Stories tagged Diversity of Organisms

Sep
11
2011

There I was, sitting on my back porch enjoying the last days of summer, when I heard a sound--"zzzzzZZZZzzzzz"--first once, then again, and finally a third time in short succession. I heard coming from the trees the songs of the cicadas.

The cicada is a large (1-2 inches long) insect with a rather scary looking appearance.

The name cicada comes from Latin meaning "tree cricket" and while they aren't directly related to crickets, they are just as harmless.

About two weeks ago, as I was carrying something out to my car, I noticed a cicada in the process of shedding its exoskeleton to become an adult. You see, a cicada spends years underground as a nymph, feeding on the roots of various plants. After a certain number of years pass by (13 for some, 17 for other species) they emerge from their earthen nursery and climb up the nearby plants to get out of the reach of predators. Afterward, they molt their larval exoskeleton and become an adult. I couldn't believe my luck to have a cicada molting before my very eyes.

When I first noticed it, I saw something pink hanging from my tree. The exoskeleton had already split down the back and the newly adult cicada was climbing out of its old shell, all pink with spring green wings instead of black or brown. Initially, the wings were small green bumps on its back, but as they dried, the wings extended to their normal size. I was disappointed that I couldn't stay and watch its color change while the exoskeleton hardened, because that would also have been cool to see.

Cicadas are a rather delicate and sensitive insect. If the environmental conditions aren't just right with regards to pollution, acidity and temperature, when they emerge the cicadas will be deformed and often sterile. With this in mind, remember that while they might appear to be scary-looking, cicadas are quite harmless and actually a natural sign that the area in which you live is healthy.

Image courtesy of Bruce Marlin
Image location http://en.wikipedia.org/wiki/File:Magicicada_species.jpg.

Aug
06
2011

Archaeopteryx (Thermopolis specimen): Has the iconic transitional fossil had its feathers ruffled by a recent discovery? Not really.
Archaeopteryx (Thermopolis specimen): Has the iconic transitional fossil had its feathers ruffled by a recent discovery? Not really.Courtesy Mark Ryan
China has been producing some remarkable and groundbreaking dinosaur fossils in recent years that have caused paleontologists to reconsider long-held views. A recently described feathered dinosaur is no different. Xiaotingia zhengi, discovered in the Jurassic shales of the Liaoning Province, has been in the news lately because it supposedly knocked the well-known, so-called proto-bird Archaeopteryx from its perch as the earliest bird.

The study by paleontologist Xu Xing and his colleagues from the Chinese Academy of Sciences in Beijing appears in Nature. Their research, it seems, has determined that Xiaotingia and Archaeopteryx share many features that make the two of them more bird-like dinosaurs than dinosaur-like birds. Do you see the difference there? I guess I do. Anyway, essentially what it means is that Archaeopteryx has been pushed back a little and is just a bit more distantly related to birds than previously thought. The classification places both Xiaotingia and Archaeopteryx in with avian-like carnivorous dinosaurs such as deinonychosaurs, dromaeosaurids, and troodontids. The recent spate of fossils coming out of China can’t help but alter some our old views of the middle to late Jurassic fauna. Many dinosaurs (including non-avian ones) living during that time were equipped with bird-like features: e. g. long arms, feathers, wishbones, etc. They were all over the place.

But all you diehards out there in the Archaeopteryx-is-a-bird camp need not despair just yet. Dr. Xu himself admits that some of the conclusions in the study are based on pretty weak evidence. Archaeopteryx continues to rank as an exceptional transitional fossil (along with Xiaotingia). Its place in the transition has just shifted slightly, that’s all. Further studies and new fossils will no-doubt shake up the branches of the avian family tree again.

References:
Story at Pharyngula
New York Times story

May
23
2011

Tibicen linnei: An annual cicada
Tibicen linnei: An annual cicadaCourtesy Bruce Marlin (via Wikipedia Creative Commons)
Summer is heading our way and soon the familiar buzzing of cicadas will fill the air. But for some, particularly in the southern and eastern United States, the buzz will become a loud symphony of sound. That's because, this year, the Great Southern Brood will (actually already has in some places) reappear and millions of the insects will soon be crawling out of the ground to overwhelm us with their vast numbers and cacaphonic chorus.

