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SO ENDS this second section on cone shell patterns. When a small blob of tissue resembling gristle which lives within a shell can generate patterns and colors of such mathematical complexity, it makes you appreciate the mental capabilities of the merest creature. That this animal can visualize and execute such a pattern on an unfolding 3D curve is further evidence. Humans have long assumed the worst of humble creatures, or simply not counted them at all. View in LinkedIn

PHYLOGENY CORRELATES. “These observations are confirmed by standard parsimony statistics and their comparison with randomized-tip null models; presence/absence of stripes, despite these being visually striking patterns used in identification, appear to lack significant phylogenetic signal in that they do not show significantly more congruence with the phylogeny than is expected under the null model in which character states have been randomly shuffled among the phylogeny tips.” https://lnkd.in/dwfZQzE View in LinkedIn

NEURAL CONTROL. “Accumulating evidence now indicates clearly that shell growth and patterning are under neural control and that shell growth and pigmentation is a neurosecretory phenomenon. Most of this evidence has been gained by detailed studies of the mantle, a tongue-like protrusion of the mollusk that wraps around the edge of the shell and deposits new shell material and pigment at the shell’s growing edge.” https://lnkd.in/d7D7yyC View in LinkedIn

WOLFRAM INSPIRATION. “Bard Ermentrout, John Campbell, and George Oster, (1986). Inspired by Wolfram and cellular automata, this is a classic. The neural hypothesis of shell patterning: the secretory activity of the epithelial cells that generate shell patterns is regulated by nervous activity. “ https://lnkd.in/dgWQqGF View in LinkedIn

UV LIGHT HISTORIES. “Unlike their modern relatives, the 4.8-6.6 million-year-old fossil cone shells often appear white and without a pattern when viewed in regular visible light. By placing these fossils under ultraviolet (UV) light, the organic matter remaining in the shells fluoresces, revealing the original coloration patterns of the once living animals. However, it remains unclear which compounds in the shell matrix are emitting light when exposed to UV rays.” https://lnkd.in/dUkV8Fr View in LinkedIn

PHYLOGENETIC SIGNAL. “We found phylogenetic signal in the continuous parameters of the primary neural network and in the presence/absence of a hidden network, suggesting that the model reasonably approximates the developmental processes underlying pigmentation patterns in the Conus species we considered. In contrast, various features of the pigmentation patterns, such as the presence of stripes and dots, do not have significant phylogenetic signal.” https://lnkd.in/dwfZQzE View in LinkedIn

NON-HOMOGENEOUS EDDIES. “The sensitivity of the neural network to perturbations means that small, gradual evolutionary shifts in one or a few parameters of the neural network can shift a shell from one pattern regime into an entirely dissimilar one.” https://lnkd.in/dwfZQzE View in LinkedIn

BIFURCATION BOUNDARIES. “This limitation does not apply to pigmentation patterns. Although the same averaging procedure is being used on each parameter of the neural-network model, it is possible, and even likely, that a set of estimated parameters will be in a region of parameter space not inhabited by any living species.” https://lnkd.in/dwfZQzE View in LinkedIn

BINARY OUTCOMES. “The role of bifurcation boundaries in evolution was recognized in earlier studies of limb morphogenesis. This feature of our results is quite different from what is usually found when inferring ancestral states of continuously variable characters. A well known limitation of methods for estimating ancestral states is that it is impossible for estimates to fall outside the range of the living species analyzed.” https://lnkd.in/dwfZQzE View in LinkedIn

STEPWISE PATTERNINGS. “The patterns generated by the neural-network model are not necessarily smooth functions of the parameter values. Instead, they can vary discontinuously when parameter values move into a different bifurcation region that produces qualitatively different patterns.” https://lnkd.in/dwfZQzE View in LinkedIn