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Today we have the first part of a series of photos taken at Down House, where Darwin lived most of his life. The photographer is Neil K. Dawe, who lives on Vancouver Island, British Columbia. Neil’s captions and IDs are indented, and you can enlarge his photos by clicking on them.

Down House, Kent, UK

On our UK trip this past June, we stopped at a special place, Down House, where we spent some time wandering through the home and grounds of Charles Darwin. The house has been carefully preserved and we spent some time on the upper floor, essentially an exhibition of his life. There we saw a number of Darwin artifacts such as some of the equipment and reference books he took with him on the Beagle voyage, some of his notebooks, as well as manuscript pages from On the Origin of Species.

Darwin purchased the house on 22 July 1842 for £2,200 and moved in that September. He described it as “… a good, very ugly house with 18 acres, situated on a chalk flat, 560 feet above sea. There are peeps of far distant country and the scenery is moderately pretty: its chief merit is its extreme rurality. I think I was never in a more perfectly quiet country”:

The downstairs includes a number of rooms that are laid out much as Darwin and Emma, his wife, had left them, including Darwin’s study, where he wrote On the Origin of Species. We walked through the study, which has been restored to the original 1870s arrangement with original furniture and many of Darwin’s possessions. Since photographs are not allowed in the home I have included the following image of his study by Anthonyeatworld, via Wikimedia Commons, licensed under CC BY-SA 3.0, Cropped from the original:

Later, we wandered through the estate gardens to visit the vegetable garden (on the right of the photo) and Darwin’s greenhouse and cloches where he conducted many of his experiments. After completing construction of the heated greenhouse, Darwin requested plants from Kew Gardens and upon their arrival he notes in a letter to J.D. Hooker, “I am fairly astounded at their number! why my hot-house is almost full!. . . I have not yet even looked out their names; but I can see several things which I wished for, but which I did not like to ask for.”:

The greenhouse, where Darwin carried out many of his experiments, was fully stocked during our visit:

A Pitcher Plant (likely Nepenthes spp.) in the greenhouse; Nepenthes was included in a list of nursery plants Darwin planned to purchase:

Another greenhouse plant, an orchid, likely from the genus Lycaste:

We then wended our way over to the Sandwalk. Darwin leased 1.5 acres in 1846 from Sir John Lubbock, planted it with hazel, birch, privet, and dogwood, and created the gravel path. Francis Darwin recalled that “The Sand-walk was our play-ground as children, and here we continually saw my father as he walked round.” Huxley also spoke of “… the famous Sandwalk, where Darwin used to take his allotted exercise after each spell of work, freshening his mind and shaping his thought for the task in hand.” Darwin used stones to count laps, kicking one aside each time he passed, to avoid interrupting his thoughts as he walked his “thinking path.”:

Here I’m walking along the Sandwalk in the footsteps of Charles Darwin, birding as I go.  From Darwin’s notes: “Hedge-row in sand-walk planted by self across a field (years ago when I held field which had from time immemorial been ploughed & 3 or 4 years before the Hedge was planted, had been left as pasture — soil plants, chiefly Hard or clayed & very poor.— . . . plants, have now sprung up in hedge — preserves how the seeds having been brought by birds, for all are esculent & the protection afforded by spinose thorns — a sort of common land—” Photo: Renate Sutherland.

Part 2 to follow.

We have all likely had the experience that when we learn a task it becomes easier to learn a distinct but related task. Learning to cook one dish makes it easier to learn other dishes. Learning how to repair a radio helps you learn to repair other electronics. Even more abstractly – when you learn anything it can improve your ability to learn in general. This is partly because primate brains are very flexible – we can repurpose knowledge and skills to other areas. This is related to the fact that we are good at finding patterns and connections among disparate items. Language is also a good example of this – puns or witty linguistic humor is often based on making a connection between words in different contexts (I tried to tell a joke about chemistry, but there was no reaction).

Neuroscientists are always trying to understand what we call the “neuroanatomical correlates” of cognitive function – what part of the brain is responsible for specific tasks and abilities? There is no specific one-to-one correlation. I think the best current summary of how the brain is organized is that it is made of networks of modules. Modules are nodes in the brain that do specific processing, but they participate in multiple different networks or circuits, and may even have different functions in different networks. Networks can also be more or less widely distributed, with the higher cognitive functions tending to be more complex than specific simple tasks.

