As I have remarked many times, back when I was a young dinosaur enthusiast, we learned that we could never know much about the soft parts of ancient animals. Only bones and occasional imprints would be preserved in fossils, we were told.
Well, these days we are recovering many, many traces of flesh, skin, and feathers, and learning all kinds of things such as what color these ancient animals actually were. Whoa!
This winter there is yet another wonderful find, this time the skin and tissue of a Jurassic ichthyosaur. These animals visibly resemble porpoises and other whales, suggesting the results of convergent evolution toward highly optimized ocean swimmers.
The newly examined fossil contained traces of the skin and flesh of the animal, which strongly resemble the scaleless skin and blubber found in contemporary whales. As the researchers say, the resemblance to whales “resemblance is more than skin deep “ ([1], p. 1)
In contemporary animals, insulating blubber is a “a hallmark of warm-blooded marine amniotes”, so this study provides the first direct evidence that these animals were warm blooded like whales.
The fossil belongs to a type of ichthyosaur called Stenopterygius . Credit: Science Photo Library Image
Overall, the fossil remains are quite similar to contemporary whales and sea turtles. These species are only distantly related, so this is a pretty clear case of convergent evolution.
Cool!
Johan Lindgren, Peter Sjövall, Volker Thiel, Wenxia Zheng, Shosuke Ito, Kazumasa Wakamatsu, Rolf Hauff, Benjamin P. Kear, Anders Engdahl, Carl Alwmark, Mats E. Eriksson, Martin Jarenmark, Sven Sachs, Per E. Ahlberg, Federica Marone, Takeo Kuriyama, Ola Gustafsson, Per Malmberg, Aurélien Thomen, Irene Rodríguez-Meizoso, Per Uvdal, Makoto Ojika, and Mary H. Schweitzer, Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur. Nature, 2018/12/05 2018. https://doi.org/10.1038/s41586-018-0775-x
One of the coolest things about birds is their amazing color schemes. They are the prettiest animals, and they are so diverse!
This, of course, poses a challenge for biological theory. Just how could such astonishing diversity develop, and what possible function can it serve. (Being admired by me is not really much of an advantage for a bird.)
Sensei Charles Darwin, and many later theorists hypothesize that plumage, along with bird song, and other behaviors, have evolved by sexual selection. The idea is that certain features that have no other obvious survival advantage may simply be attractive to mates, and result in more breeding opportunity and success for the individual.
This theory has always been awfully hand wavy, even more than many ex post facto hypotheses about evolution. Without access to the perception and cognition of individual animals, it’s really hard to know what features are even salient, let alone preferred.
A new study this winter suggests an alternative perspective on this question [1]. The team used data about the family of Birds of Paradise from the Cornell and other collections, which have an extremely diverse, and, indeed stunning array of visual features. (At least they seem stunning and diverse to humans. Do we know what BoPs think?)
The researchers note that studying the features across this family is challenging, because they are so diverse. For example, species that are closely related should have similar features—but how do we assess “similarity”? Just as an example, should we rate the displays by color (e.g., distance in a color wheel)? Or in length and shape of feathers? Or patterns? Or all of the above?
The research approach is to broaden the “space”, to include everything that is involved in courtship displays: plumage, sounds, and behavior (dancing, nest building, etc.) And viewing the broader data, they find that many of these features form correlated complexes of features. And these complexes reduce the data, and suggest the dimensions that may be biologically relevant.
The data was broken down into (taxonomically unbounded) classes, i.e., descriptive features. In the case of ornaments, this described elements of the display. Courtship behavior was classified in specific temporal actions (e.g., “upright posture”). And sounds were statistically clustered into classes.
Together, these form a (large) feature space. Individual species were then rated on the number and diversity of features in this whole space.
“Specifically, we evaluated richness (the number of unique elements) and diversity (using an index dependent on the number and relative contribution of each element type) “ p. 3
Fig 1. Birds-of-paradise exhibit extreme diversity in colors, sounds, and behaviors used during courtship displays, necessitating novel methods to quantitatively evaluate the evolution of their complexity. (A) Sixteen exemplar species (purple tips) are shown with their phylogenetic relationships to highlight variation in plumage color, acoustic signals, and courtship display behavior. (B) Behavioral subunits were scored from field-captured videos of displaying males (S3 and S4 Tables). Behavioral subunits were combined to create composite behaviors describing any behavior across species and facilitating sliding-window analysis of behaviors and behavioral sequences. (C) UV and visual spectrum images were taken of museum specimens (S7 Table) and used to generate avian visual model-informed image stacks. Color values were clustered with respect to modeled avian discriminability, enabling whole-specimen quantification of color richness and diversity. (D) All bird-of-paradise sounds were placed into a multidimensional acoustic space defined by principal components analysis. Sounds were then given identities based on locations within acoustic space, facilitating a sliding-window analysis of sounds and acoustic sequences (S8 and S9 Tables). lws, long-wavelength sensitive; mws, medium-wavelength sensitive; sws, short-wavelength sensitive; UV, ultraviolet; uvs, ultraviolet sensitive. https://doi.org/10.1371/journal.pbio.2006962.g001
Analysis revealed correlations between color diversity and acoustic diversity and behavior diversity and acoustic diversity (though not between color diversity and acoustic diversity).