Relax. Last weekend's rapture was a bust (or was it?), and there’s nothing to worry about in the biblical sense. It’s merely the latest appearance of Magicicada neotredecim and M. tredecim, two closely related species of cicada that show up every 13 years in the United States to fill the treetops with their buzzing song.

The most common genus of cicadas in the US is Tibicen and unlike Magicicada, cicadas in the genus Tibicen appear annually, not periodically. After a 2-3 year stint as nymphs, Tibecen cicadas emerge into their adult stage. The full-grown insect measures about 1-2 inches in length with long translucent wings and distinctive green, brown, and black markings on the middle of its body. Generations overlap so they show up every year and can be heard in many areas, including Minnesota, during the hot and steamy Dog Days of summer buzzing to high heaven. It’s that shrill, grating noise that builds in the air and sounds like someone is cutting up cement blocks with a chainsaw. As deafening as it can be, I like the sound, in much the same way I like the smell of rotting leaves in the fall, it triggers memories.

But I’m not sure how I’d feel about Tibicen's cyclical cousins - those belonging to the Magicada genus - that show up all at once in mass periodical emergences and put on huge choruses of buzzing. There are seven species that do this in the US, three in 13-year cycles, and four in 17-year cycles. Periodical cicadas are categorized into broods numbered in Roman numerals from I to XXX. The thirteen-year cycles occupy XVIII–XXX; seventeen-year cycles number I–XVII. Only about 15 broods are still recognized. There are still only seven cyclical species but some species emerge happen at different times in different regions, hence the number of broods. This year it will be a 13-year cycle called Brood XIX , and it is the largest of the 13-year cycles in terms of geography.

The numbers involved in a periodical swarm are huge but, as Vanderbilt biologist Patrick Abbot explains, the vast numbers increase the possibility of available mates and serve as a way to overwhelm the cicadas many predators, which include birds, snakes, turtles, spiders and wasps, and even fungi. It’s interesting that the periodical emergences have evolved into separate prime number cycles. The reason is probably to reduce competition between broods.

“Say you have two populations, one which emerges every five years and one which emerges every 10 years. Then they would emerge simultaneously every 10 years," Abbot said. "Whereas the period between simultaneous emergences between populations with 13- and 17-year cycles is 221 years."

Occasionally, two cyclical broods have been known to emerge simultaneously but usually the overlap is minimal. For example two 13-year broods rising at the same time but in adjacent regions.

During a brood’s synchronized emergence the number of individuals can be daunting. Some emergences have been estimated to contain something like 1.5 million cicadas per acre of land. That amounts to 800 tons (!) of biomass busily buzzing within a square mile of forest. Think of that!

But despite the huge numbers involved in a cyclical emergence, cicadas are pretty harmless, and don’t voraciously eat up crops like locusts do, nor do they sting or bite. The most damage done is by females when they make “v”-shaped slits in the bark of a twig to lay their eggs (I suppose this could feel like a sting if she mistakes your arm for a tree branch). But, come on, even this is nothing compared to a plague of locusts wiping out the summer corn crop.

The word cicada is Latin and means “buzzer” Very apropos, don’t you think? The males of the species spend a lot of time trying to get the attention of female cicadas by vibrating a membrane on their exoskeleton called tymbals. Each time the muscles contract or relax the tymbals they produce a click. Portions of the exoskeleton such as the abdomen or thorax help amplify the sound. The rapid vibration causes a shrill and (possibly annoying) buzzing, and each of the world’s estimated 2500-3000 species has its own distinct sound. The females, by comparison, make a rather boring click with their wings to attract males (I suppose the male cicadas don’t think it boring). You can replicate the female clicking by snapping your fingers in rapid succession a couple times.

When periodical cicada eggs hatch the nymphs drop down and burrow deep into the ground where they spend most of their lives sustaining themselves for several years ingesting fluids from tree roots and developing through five juvenile stages. Scientists suspect soil temperature triggers the emergence. When it reaches 64 degrees F., the nymphs head for the surface. It seems the likely catalyst since emergences in warmer, southern regions take place sooner than those farther north. Whatever the case, when they do emerge, the nymphs crawl up and attach themselves to nearby vegetation where they eventually molt out of their skins. They don’t begin adult activities until after their exoskeletons harden. So for the first 4 to 8 days after molting, they pass through a stage called teneral (meaning soft and tender) before the exoskeleton is complete. The adult stage of a cicada lasts anywhere from a couple weeks to a few months. Very short in comparison to their other life stages.