What, then, is happening in the brain when we exhibit this cognitive flexibility, repurposing elements of one learned task to help learn a new task? To address this question Princeton researchers looked at rhesus macaques. Specifically they wanted to know if primates engage in what is called “compositionality” – breaking down a task into specific components that can then be combined to perform the task. Those components can then be combined in new arrangements to compose a new task, like building with legos.

They taught the macaques different tasks, such as discriminating between shapes or colors. The tasks had a range of difficulty, for example they had to distinguish between red and blue, with some of the colors being vibrant and obvious while others were muted or ambiguous. To indicate which shape or color they were perceiving they had to look either to the upper left or the lower right on some tasks, or the upper right and lower left on others. Essentially they had to combine a sensory perception to a motor activity. The question was – when the tasks were shuffled, would they use the same brain components (or what the researchers call “subspaces”) in a new combination to perform the new task? And the answer is – yes, that is exactly what they did.

Obviously, this is a rather simple construct, and it is only one study, but the evidence is consistent with the compositionality hypothesis. More research will be needed to confirm these results for different tasks with more complexity, and of course to replicate these results in humans. I think the idea of compositionality makes sense, but not everything that makes sense in science turns out to be true. Some ideas in neuroscience are discarded when they turn out not to be true, like the notion of the “global workspace” (an area of the brain that was the common networking hub of all consciousness).

There is also already research indicating that compositionality is just one feature of learning that exists on a continuum (probably) with another feature of learning – interference. The way you measure interference is to train someone on task A, then train them on related task B, and then retest them on task A. If learning task B reduces their performance on task A, that is interference. You have probably experienced this as well – you sometimes have to “unlearn” a new task to go back to an older one. My family has two cars, one with regenerative braking and one without, with each requiring a slightly different driving style. With regenerative braking, when you lift off the gas it slows the car through resistance. Switching back and forth causes a bit of interference, and it takes a moment to adapt to the new task.

It turns out, humans and neural networks display similar patterns of compositionality and interference. People exist along a spectrum with “lumpers” transferring skills from one task to another more easily, but also displaying more interference, and “splitters” who do not transfer skills as much, but also do not suffer interference as much. It appears to be a tradeoff, with different people having different tradeoffs between these two features of learning. In other words, if you reuse cognitive legos to build new tasks, that will make it easier to learn new related tasks because you can repurpose existing skills. But then those legos are networked with other tasks, which can cause interference with previously learned tasks using the same legos. Or – you build an entirely new network for a new task, which takes more time but does not repurpose and therefore does not cause interference with previously learned tasks. Which is better? There is likely no simple answer, as it is probably very context dependent.

Further, if people fall along the lumper to splitter spectrum, is that consistent across cognitive domains? Can one person be a lumper for some kinds of tasks and a splitter for others? Can we start as a lumper, but then morph into a splitter if we switch among tasks frequently over time, thereby reducing interference? Will different learning mechanisms favor adopting a lumper vs splitter strategy? Sometimes I want to be flexible and adapt quickly, at other times I may want to invest the time to minimize interference as I switch among tasks. Is there a way to get the best of both worlds?

That’s the thing with interesting research, it usually provokes more questions than it answers. Lots to do.

 

The post Cognitive Legos first appeared on NeuroLogica Blog.

Searching for exomoons - moons the orbit around another planet - was one of the most exciting capabilities expected of the James Webb Space Telescope (JWST) when it launched in late 2021. So, after four years of operation, why hasn’t it found one yet? Turns out it’s really, really hard to find a moon around a planet light-years away. A new paper available in pre-print on arXiv from David Kipping of Columbia University (and Cool Worlds YouTube Channel fame) shows why. They used 60 hours of time on JWST’s NIRSpec instrument and weren't able to definitively confirm the existence of a possible exomoon.

Vets have developed a training protocol to help cats benefit from water-based rehabilitation therapies, in spite of their natural aversion to water

From a new collection of shorter fiction by Brandon Sanderson to Simon Stålenhag’s new work, via a Stranger Things novel, December’s new sci-fi features some compelling and intriguing offerings

Archaeologists have gathered evidence from hundreds of Bronze Age sites in western Turkey that could be remnants of a civilisation that has been largely overlooked

Now through the end of the year, all Skeptoid donations will be matched up to $27,500.