The researchers argue that these findings show “functional integration of ornamental traits into a composite unit—the “courtship phenotype.” “ (p.1) In short, BoP’s have a similar ancestral composite “courtship stuff”, which varies due to specific adaptations, such as ground versus understory courtship. Looking at “signal extremes” in plumage, for instance, is misleading, if the behavior and sounds are not taken account.
The researchers also argue that this conservation of this composite courtship stuff is evidence of strong sexual selection. Essentially, the “robust” feature space allows individual features to evolve rapidly and significantly, while conserving the overall composite signal.
Hmm. I can see that this integral composite feature space opens the way for evolutionary divergence under some kinds of selection. I’m not sure that the case for sexual selection is any stronger than others. It’s still hand waving—we don’t know what selected for diversification of these features, so let’s fall back on the explanation that “girls like that stuff”.
To be fair, the paper is careful to say that this study suggests the kinds of questions to investigate “the perceptual abilities … and psychology of signal receivers … as well as the environments through which signals are transmitted.” (p. 10) That is, the overall set of features is a composite “signal” to the females, and any sexual selection would be due to how those signals are received, perceived, and preferred.
So even if this isn’t direct evidence about purported sexual selection, it is a really useful guide to what to look for in the “signal receivers” (i.e., the “girls”).
Neat.
I’ll note that this is an excellent example of the uses of digital media archives (combined with physical specimens). It isn’t really “big data”, but it is “getting to be enough data to do something useful”.
Russell A. Ligon, Christopher D. Diaz, Janelle L. Morano, Jolyon Troscianko, Martin Stevens, Annalyse Moskeland, Timothy G. Laman, and Edwin Scholes, III, Evolution of correlated complexity in the radically different courtship signals of birds-of-paradise. PLOS Biology, 16 (11):e2006962, 2018. https://doi.org/10.1371/journal.pbio.2006962
Hot off the press: this month’s edition of the Public I includes a new article, “A New Option to Finance A Clean Energy” [1], about the new Clean Energy Credit Union.
I read Mark Rosheim’s book [3] when it came out, and loved these elegant mechanisms. How could you not love robots created by one of the most brilliant design artists known?
What’s been up to since?
Well–the Leonardo davinci robot society has been building and displaying Leonardo’s robots for all the world to see. As the web page says, “Exploring the robotic world of the Renaissance Master”.
The developers are learning how these machines are programmed, via the intricate wood disks, called “petalos” (they look very botanical).
Reverse engineering these petalos, the developers are creating design software to make it easier to create new petalos to make new drawings.
Cool!
It’s kind of cool using digital fabrication to make an analog control to make the analog drawing, rather than just digitally controlling the generation of the analog drawing (or digital drawing). (Did you follow that?)
It’s harder, but way more elegant. I’d say that the “technical coolness” multiplier is massive!
Honestly, at the prices they are charging, I’m more interested in their software, which will be an interesting intellectual “capture” of the logic of Leonardo’s design. The kickstarter doesn’t seem to say when or how the software might be released. I certainly hope it is published in some form, along with an explanation of how it works. (Robot society – call me if you want help documenting your software. It would make an interesting paper.)
Toward the end of his life, Sensei Alan Turing turned his thoughts to biological systems [2], in particular, to possible natural algorithm-like developmental processes [3]. This pioneering work is a fascinating preview of the profound effect that computational thinking would come to have on biology. Grand Master Turing glimpsed the possibilities, without knowing anywhere as much as we do about the molecular mechanisms that might implement them. (We ar not worthy!)
In his early deep vision of mechanical computing, his morphogenesis concept was crude and limited by the technology of the time. But it still seems to be valid.
This month researchers from Britain report that a Turing reaction-diffusion model describes the development of the pattern of bumps on shark’s skin. The skin of a shark has distinctive denticles, variations of which play a role in “protective armor, hydrodynamic drag reduction, feeding, and communication” ([1], p. 5)
First, the study indicates that the patterns are not random, but correspond to a reaction-diffusion process. The research followed the development of baby sharks, recording the development of their skin. They find that the denticles develop as expected from a RD model. Furthermore, the study identified an array of genes that appear to express during development in just this way.