People eat cicadas in several areas of the world. And the females are meatier and more desired. I suppose the insect is a good source of protein but – there’s no way I’m ever doing that - I’d never eat one. Maybe I shouldn’t say “never”. Some Native American tribes supposedly survived times of famine by eating cicadas.

If you live in or are visiting an area that is or will soon be overrun by an invasion of the Great Southern Brood, rather than cowering in a corner and wailing and gnashing your teeth, head outside, go for a walk, and take in a symphony of cicada songs. While you’re out there enjoying the summer day, you can get even more involved by trying some of these neat cicada experiments. It will take your mind off the fact that you’re surrounded by 800 tons of buzzing biomass.

SOURCES and LINKS

Cicada Central
Magicicada.org
Vanderbilt release
Cicada Mania page

May
18
2011

R/V Hespérides, docked at Aloha Tower in Honolulu, Hawai`i
R/V Hespérides, docked at Aloha Tower in Honolulu, Hawai`iCourtesy C-MORE
How would you like to be aboard a ship, circumnavigating the globe, collecting samples from the world’s ocean?

That’s exactly what Spanish oceanographers are doing on their Malaspina Expedition aboard the Research Vessel, R/V Hespérides. Scientists and crew left southern Spain in December, reached New Zealand in mid-April, and recently arrived in Hawai`i. The expedition's primary goals are to:

  • build upon the historic 1789-1794 Malaspina expedition to promote interest in marine sciences among the Spanish public, particularly the nation’s youth
  • collect oceanographic and atmospheric data -- chemical, physical and biological – that will help evaluate the impact of global change
  • explore the variety of marine life, including microbes, especially those living in the deep sea
  • CTD: As this oceanographic instrument is lowered over the side of a ship, each gray Niskin “bottle” can be electronically triggered to collect a seawater sample from a different ocean depth.
    CTD: As this oceanographic instrument is lowered over the side of a ship, each gray Niskin “bottle” can be electronically triggered to collect a seawater sample from a different ocean depth.Courtesy C-MORE
    In connection with the latter two goals, the Malaspina scientists met with their colleagues at the Center for Microbial Oceanography: Research and Education (C-MORE). The two groups of scientists are working together. "We can exchange data on the local effects, what's happening around the Hawaiian Islands, and they can tell us what's happening in the middle of the Pacific," said Dr. Dave Karl, University of Hawai`i oceanography professor and Director of C-MORE.

    The Malaspina-C-MORE partnership is the kind of cooperation that can help solve environmental problems which stretch beyond an individual nation’s borders. The R/V Hespérides has now left Honolulu on its way to Panama and Colombia. From there, the scientists expect to complete their ocean sampling through the Atlantic Ocean and return to Spain by July. Buen viaje!

May
02
2011

the ocean's 5 major gyres
the ocean's 5 major gyresCourtesy NOAA
We often talk about the ocean ecosystem. And, indeed, there is really just one, world-wide ocean, since all oceans are connected. An Indian Ocean earthquake sends tsunami waves to distant coasts. Whitecaps look as white anywhere in the world. The ocean swirls in similar patterns.

However, oceanographers do find differences from place to place. For example, let’s take a closer look at the chemistry of two swirls, or gyres as they’re more properly called. Scientists have found a micro difference between the North Atlantic Gyre and the North Pacific Gyre. The Atlantic generally has really low levels of phosphorus, measurably lower than the North Pacific Gyre.

the element phosphorus among its neighbors in the Periodic Table of the Elements
the element phosphorus among its neighbors in the Periodic Table of the ElementsCourtesy modified from Wikipedia
Phosphorus is a very important element in living things. For example, it’s a necessary ingredient in ATP (adenosine tri-phosphate), the energy molecule used by all forms of life. Phosphorus is picked up from seawater by bacteria. All other marine life depends upon these bacteria, either directly or indirectly, for P. Therefore, if you’re bacteria living in the impoverished North Atlantic Gyre, you’d better be really good at getting phosphorus.

And they are!

Oceanographers at the Center for Microbial Oceanography: Research and Education (C-MORE) at the University of Hawai`i have made an important discovery. C-MORE scientists Sallie Chisholm, based at the Massachusetts Institute of Technology and her former graduate student Maureen Coleman, now a scientist at the California Institute of Technology, have been studying two species of oceanic bacteria. Prochlorococcus is an autotrophic bacterium that photosynthesizes its own food; Pelagibacter, is a heterotrophic bacterium that consumes food molecules made by others.