Learn about your ad choices: dovetail.prx.org/ad-choices

In the sadly continuing story of how Health and Human Services Secretary RFK Jr. is working to eliminate vaccines, we look at a useful idiot, Dr. Vinay Prasad, and how he is weaponizing dead children to justify making vaccines harder to approve.

The post Robert F. Kennedy, Jr. is definitely coming for your vaccines, part 5: VAERS and a useful idiot at the FDA first appeared on Science-Based Medicine.

What can water in Jupiter’s atmosphere teach scientists about the planet’s composition? This is what a recent study published in the Proceedings of the National Academy of Sciences hopes to address as a team of scientists investigated the distribution of water with Jupiter’s atmosphere. This study has the potential to help scientists better understand Jupiter’s atmospheric dynamics, composition, and evolutionary history.

What steps can be taken to improve and enhance the lifetime of space solar cells? This is what a recent study published in Joule hopes to address as an international team of researchers investigated new methods for improving both the lifetime and performance of space solar cells from the harshness of space weather and radiation. This study has the potential to help scientists and engineers develop new space technologies, especially as several private companies and government organizations are extending their reach into space.

Chemical rockets have taken us to the Moon and back, but traveling to the stars demands something more powerful. Space X’s Starship can lift extraordinary masses to orbit and send payloads throughout the Solar System using its chemical rockets but it cannot fly to nearby stars at thirty percent of light speed and land. For missions beyond our local region of space, we need something fundamentally more energetic than chemical combustion, and physics offers or in other words, antimatter.

Growing fresh lettuce and strawberries might sound mundane until you consider doing it on the Moon or Mars. An international team has created a roadmap for cultivating plants in space, addressing one of NASA's highest priority challenges for long duration missions. These aren't just about providing fresh food for astronauts, plants in space will recycle air and water, produce pharmaceuticals, process waste, and support mental health during years long journeys to distant worlds. With the first lunar greenhouse scheduled to operate during NASA's 2027 Artemis III mission, humanity is on the verge of becoming an agricultural species across multiple worlds.

A team of scientists have detected electric discharges on Mars for the first time, confirming a phenomenon that was theorised for decades but never directly observed until now. The Perseverance rover's microphone accidentally captured the electromagnetic and acoustic signatures of sparks generated inside Martian dust devils, similar to the static shocks you might experience touching a metal door handle. This discovery changes our understanding of Mars's atmospheric chemistry and could explain longstanding mysteries about the rapid disappearance of methane in the Martian atmosphere, while also raising important safety considerations for future human missions to the red planet.

Have scientists finally confirmed the existence of the first exomoon? This is what a recent study accepted for publication in Astronomy & Astrophysics hopes to address as a large international team of researchers investigated new methods for identifying an exomoon orbiting a gas giant exoplanet. This study has the potential to help scientists develop new methods for finding exomoons, the latter of which has yet to be confirmed.

It looks as if “Real Time” will be off the air for a two months: yahoo! news says, “. . . . Maher will be taking a break from Real Time until late January.” I’ll miss the humor and also the posts.  We don’t even have a “new rules” post today, but below are two minutes of Maher guessing what the headlines will be when he’s absent.

This one is pretty funny, albeit brief.

We’ve known for a long time that sexual selection—ultimately caused by differences in gamete size—can produce marked differences in the appearance and behavior of males versus females within a species. Often males are more ornamented than females, with bright colors and long feathers or ornaments on the head.  We also know that colors and ornamentation of males puts them at a disadvantage in certain respects, as they are more easily detected by predators than are the females, or have difficulty flying because of exaggerated feather displays. This disadvantage also applies to sexually-selected “weapons” like deer horns and moose antlers, which are shed and have to be regrown, at great metabolic expense, each year.

Perhaps the most famous of these features is the tail of the peacock, in which males have long, decorated, and spreadable tails that females lack.  We are pretty sure that this difference is due to sexual selection because experiments show that the “eyespots” on the male tails attract females: the more eyespots you have, the higher chance you have of reproducing. Thus the genes for exaggerated tails accumulate via sexual selection by females.