Besides offering a possible example of a Turing RD development process, these findings are interesting in two other ways.
The key point of the Turing RD concept is that a relatively simple process can yield many different results by “tuning” parameters to the RD process. The computational simulation in this study showed exactly this feature. Retuning the simulation yielded patterns found in different species and areas of the skin. Thus, it is very possible that a single set of genes could generate a variety of different shark skins, “tuned” by other genes.
“The plasticity of this system may underlie broad variations covering the vast spectrum of vertebrate epithelial appendage patterns.” [1], p.5)
At an even deeper level, the genetic mechanisms identified in this study are present in birds, and appear to have a similar role in the development of feathers. In other words, this is a very old mechanism, shared by many vertebrates. Superficially different features such as denticles, feathers, and hair, are built on this fundamental process inherited from some long ago vertebrate. The skin of sharks, birds, and mammals are deeply similar, which makes sense because we share an ancient ancestor.
“We suggest that diverse vertebrate groups share this common, conserved patterning mechanism, before deviation in later morphogenesis gives rise to clade-specific integumentary appendages, such as denticles, feathers, and hair.” ([1], Pp6)
It is pleasing to see that Sensei Alan not only got it right, he was seeing right down into the deep core of life.
Cool.
Rory L. Cooper, Alexandre P. Thiery, Alexander G. Fletcher, Daniel J. Delbarre, Liam J. Rasch, and Gareth J. Fraser, An ancient Turing-like patterning mechanism regulates skin denticle development in sharks. Science Advances, 4 (11):eaau5484, 2018. http://advances.sciencemag.org/content/4/11/eaau5484.abstract
Andrew Hodges, Alan Turing :the enigma, New York, Simon & Schuster, 1983.
Child care for working parents is a hard problem for everyone, so it isn’t surprising that many coworking spaces do not tackle the problem. But I’m glad to see that more and more are doing so.
One reason why this is very hard is that it is really two different businesses, and you need to get both right. My general rule of thumb is to focus on being good at one thing, but that’s not an option n this case.
Mustafa reports that they designed the space from the start as “childcare with a place to work”. She comments that, “I don’t know if having a coworking space then slotting in the nursery is going to work as effectively”. I tend to agree that the childcare part is harder, and the workspace part is a lot more flexible–there are lots of ways to get the workspace right, so it is more likely that you can adapt to the childcare.
She also notes that working parents often can benefit from some psychological boost. (Moms and dads both have challenges, though not always identical or symmetric ones.) It is interesting to think of this kind of childcare+work community as an especially potent way to help both work and childrearing.
It’s hard to know if Third Door really was the first, but it certainly won’t be the last. New ones crop up every day (E.g., here, here). And locally to me, Moose International has opened an exciting new space with childcare+coworking(+food+fitness).
It seems to me that there would be advantages to having elders and kids and workers in the community. (Don’t you think having some aunties and uncles would be a real good thing?) Basically, a whole village.
“Birchwood was one of those places in which the threads of time slacked and came unstrung.” (p. 393)
This novel plays with themes about ‘threads in time’, in this case, all connected to a lovely farm house in rural England. Several generations of people are connected to each other via the house, though the connections are mostly not known to them. (You could call this “fate”, or you could call it and incredibly contrived literary device.)
Oh, and there is a ghost, too. Not that the ghost part makes the least bit of sense at all.
Over the generations, each of the characters experience love and loss, and the joy and sadness of childhood, adulthood, and death. The people are mostly pleasant, if very self-centered. Not much seems to matter beyond the immediate circle of friends and family.
Morton lavishes some attention to loving descriptions of the rural countryside, and the house, as well as Victorian art as made and as passed down. It is a pretty vision (the Pre-Raphaelites made some of the prettiest visions ever), though far from contemporary life.
In that sense, this is surely escapist fiction. The highest tech is seen in a musty old archive, and it is barely present at all. Hardly any mobile phones, most of the conversation in person or handwritten on paper (!). The real world is a vague shadow off stage. What is the archive about? Who takes care of the house? The unseen fiancée is in “banking or something”. Even the world wars are only experienced in the form of disrupted domestic lives.
The ghost story and related mysteries are told in a complicated set of flashbacks, recollections, and narratives spanning 150 years. Unfortunately, the mysteries are pretty obvious to the reader, if not to the protagonists. And much of the ‘mystery’ is due to just plain missing or hidden information. So, it’s so much a mystery as just plain lost and/or covered up.
Overall, this is a pretty well-crafted story, pleasant to read and not particularly demanding. There are some pretty images, and some sad stories here, and a not very interesting ghost.
Kate Morton, The Clockmakers’s Daughter, New York, Simon & Schuster, 2018.