Pacific HOT and Atlantic BATS Stations: Microbial samples were collected at each location.
Pacific HOT and Atlantic BATS Stations: Microbial samples were collected at each location.Courtesy C-MORE
Drs. Chisholm and Coleman took samples of these two kinds of bacteria from both the Atlantic and Pacific Ocean. The Atlantic samples were collected by the Bermuda Atlantic Time-Series (BATS) program. The Pacific samples were collected in the North Pacific Gyre (about 90 miles north of Honolulu) by the Hawai`i Ocean Time-Series (HOT) program. The scientists discovered surprising differences in the genetic code of the bacteria between the two locations:

  • First of all, the Atlantic populations of both bacterial species have more phosphorus-related genes compared to their Pacific cousins. (Picture Atlantic microbes in Superman outfits with a big "P" on their chests!)
  • Secondly, in the Atlantic, Prochlorococcus has different kinds of P-related genes compared to Pelagibacter. Perhaps this means the two microbial species have evolved over time to use different phosphorus sources, to avoid competing with one another for this limited resource.

Drs. Chisholm and Coleman have discovered important micro differences between bacteria of the same species in two oceanic gyres. Now we can better understand how these microbes are working to recycle an important nutrient beneath the whitecaps.

Reference: October 11, 2010 issue of the Proceedings of the National Academy of Sciences

Apr
13
2011

Earth, our place in space
Earth, our place in spaceCourtesy NASA
Life scientists study…well, life. They want to know everything about living things on planet Earth. One of the first things biologists want to know is who’s here. What kinds of plants and animals live in a forest? --or in a field? –or in the ocean?

If you’re an oceanographer who studies marine mammals, perhaps you’d go to sea on a ship with a good pair of binoculars and hunt for whales. As you focused your binoculars you’d be able to see different kinds of whale species. As you looked closer, for example at Humpback Whales, you'd see that each individual whale has a different black-white pattern on its tail. You might even take a biopsy, a small sample of whale flesh, and do a more detailed study of genetic differences among individual Humpbacks.

But what if you’re a microbial oceanographer? You sure can't use binocs to hunt for microbes! How can you study individual differences among tiny creatures that are only one-one-hundredth the width of a human hair? How do you hunt and capture single-celled bacteria, like Prochlorococcus, the most common bacterial species in the world’s ocean?

Invent something!

laser-based micro-fluidic system
laser-based micro-fluidic systemCourtesy C-MORE
Young scientists, Sebastien Rodrigue and Rex Malmstrom, at the Center for Microbial Oceanography: Research and Education (C-MORE) were doing research in Dr. Sallie Chisholm’s C-MORE lab at the Massachusetts Institute of Technology when they adapted a “laser-based micro-fluidic system” used commonly by medical researchers, for the study of marine bacteria. With this method they could put each individual tiny Prochlorococcus cell into its own little pool of seawater.

And then the excitement began.

Prochlorococcus
ProchlorococcusCourtesy Dr. Anne Thompson, MIT
Even in scanning microscope photographs, each Prochlorococcus looks like just another teeny, tiny balloon; we can't see any individual differences. However, Sebastien and Rex used fast and inexpensive genetic methods and discovered an extraordinary variety of individual differences among Prochlorococcus. Of course the variety among these microbes doesn't have to do with tail patterns, like whales. Prochlorococcus vary in their method of getting nutrients, like iron, out of seawater.

So what? Why do we care?

We care A LOT because microbes like Prochlorococcus are operating at the nitty gritty level of cycling not only iron, but also other elements in the ocean. Like carbon. That's right, as in carbon dioxide accumulating in our atmosphere -- and ocean -- causing climate change and associated problems. The more we understand about individual differences among oceanic microbes, the more we'll understand how they influence and respond to changes in Earth's climate.

Feb
25
2011

Archaeopteryx: Thermopolis specimen.
Archaeopteryx: Thermopolis specimen.Courtesy Mark Ryan
This year marks the 150th anniversary of the announced discovery of the first fossils of Archaeopteryx, a remarkable chimera of both bird and reptile traits. The first evidence identified was a single feather discovered at a limestone quarry in Solnhofen, Germany. This was in 1860. The German paleontologist Hermann von Meyer described the fossil in 1861, naming it Archaeopteryx lithographica. That same year, the first skeletal remains came to light, and although headless, the London specimen, as it became known, showed clearly both avian and reptilian characteristics.