Of course female preference plays a key role here, as that preference has to exist to give more elaborate males a reproductive advantage.  We don’t fully understand, however, exactly why females prefer many exaggerated male traits. In some cases, like the orange-red color of the male house finch, we have an answer.  As I said, there are also costs of sexually-selected male traits like big bodies (elephant seals) or antlers (moose), who use them to directly fight for access to females. (Darwin called this the “law of combat”.)

But in most cases we don’t understand why females prefer certain bright colors or long tails, though we have theories that are largely untested. This difference in patterning and color was called “the law of beauty” by Darwin, who was the first person to suggest the idea of sexual selection (1871).

Both forms of sexual selection show that this type of selection—really a subset of natural selection—involves tradeoffs.  Males sacrifice flight ability, become more obvious to predators, and have to re-grow antlers and horns each year, which are considerable disadvantages. But those have to be more than compensated for by either the success in combat or the increased attractiveness to females of males with those traits—otherwise the exaggerated traits would not have evolved.

A new paper in Biology Letters (click title screenshot below) shows a novel form of tradeoff in pheasants, and the first such tradeoff known in any animal. In two species of pheasants, males have evolved “capes” around their neck that, when expanded, occlude the male’s visual field (but not the female’s), as well as head feathers that also appear to block the male’s vision.  These are sexually selected traits.  Noticing them, the five authors hypothesized the tradeoff: in the two species of pheasant with head and neck ornamentation (the Golden and Lady Amherst pheasant), they tested whether the male’s head feathers blocked part of his visual field compared to females in the same species.  As a control, they used two pheasant species (Silver pheasants and Green pheasants), in which males don’t have head ornamentation that would block the visual field.

The authors then measured the visual field of males and females of all four species, and, lo and behold, males of the Golden and Lady Amherst’s pheasants did have a considerable blockage of the vertical field of vision compared to conspecific females, while there was little or no difference between the sexes in the two control species.

Click the title below to read the original paper for free, or find the pdf here. There is also a brief précis piece in Science if you want the abridged version.  The quotes and figures below come from the original paper, while the six full-bodied photos of the pheasants come from Wikipedia (credits shown).

First, the birds.

A male Golden pheasant, Chrysolophus pictus:

Bjørn Christian Tørrissen, CC BY-SA 3.0, via Wikimedia Commons

. . . and a female Golden pheasant. The sexual dimorphism is bloody obvious.

Photo produced by David Castor (user:dcastor)

The heads of males (l) vs. females (r) of the Golden Pheasant, taken from the paper itself. You can see how the male’s head feathers could occlude its vision.

The one other “experimental” species with male vision-occluding feathers.

Male Lady Amherst’s pheasant, (Chrysolophus amherstiae):

Sylfred1977, CC BY-SA 3.0, via Wikimedia Commons

A female Lady Amherst’s pheasant:

Lencer, CC BY-SA 3.0, via Wikimedia Commons

And one of the two control species, the Green Pheasant, (Phasianus versicolor). First, a male, with vision not impeded by a crown. (The other control species, the Silver pheasant, Lophura nycthemera, isn’t shown.) Both of the control species show sexual dimorphism of color and plumage in the expected direction, but there are no feathers on the male’s head that could block his vision.

Alpsdake, CC BY-SA 3.0, via Wikimedia Commons

And a female:

Alpsdake, Alpsdake, CC BY-SA 3.0, via Wikimedia Commons, via Wikimedia Commons

How did they measure the visual field of males and females? They simply put the pheasants in a padded box and fixed their heads firmly so that they could not move. (No pheasants were harmed in this study, which is excellent.) Then, to measure whether an eye could see at a certain angle, they shined a light on the eye. If there was a reflection from the retina at the back of the eye, that meant the bird could see the light from that angle. By performing many tests at various angles around the head, the researchers were able to judge the field of vision of each bird. They could also do this in pheasants whose heads were tilted up or down (see below).

The differences were most pronounced in the vertical line of sight. For example, as shown below, when the head is horizontal or looking down,  the male of the Golden pheasant sees 30° less above his head than does the female.  This would be a problem because, as the authors say, “Sexually selected traits such as feather ornamentation of male birds can act as an impediment to movement and predator detection.”  When you’re a male pheasant busily foraging on the ground, which is how they eat, you may not see an approaching predator. That is the cost of the sexual selection that produced head and neck feathers. (The figure says this is a Lady Amherst’s pheasant but it is apparently a Golden pheasant.)

