There’s very little I can add to this, so I’ll send you over to an entry in Carl Zimmer’s blog, about a bird with curious wings.
This is probably no more complicated than evolving adaptive coloration or planting things on your body, but it’s a fascinating concept nonetheless. Birds developed an audible signal for communication that seems to work pretty well for them, but this is a species that developed an alternate method of doing so. To my untrained mind, this would seem to be a longer method to evolve than vocal cord variations, and one must wonder why this species departed from the norm (I believe it can still sing.) I mean, there’s a benefit to talking and eating at the same time, one I’ve wished I had, but I doubt that’s the key here. I can also speculate about the high frequency doing something for cleaning the feathers, but that’s little more than blind guessing. Still cool, though.
Courtesy of The Girlfriend just recently came a much-needed reminder, that the things that motivate us shouldn’t be shallow or related to money. And it brought back a memory of something I’m particularly proud of. This isn’t bragging (I don’t think), but a success story that I try to remember when I’m not feeling too hot.
There’s a part in there where you can see the shape and the swimming motion of the fish, which is strikingly similar to the effect I saw when I watched the dolphins (who were a bit faster.) Not only that, but see the little shrimp? Yes, you’ve seen them before, or at least, you have if you’ve been poking around the photographic gallery of my site enough.
This video is worth watching several times to see all the details. Catch the water jets of the cuttlefish as it moves around, and of course, don’t miss the stingray. One thing that the video displays very well, but perhaps isn’t described adequately, is that it takes a certain level of disturbance to get the dinoflagellates to fire off. When I witnessed this in Florida, waves splashing against rocks first drew it to my attention, but none of the fish movement within the water produced anything. It was only when the action became desperate that it became visible – I occasionally watched startled fish swim away from me with a streak of color, but otherwise it was dark. Thrashing my hand around certainly showed it, though.
Also, recognize that much of the video is shot at high magnification (the shrimp is probably only 2.5 cm long or so). I never saw individual points of light, and dinoflagellates are not discernable, even in bright light, to the naked eye. What I saw was just a haze of color. Just unreal.
And funny, I never really thought about the bioluminescence as a survival trait, but it makes sense now. Whales will eat them as part of the huge collective term “plankton,” but mostly the predators of such little species are slightly larger species like the grass shrimp and the porcelain crab, which serve as meals for even larger species that would have no interest in the dinoflagellates. In this case, the defensive mechanism seems to be more of a benefit collectively than individually, for two reasons. One, it takes an actual disturbance to light up the dinoflagellates, by which time they may already be eaten. And two, I imagine no small number of them get ingested by accident when something scarfs a shrimp down. Overall, more might survive by the reduction of predators, but the ones that have actually sent the warning, as it were, do so from being at a much higher risk. It works, but less efficiently than many other defensive mechanisms.
There are times when I regret not going to college, and finding out more about some of the things that interest me on a regular basis. But then I think about it, and realize right now I can concentrate on certain topics without having to satisfy some requirement for things I couldn’t care less about. So I guess the glass is still half unbroken, or something like that.
Anyway, say hello to a Common Spider Crab (Libinia emarginata) that can be found in Florida waters, among many other places. [The blotch in the left foreground is a Slipper Snail on the aquarium glass]. They’re shy, and their pincers are tiny and good only for feeding, so they utilize defensive camouflage, but in a totally cool way. They have the ability and instinct to obtain pieces of seaweed and plant them across their upper carapace with the help of a strange texture on its surface, and in this way, they blend into their typical habitat of seaweed-covered rocks. My specimen here, caught by hand and photographed within a fish tank, also sports quite a few small anemones, those ghostly white fringes all over its back. Whether it actually planted them itself or they simply liked it as a host, I cannot say.
Unfortunately, there’s a lot I cannot say about this one, but I’m trying to locate the answers to my questions, and plan to update this post when I have them. You see, simple coloration camouflage I understand. Simple behavioral traits, like holding still, I understand. But this is something different. Here we have a species that not only has a specialized physical trait, Velcro-like hooks in spots on the chitin called setae (which may even provide a preferential surface for anemones), but a specific behavior too, one that doesn’t seem to serve a combined or translatable purpose. You see, in order to get the seaweed to stay put, the crab actually chews the ends into a fray that catches on its setae, then puts the seaweed in place. Some studies have shown that it knows what seaweeds are more repugnant to its predators and preferentially chooses them. It has also been shown that this is more prevalent with the younger, smaller crabs, and that both the surface and the behavior disappear as they get older and less threatened by predators.