The unique and iconic fossil appeared just two years after publication of Charles Darwin’s On the Origin of Species and helped bolster the naturalist’s theory of evolution through natural selection because its appeared to be a transitional fossil between reptile (dinosaur) and bird. Could Darwin have asked for any better evidence?

Since then nine other specimens have been found, including the Berlin specimen around 1877, which is considered one of most complete. For many years some Archaeopteryx specimens languished in collection drawers because they had been initially misidentified as another creature entirely. In 1970, Yale paleontologist John Ostrom was investigating a so-called pteradactyl fossil at a museum in the Netherlands, when he realized it had been misidentified and was actually an Archaeopteryx. The fossil had been found at Solhofen in 1855, five years prior to the feather! The museum curator was so shaken by Ostrom’s announcement, he clumsily wrapped the specimen in a paper bag and presented it to Ostrom so he could take it back to Yale for further study. Ostrom, by the way, re-ignited the “birds are dinosaurs” debate in the 1960s after his discovery of Deinonychus and his comparison of its structural features with those of birds.

The Thermopolis specimen, the latest Archaeopteryx fossil, became known around 2005 and was donated anonymously to the Wyoming Dinosaur Center in Thermopolis, Wyoming. I happened to visit the museum in June of 2007 during the first week the fossil went on public display, and was able to see the spectacular specimen firsthand. The small fossil (about 1.5 feet square) was displayed behind a small, glass opening in the wall. There was no crowd to speak of so I was able to take in and photograph the fossil for a long stretch of time by myself. Looking at it, your eye is immediately drawn to the distinct feather impressions evident on both its wings and tail. The head, arms, and legs are spread out across the slab, and even though it died 150 million years ago, it looks as flat and fresh as road kill on a modern highway.

About the size of a large crow, Archaeopteryx was an odd amalgam of both bird and reptile. It had slightly asymmetrical flight feathers, wings, and a furcula (wishbone) - all traits found in birds. But its pelvis, skull and sharp teeth were reptilian (although some skull features are bird-like), and it ha a long tail like a reptile. Its bones weren’t hollow, like the bones of modern birds are, nor is its sternum (breastbone) very pronounced; it’s flatter and without a large keel where, in birds, muscles flight are attached. And it also possesses gastralia (“belly ribs”), a feature found in reptiles and dinosaurs. The inner toe (the hallux) in the Thermopolis specimen doesn’t appear to be reversed so it couldn't grasp or perch and was probably more earth-bound than arboreal. Interestingly, its second toe was extensible – meaning it could be pulled back and elevated for tearing into flesh, just like the middle toes of such dinosaurs as Troodon and Velociraptor. Truth be told, if its feathers hadn’t been preserved, Archaeopteryx would have been classified a carnivorous bipedal dinosaur. In fact, one of the existing Archaeopteryx fossil was first identified as a Compsognathus until preparation revealed its feathers.

Solnhofen and much of Europe in the Late Jurassic: A cluster of islands off the coast of the North American continent.
Solnhofen and much of Europe in the Late Jurassic: A cluster of islands off the coast of the North American continent.Courtesy Ron Blakey, NAU Geology
So what kind of environment did Archaeopteryx live in, and why are its fossils so well preserved? Well, during the Late Jurassic, southern Germany and much of the rest of Europe were pretty much a group of large islands poking out of the Tethys Sea off the coast of North America. What is today the Solnhofen quarry was then part of an island lagoon protected by a barrier reef. Geological evidence in the strata suggests the lagoon dried up several times followed by periods of re-flooding with seawater. Mixed into a brackish soup of coral debris and mud, and in a warm climate conducive to rapid evaporation, the lagoon’s bottom water levels became anoxic, that is depleted of oxygen. Low oxygen meant less bacterial activity and subsequently slow decomposition of any organism that happened to die or get swept into the stagnant lagoon. Burial in the carbonate muck was swift, leaving fresh carcasses no time to be pulled apart by currents or scavengers.

Solnhofen limestone has been used for centuries as a building stone. Because the rock’s matrix is so fine and splits so evenly (sediment deposition likely occurred in very calm waters), the material was later quarried to produce stones for lithography, a printing technique first developed in 1796, and the source of Archaeoperyx’s species designation. Many early scientific illustrations, including some of the first images ofArchaeopteryx were preserved as lithographs created using Solnhofen limestone.

