In one family of animals, this process depends on changes in the spacing of a lattice of guanine nanocrystals. Undulating displays of this process have been termed “passing clouds” and result from sequential activation of neural pathways in the satellite ganglia and anterior pedal lobes. Organs composed of glia, sheath cells, and radial fibers expand or shrink the cytoelastic sacculus to generate this process in coleoid members of a class of animals. Off-axis, U-shaped pupils may facilitate this process by maximizing a kind of “blur”; that hypothesis has supplanted the idea that this process is facilitated by undiscovered dermal opsins. Non-cephalopods that can perform this process cause it by changing the distribution of molecules like heme and melanin in cells called chromatophores. For 10 points, octopi and chameleons use pigments to rapidly undergo what camouflage mechanism? ■END■
ANSWER: skin color change [or metachrosis; prompt on crypsis; prompt on background, active, or adaptive camouflage until read by asking “what is the mechanism of camouflage?”; prompt on changing appearance or equivalents by asking “what aspect of the animal’s appearance changes?”; prompt on body patterning by asking “what aspect of body patterning?”] (The first sentence refers to chameleon skin, which has a layer of guanine nanocrystals overlaying chromatophores.)
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= Average correct buzz position