Evolution can be a convoluted thing, and the processes that lead to the forms we see now aren’t always easy to determine. The process of choosing select seaweeds, preparing them with a compatible surface, and placing them on its body has the deceptive appearance of reasoning and foresight, something that is undoubtedly lacking – crab brains aren’t very complicated. This is an ingrained process that’s been selected for over a very long period, but just how do you select for it?
It’s easy with adaptive traits like color. The harder it is to see a species, the harder it is to find it and eat it, so the ones with color that more closely matches the surroundings get eaten less and reproduce more, passing on those color genes. Simple. But a behavior that also relies on a specialized physical trait is something else, one that’s hard to work backwards from (and that, so far, I have not found answered by research.) I could perhaps see that the setae might have snagged seaweed by itself while the crab moved through a mass of it, and thus the crabs that grew rougher spots on their carapaces gained a camouflage benefit from the incidental adherence of stray vegetation. So, how did it evolve a behavior to place chewed stems on its back? I could spend a lot of time speculating, and have, but it hasn’t led anywhere convincing, nor do I think my guessing is meaningful in any way. We know, through roughly 150 years and uncountable hours of research, that these kinds of things develop in small increments over long periods of time. I just find it fascinating the traits that have been produced by the process, with only a few basic rules to produce them.
Since I’m sure you’ve read everything on this blog by now (snerk!), you already know I’m in favor of critical thinking. But, you may ask yourself (you have my permission), what does this look like? How is it applied? Directly to the forehead? Under a full moon? Far be it from me to let unasked questions go unanswered, so let’s do an exercise with a recent article from Wired Magazine. This is long, so I’ll get into my stride (read: frothy rant) after the jump.
Welcome to the first of a new topic, one I’ve been meaning to get to for a while. So far, I have two others in the queue which will show up before too long, so keep watching. This is my way of illustrating one of the reasons I got into nature photography in the first place.
The other day The Girlfriend and I checked out the local botanical garden while they were having a sculpture show. I can get vaguely interested in exotic plants, but usually spend my time chasing insects and lizards, and this was no exception. After a couple of hours, I’d packed away the camera equipment and we were heading out when I glanced down and noticed a little bit of chaff on my shirt. But it looked familiar, and as I watched, it confirmed my suspicions by creeping along my sleeve. I plucked it off and handed it to The Girlfriend, then dug the equipment back out.
As odd as this might look, most of what you see isn’t really part of the insect at all. This is the larva of a green lacewing fly. At this stage they’re predatory, meaning they eat other insects, mostly aphids. The cluster of junk on its back is molted exoskeletons of other insects – what kind, I haven’t been able to identify. Perhaps aphids, perhaps other lacewing larvae, spiders, or even preying mantis. It serves as camouflage, making a tasty insect (I’m assuming, anyway – something must find it palatable) into a dry bit of chaff. And, it serves an additional purpose, in that anything that does recognize it as food stands a much better chance of getting a mouthful of detachable skin (no Goldmember jokes now) instead of the juicy, nutritious insect.
My attempts at getting a good shot of it on The Girlfriend’s hand were cut short when it began biting her, so I popped it into the extension tubes – the only enclosed thing I had, since I was shooting with the digital and had no film cans handy. Don’t try telling me you’ve never done this. Back home, I used a branch as a set and started taking dozens of shots to try and capture the detail. Not only was the little thing so small that focus was difficult, and not only did it remain hidden under its trashheap, but it decided holding still was not the way it rolled. When your range of effective focus is measured in not more than three millimeters, this makes for a fun evening.
Yet, I still managed to get some interesting detail, like the long lashes on either side. These are appendages of the body that are there to support the debris. Once it pupates into the flying adult these vanish, and to the best of my knowledge they serve no purpose other than to support external camouflage while in this stage. Stripes and patterns to try and blend in? How plebeian! These guys grow a scaffold and construct a hunting blind on it, using only the very best of recycled materials. Considering the minuscule size of the insect’s brain, I have to imagine that a large portion of it is taken up with this instinct to build the structure it carries around. And apparently it works – just not against inquisitive photographers.
In case you wanted a better idea of the scale, here it is again, held by the chaff between my thumb and forefinger. And yes, just so you feel better about me sacrificing The Girlfriend in the name of bug pictures, it got its own chance to gnaw on me too. Lucky for it I hadn’t found it earlier when I was looking for some insects to feed a shy lizard.
Being back in central NY brought to mind something from many years back, one of those memories that I can’t define why I find it so compelling, I just do.