Archaeopteryx commorative coin: Germany will issue the 10 Euro coin in the summer of 2011
Archaeopteryx commorative coin: Germany will issue the 10 Euro coin in the summer of 2011Courtesy Federal Republic of Germany
Solnhofen’s fossil record shows that the lagoon’s biological population was diverse. Fish, turtles, lizards and insects, crocodiles, crustaceans, ammonites, squid and starfish, mollusks, pterosaurs, and even the soft remains of jellyfish are preserved in the fine-grained limestone. But the premiere creature is of course the Archaeopteryx, which remains the earliest bird (or most bird-like dinosaur, if you will) known to date. As research on existing specimens continues and new fossils appear it's exciting to imagine what advances will take place in the dinosaur-bird connection debate. Whatever happens, Archaeopteryx lithographica will remain one of the most significant and iconic fossils ever discovered. It's no wonder that later this year on August 11th, the Federal Republic of Germany will issue a 10 Euro silver coin to commemorate the 150th anniversary of the discovery of its most famous fossil.

SOURCES and LINKS

Witmer Lab Archaeopteryx blog
UCMP Archaeopteryx page
Solnhofen limestone of the Jurassic

Feb
09
2011

Polyommatus blue butterfly
Polyommatus blue butterflyCourtesy Rongem Boyo
One of my favorite 20th century writers is the Russian-born Vladimir Nabokov (1899-1977). Many people were (and many probably still are) shocked by the subject of his best-known novel, Lolita, which he wrote in English in the early 1950s. But Nabokov’s use of the language in that book - and others - is at times so exquisite and so finely-crafted, that it’s equally shocking to realize that English wasn’t his native tongue but rather his second language taught to him by his governess while he was growing up in St. Petersburg. He was also well versed in French, so language played an important role in his life, as his many novels, poems, and essays attest. But growing up to become one of the 20th century’s greatest writers was not something he planned, because at age seven he had discovered another passion: collecting butterflies.

Nabokov said in later interviews that had it not been for the 1917 Russian Revolution, he would have probably been a lepidopterist at some obscure museum in St. Petersburg. But fate brought him eventually to the United States where (before publication of Lolita made him independently wealthy) he made his living mainly by teaching literature at Wellesley College and Cornell University. He also volunteered at the American Museum of Natural History - where he learned to dissect butterflies - and at the Harvard Museum of Comparative Zoology.

During the summer months he liked to mix his passions as he explained in the afterword to later editions of Lolita:

Every summer my wife and I go butterfly hunting. The specimens are deposited at scientific institution, such as the Museum of Comparative Zoology at Harvard or the Cornell University collections. The locality labels pinned under these butterflies will be a boon to some twenty-first-century scholar with a taste for recondite biography. It was at such of our headquarters as Telluride, Colorado; Afton, Wyoming,; Portal, Arizona, and Ashland, Oregon that Lolita was energetically resumed or on cloudy days.

Around 1945 he came up with a new theory of migration for the Polyommatus blue butterflies. Without the use of genetics and by studying anatomical features (mostly genitalia), Nabokov speculated that Polyommatus blues found in South America evolved by migrating in five waves from Asia across the Bering Strait. At the time the prevailing migration theories involved land bridges across the Pacific, so no one gave Nabokov’s hypothesis much weight.

Professional lepidopterists weren’t that impressed with Nabokov. They admitted he was decent enough researcher and at describing specimens (his published descriptions numbered in the hundreds) but they didn’t think he offered much in the way new ideas.

But now it seems Nabokov has been vindicated. A new report in the journal Proceedings of the Royal Society of London has determined - through DNA analysis – that Polyommatus blues have indeed evolved through five separate migrations from Asia over the Bering Strait.

“It’s really quite a marvel,” said co-author Naomi Pierce of Harvard. Pierce was part of a team of lepidopterists from England and the United States that made several expeditions to Chile to study and collect specimens of Polyommatus blues, then returned to the lab for gene sequencing and computer analysis of the data. The results showed that the Polyommatus blues did indeed originate in Asia, and were more closely related to that 10 million year-old ancestor than they were to their South American neighbors. But they also revealed that the first wave arrived when the temperature along the Bering Strait was warmer. But that temperature was in decline, and subsequent migrations brought in hardier species of Polyommatus, better suited to colder temperatures that correlated with the temperature range existing around the Bering Strait at the time of each wave. The conclusions matched Nabokov’s hypothesis to a “t”.

