paper you can file with that dead salmon fMRI paper: one that analyzes the transcriptome, or excuse me, the thanatotranscriptome, of dead zebrafish and mice.

You should not be surprised to learn that when a multicellular organism dies, it’s not as if every single cell is abruptly extinguished: the integrated, functional activity of the individual as a whole ceases, but individual cells struggle on for a while — they’re not getting oxygen or nutrients, in a mouse they’re experiencing thermal stress as the body rapidly cools, but it takes a while for all of the cells to starve or suffocate or undergo necrosis. It seems to take a couple of days, actually. You can measure the declining amounts of RNA present in the dead animals, and yep, it looks like everything is done after a few days. This kind of study has also been done in human corpses, which show that RNA transcription continues for a couple of days.

Total mRNA abundance (arbitrary units, a.u.) by postmortem time determined using all calibrated microarray probes. A, extracted from whole zebrafish; B, extracted from brain and liver tissues of whole mice. Each datum point represents the mRNA from two organisms in the zebrafish and a single organism in the mouse.