When I was in my late teens and early twenties (that’s in years – I still haven’t gone fully metric), I used to go out for walks late at night. I was in a rural area, where nighttime traffic was very sparse and streetlights almost nonexistent. It was very quiet, quiet enough to hear animals moving in the brush alongside the road, like the time I encountered a skunk that way. They’re very easygoing animals, because nothing messes with them, and he was well aware that I was following him, but as long as I kept myself four meters away, he was cool. I watched him scavenge dead frogs from the road where they’d been squashed by cars before he eventually wandered off the road again.
I got serious about photography after I left the state, and it took no small amount of time to find an image of the lake in my archive negatives ;-)
I lived about a mile from the northern tip of Cayuga Lake, one of the Finger Lakes of New York. Occasionally, when all was quiet, I’d hear a distant boom – just one, all by itself, and seemingly miles away. My imagination played with the ideas of a distant battleground or explosion, since that is what it sounded most like, but my senses told me (initially) that it was probably rail cars being coupled down at the rail line alongside the lake. Later on, as I thought about it, I realized this was unlikely – there was no rail yard nearby, just a line, and it always occurred singly and late at night when switching activity would have been scarce in so rural an area. Curious, but not particularly mysterious.
Until I read an article, many years later, about something called, “brontides.” These are seismic noises that no one has yet determined the origin of, that occur in several different distinct geographic regions. Lewis and Clark apparently heard them in the Rocky Mountains, saying they sounded like distant artillery (though if you’ve ever seen the original, unedited transcripts of their journals, it was probably more like “disttent artyllrees” – spelling was optional back then). But that article also mentioned the “lake guns of central New York,” and abruptly, I knew what I’d been hearing.
Or, that is to say, I didn’t know, any more than anyone else, but I knew now that it was a phenomena that dated back to the Native Americans at least, who provided the earliest accounts. There’s been a lot of speculation over the years – echoed thunder, mild earthquakes, igniting swamp gas, and natural gas deposits, to name a few. I feel comfortable putting the kibosh on most of those. I frequently witnessed heat lighting in the summer, which is simply reflected lightning from distant storms (probably cloud-to-cloud activity), and never once heard a hint of thunder from such shows. It seems silly to think that a single thump of thunder (not even a rumble) could be heard when no storm was present and no flash visible at all. Earthquakes have been reduced in likelihood since no recorded auditory event has ever coincided with seismic measurements, which tend to catch things people have never even heard or felt. And while the northern tip of the lake is known for swampy areas, I was close enough to see a lightshow should any gas have ignited, plus the fact that the sounds always seemed to come from further down the lake, towards open water. Not to mention that the spontaneous ignition of gas is extremely rare, but still shouldn’t be confined to such select areas (especially the Rocky Mountains).
To me, the last option I mentioned seems most likely – subterranean natural gas. No one knows how it could produce such noises, but the area is well-known for deposits, and they’d actually begun tapping them not long before I left. It still remains to be explained how natural gas deposits produce the sound, and why only in a few select areas, but so far, it’s the explanation with the best supporting evidence, at least for the “Seneca Guns” as they’re also called (the effect has been noticed for Seneca Lake as well, the neighbor of Cayuga.)
I just find it interesting that something I’ve heard and wondered about is part of an ongoing mystery. There’s also the realization that, in far too many cases, people assign mysterious, exotic explanations to what are usually mundane events. In this one, the phenomenon is right now more mysterious than I (and many others) had given it credit for.
I’m not much for blogging about details of my life, and try to concentrate instead on items of interest. This one falls somewhere in the middle, I think.
Last weekend, I flew up to central New York – a vast region often called “upstate” to differentiate it from New York City, which is what most people think of when they hear “New York.” If you’re one of those people, go look at a map, and get over it. I grew up in the Finger Lakes region, and returned there briefly for a kind-of family reunion. That was all well and good, I suppose, and I got to meet a cousin I hadn’t seen or talked to in, seriously, 37 years. But I was more motivated to get out and appreciate the area in late summer, because it’s a gorgeous area with some pleasant geography. Not being a winter person, however, I’m glad not to be there when the snows arrive…
With the help of my brother, I got down to see Carpenter’s Falls on Skaneateles Lake, a place I’d never been to despite the length of time I’d lived not far away. Access is fairly easy, though the trails close to the falls require sure-footedness. The flow doesn’t compare to many other waterfalls, but the drop is significant and the view is very nice and largely unspoiled.
As you might be able to see from the photo, the geology is primarily shale in this region, and provides another opportunity to the explorer: fossil hunting. My brother has become quite good at it, and is able to spot likely fossil-bearing rock from a short distance. So after we got done playing around the falls, we checked out an area close by that featured a shale face with easy access, and started searching. You might imagine that fossil-hunting involves meticulous work and those pointy hammers, but that’s only true in some cases, and not in this one. Certain shale layers host truly vast numbers of specimens, and the rock layers can be split apart with finger pressure. You can fill your pockets or a bag with specimens within an hour, easily.