From the paper (Fig 1). Panels (C) and (D) show vertical cross-sections through the binocular fields in the mid-sagittal plane of the head. The head drawings represent typical resting postures for each species, based on photographs of birds observed in aviaries.Panels (I) and (J) display vertical sections of binocular fields when the birds focus on prey items on the ground during foraging

Here are all four species.  The Lady Amherst’s pheasant has an even more severe impediment of vision in the male: he can see vertically a full 40° less than do conspecific females.  In contrast, the sex difference in the control species is much less: a mere 5° reduction in males in the Silver pheasant and no difference in the green pheasant.

(From Fig. 2 of paper): Figure 2. Vertical sections through the binocular fields in the median sagittal plane of the head of four pheasant species. The line drawings of the heads of the birds show them in the approximate orientations typically adopted by the species when at rest, as determined from photographs of birds held in the hand in their aviaries. The left panel shows males and right panel females of (A,B) golden (Chrysolophus pictus), (C,D) Lady Amherst’s (C. amherstiae), (E,F) silver pheasants (Lophura nycthemera) and (G, H) green pheasants (Phasianus versicolor)

The figure below in the paper gives a three-dimensional depiction of a bird’s view, with males on the left and females on the right. You can see that the males are effectively blind (black area) over a much larger space than are the females, and that space is mostly above the bird’s head. Since pheasants are ground foragers, blacking-out of “down” vision would be a very serious impediment, making males unable to locate food. Blocking “up” vision would surely have a smaller cost.

(From paper, Fig. 1): Panels (K) and (L) provide perspective projections of retinal field boundaries from the bird’s own viewpoint, with blind sectors highlighted in black.

The upshot is that the authors’ hypothesis is supported: males but not females in the pheasants having feathers around their eyes appear to have occluded vision, mostly above their heads.  Now we don’t know whether this occluded vision translates into a loss of fitness at all, much less a loss that is outweighed by the gain in fitness caused by the head and neck ornamentation.  Trying to answer questions about fitness is nearly impossible, as you’d have to measure survival and offspring production of males who have bigger and smaller feathers within a species (would you have to give the birds a haircut?). But there is a period of moulting in which males lose their head and neck feathers, and at least researchers could measure the field of vision, and perhaps foraging efficiency, during that period.  Nevertheless, I do suspect that occluded vision reduces fitness, and that the head ornamentation more than compensates for it.

Besides these results, the paper does show how natural selection and adaptation involves tradeoffs.  There are usually no mutations that are “universally” adaptive in that they convey a benefit without any cost. As I said, natural selection will favor the increase in frequency of mutations that produce net reproductive benefits to the individual that outweigh the costs.

We now have about four sets of photos, so I’m even more complacent. But please send in yours if you got ’em. Thanks.

Today we have regular Mark Sturtevant with a collection of insects and one vertebrate. Mark’s IDs and captions are indented, and you can enlarge his photos by clicking on them.

Readers may remember the recent post where I showed pictures of the dual emergence of 13- and 17-year cicadas during a trip to Illinois. I naturally did not take pictures of only cicadas, and so here are many examples of other insects I found in the parks that I visited. The rest will be in a later post.

First up is a banquet scene of ants feeding on a dead beetle. According to iNaturalist, the ants are a good match for Bearded Carpenter Ants (Camponotus subbarbatus). The picture took many hours to prepare since the ants were constantly moving around and the depth of focus would not capture all that I wanted. So I had to manually assemble some parts of most of the ants from different pictures to recover different focal points. Like focus stacking, only without the automated software that does that for you. I also moved some ants around to improve on the composition. For example, the one on the far left wasn’t where it is now. It’s worth clicking to embiggen this picture because jeez, it was a lot of work!!:

Next up are two pictures showing a bucket list item for me. This little beetle is from the Brentidae weevil family, and I was excited to find it since I don’t recall seeing a beetle from this family before. Weevils are divided into multiple families, but Brentid weevils are considered to be a primitive example of the group, identified by their straight snouts and lack of elbowed antennae. This particular species is the Oak Timberworm (Arrenodes minutus). Do you see the little mites? They were probably phoretic hitch-hikers, using the weevil for dispersal:

The grasshopper shown next is called the Green-legged Spur-Throat Grasshopper, Melanoplus viridipes. This small forest grasshopper has vestigial wings, although I don’t know why. Flightlessness in grasshoppers is more typical in large species where flying is not practical. In any case, they were pretty common in the screaming forest (screaming because of the millions of cicadas above), and it was fun stalking them because they are quite wily, moving to the opposite sides of leaves as I approached. But I snuck up on this one from a distance and this is a heavily cropped picture:

A few Lepidopterans are next. This is the caterpillar of the Hackberry Emperor Butterfly (Asterocampa celtis). Emperor butterflies are exceedingly common along forest margins, but the caterpillars are seldom seen (at least to me). Perhaps they are a species that stays hidden during most of the day. I believe this one was parasitized since it was not looking nor behaving normally. Notice the elaborate head ornamentation:

The butterfly in the next picture is the Question Mark (with the great binomial Polygonia interrogationis). They are close relatives of the similar Comma butterflies. Commas have a single white squiggle (a , ) on their hind wings, but here you can see a squiggle and a dot – so it’s a ?.:

This small moth is aptly named the Pale Beauty (Campaea perlata). One can easily recognize moths from its large family, Geometridae. Geometrids rest with their wings held out flat, and they usually have angular wing margins. The larvae of Geometrids are the familiar inchworms, and they have a distinctive way of crawling that probably everybody has seen:

Next is an odd little insect known as a Hangingfly (Bittacus sp.). Hangingflies look like craneflies, but they have four wings rather than two, and they belong to a completely different insect order. They hang vertically like this, but usually with their hind legs dangling free in order to snag small flying insects out of the air:

What is going on in the next picture? This insect is a plant bug in the family Miridae, and this particular species is Hyaliodes vitripennis. Plant bugs are Hemipterans that feed on sap, but the puzzle here are the eggs. They are Hemipteran eggs by the looks of them, but they seem way too big for this insect to have laid. Still, it showed no interest in moving away from the clutch:

Next up is a Hemipteran that is NOT a sap feeder. This was one of about a dozen hatchling Wheel Bugs (Arilus cristatus) that were milling around on some plants, slowly dispersing after emerging from eggs. Wheel bugs are predators, and are our largest species of assassin bug. You can see something of their eventual size and why they are called Wheel Bugs in the linked picture:

Finally, here is a dozy tree frog, quietly waiting out the day deep in the woods. It should be either Dryophytes chrysoscelis, or D. versicolor, but it is fairly impossible to visually tell them apart and their ranges broadly overlap. If the former species, then it is diploid with conventional pairs of chromosomes. But if it is the latter species, then it will be a tetraploid with four of each chromosome:

Jerry can most definitely correct me here, but this is one way in which a new species can emerge quite rapidly because once a fertile tetraploid population is established, any hybridization between tetraploid individuals and their diploid ancestors will produce triploid offspring, and these are generally sterile.

JAC:  Yes, Mark is right. An increase in ploidy can cause instantaneous reproductive isolation, and is in fact fairly common in plants.  One issue is how a tetraploid species (which could arise from the union of a diploid sperm and egg, or chromosome doubling after fertilization) can actually establish a population.  That usually requires that the new tetraploid species can occupy a different habitat from the progenitor diploid species, for if it’s outcompeted by the progenitor, then there is no ecological isolation and the tetraploid could be “hybridized to death”.

What can an ancient supernova teach scientists about Earth and celestial objects? This is what a recently submitted study to Astronomy & Astrophysics hopes to address as a team of scientists investigated the interaction of the remnants of supernova that occurred 10-million years ago with Earth. This study has the potential to help scientists better understand how Earth is influenced by celestial objects and what this could mean for the future of life on Earth, along with potentially habitable worlds beyond Earth.

What can equatorial jet streams on gas giant planets teach scientists about gas giant planetary formation and evolution? This is what a recent study published in Science Advances hopes to address as a team of scientists investigated the mechanisms of jet streams on gas giants (Jupiter and Saturn) and ice giants (Uranus and Neptune). This study has the potential to help scientists better understand not only the formation and evolution of giant planets in our solar system, but exoplanets, too.

A crew of tiny worms will be heading on a mission to the International Space Station in 2026 that will help scientists understand how humans can travel through space safely, using a Leicester-built space pod.