“By God, he got every one right,” Dr. Pierce said. “I couldn’t get over it — I was blown away.”

Paleontologist Stephen J. Gould included an essay in one of his many books about Nabokov’s split loyalties between art and science (he termed it “intellectual promiscuity”) proposing if the writer had kept focused on just writing he might have created another Lolita. On the other hand, Gould mused, if Nabokov had only studied butterflies, he could have become a well-known (at least in some obscure circles) lepidopterist. If it sounds like the old adage “you can’t serve two masters”, Nabokov seems to have pulled it off equally well in both arenas. I think had it not been for his writing and the lifestyle it afforded him, he wouldn’t have had the luxury of pursuing lepidoptery as fervently and successfully as he did; and without his butterfly collecting, he never would have written his masterpiece. If you asked the seven year-old Vladimir what he wanted most to be remembered for, his answer wouldn’t have been “writing a great novel”. He had another aspiration in mind, which he fulfilled several years later during one of his summer breaks from teaching. While visiting the Grand Canyon with his wife, Nabokov discovered a new species of butterfly which he named Neonympha dorothea in honor of a family friend who was traveling with them. His satisfaction poured out a couple years later in a poem:

I found it and I named it, being versed
in taxonomic Latin; thus became
godfather to an insect and its first
describer – and I want no other fame.

- On Discovering a Butterfly (1943) by Vladimir Nabokov.

SOURCES
NYT story
Bioephemera article

Jan
21
2011

Here's a story from the New York Times about a dog named Chaser that knows the names for more than a thousand items and even, according to her trainer, can perform more sophisticated linguistic feats such as understanding verbs and knowing that words might name a type of thing rather than an individual object.

Now, a dog that really, truly understood what you said to it would be a lot of fun to have around. (Of course, I'd probably have to curb my tendency to give dogs affectionate nicknames like Meathead and Stinky.) But even if critters like Chaser are "simply reading cues unconsciously given" by their trainers, isn't that a pretty amazing feat by itself? It seems to me that the ability to read little signals from humans, even ones that the humans aren't aware they're giving, isn't "simple" at all.

I once read a book by an animal scientist How many words does your dog know?
How many words does your dog know?Courtesy ~~Yuna~~
that said that all animals are geniuses at the skills they use to survive. Maybe Chaser really is doing something similar to what human babies do as they learn to speak and understand language. But if she's not, I'd be willing to bet that whatever skill she's using is no less fascinating.

Jan
21
2011

Pterodactyls
PterodactylsCourtesy Mark Ryan
A recently discovered pterodactyl fossil is providing lots of new information about the flying reptiles. The 160 million year-old fossil slab contains the remains of an adult specimen known as Darwinopterus, and was brought to light by a farmer who discovered it in Jurassic-aged deposits in China. Pterodactyls - also known as pterosaurs – populated the skies of the Mesozoic Era and were contemporaries of their distant relatives, the dinosaurs. Remains of pterodactyls aren’t uncommon and have been found in many parts of the world. What makes this fossil so unusual and valuable is that it also contains an unhatched egg, evidence that strongly suggests the adult is a female. The research team, made up of scientists from Great Britain and China, nicknamed the specimen “Mrs. T”.

Extensive examination of the fossil revealed that the adult specimen has wide hips, but is without a crest on its head. This contrasts with other known specimens of pterodactyls that have both large crests and narrow hips.

"Mrs T shows two features that distinguish her from male individuals of Darwinopterus,” said David Unwin, a paleobiologist from the University of Leicester who was involved with the study. “She has relatively large hips, to accommodate the passage of eggs, but no head crest. Males, on the other hand, have relatively small hips and a well developed head crest. Presumably they used this crest to intimidate rivals, or to attract mates such as Mrs T.”

Bird eggs are relatively large and hard-shelled, but the Darwinopterus egg is small and appears to be soft-shelled, like that of a crocodile. Dinosaurs, crocodiles and pterosaurs split off from a common archosaur ancestor during the Permian age about 250 million years ago.

This all means paleontologists will be now able to separate male pterodactyls from female pterodactyls. Until this recent discovery many had been categorized as separate species. The study appears in the journal Science.

SOURCES
Science Daily story
NY Times story