This region of NY appears to feature fossils from the Devonian/Silurian period border, somewhere around 416 million years ago. Ocean life was abundant, but just starting to get complex, and terrestrial plants weren’t really around yet. Here I have a brachiopod, probably a spiriferidine, which shows the impression of the underside of the shell (towards the bottom of the photo), as well as the petrified remains of the shell itself (the lighter portion in the center of the pattern). The lines sloping crosswise to the “ribs” are growth lines of the organism. Don’t get the impression I know all of this offhand – I found out most of this while researching this post…
And I have this thin slab, 4 cm across at its widest point, that shows a collection of shells virtually indistinguishable from a modern day scallop – the only thing missing are the little tabs near the joint. Now, think about this a second: in 416 million years, the outward appearance (and primary function) of this organism has changed barely at all. In that same time, the first animals left the sea for the land, developed into countless species (like the dinosaurs), most of which vanished through extinctions, and we ourselves were probably some rodent or lemur-like thing when the dinosaurs died out 65 million years ago. Australopithecus afarensis, commonly referred to as “Lucy” and potentially our ancestor, comes from about 3.5 million years ago and looked only vaguely like us. But “scallops” barely changed at all. That’s what I call a successful organism. Not to mention tasty wrapped in bacon.
My favorite, from the short exploration, is this one. Splitting it open, I found two fossils overlapping. One of them certainly seems to be a plant, and from this time period, it would have to be aquatic, since land plants weren’t this fully formed. And since they rarely fossilize, I was pleased to see it. It’s draped across something that I haven’t yet identified, but I’m reminded irresistibly of chitin, the hard exoskeleton of something. It’s very thin, and actually has a hollow tunnel directly underneath it from yet another species – it appears it may have even conformed to the shape of the underlying organism. It’s also a distinctly different color from the surrounding rock. And I have both impressions, top and bottom, on the split rock layers. The whole chitiny structure is about the size of a fingernail, so the “leaves” are tiny and delicate indeed.
So, no trilobites yet, though they did exist in this time period, and I’ve found fragments, but this one is a neat find anyway. Where I live now in North Carolina, there are no fossils to be found – the whole area east of the Appalachian is erosion from the formerly great mountain range, which was formed during the collision with North Africa. Hundreds to thousands of feet below me was once a sea bed, but between me and that is silicates and mica, and any fossils that might have been in that have long since been destroyed by geologic heat and pressure. Essentially, the mountains erode into sand and have extended the shoreline from the base of the mountains down to where it is now. What I can find here is mostly pre-sand silicate rock. And clay. Lots and lots of clay. One of these days I’ll get out west and try to find something much younger but more interesting, like dinosaur tracks.
And now, another pause for thought. Long ago, some sea creatures died, and settled to the bottom. Something happened to cover them in mud – maybe a flood or a landslide, maybe just a storm. But there they remained, undisturbed, as layer after layer piled on top over thousands of years. The weight compressed the sediment, and it changed. And the minerals within it swapped places with the remains of the creatures, without actually disturbing things. Molecule by molecule, the creatures became statues of themselves.
The sea bed moved, thousands of miles at something much slower than a snail’s pace, and eventually lifted free of the waters. High above, hundreds of distant relatives of the dead creatures walked over the surface, never having the faintest idea what lay beneath, not even capable of thoughts of such caliber. Very, very recently, a glacier roamed over the land, ponderously slow yet many times faster than the movement of the rock itself that held the dead creatures, and with the force of gravity and tons of compacted snow and accompanying debris, gouged a huge tear in the landscape, down even past the layer where the sea bed used to be, down past much older sea beds. The glacier melted, and rains came, and the tear in the rock became a long thin lake. More rains, and yearly freezes, broke away flakes of the former mud flow, now rock, and tumbled them further down the ravine. Thousands upon thousands of similar creature remains became rubble, fragments, sand and grit, forever indistinguishable from the rock that used to hold them. But many remained, still in the layers of stone, but rapidly coming closer and closer to exposure.
A path nearby became a road, and rather suddenly, a couple of primate descendants of those dead creatures gathered the last few millimeters of stone encasing those remains, and abruptly exposed them to the light for the first time in 416 million years. A fragment of a story, so close to being lost forever like so many others, is revealed and pondered over. Soon, it will vanish again, but for a brief moment in time, a few dead creatures provide a tiny insight into life so very far in the past.
Maybe this is just the human perspective talking, but damn that’s cool!