Stories tagged Biological Populations Change Over Time

Mar
21
2009

World wheat supply threatened

Rust resistant wheat
Rust resistant wheatCourtesy USDA - Scott Bauer
About a year ago in a Buzz post titled "Wheat futures" I expressed concern about the world's vulnerability to a wheat fungus called Ug99.

When wheat rust hit the North American breadbasket, in 1954, it wiped out 40 per cent of the crop. Norman Borlaug solved that wheat rust problem and earned a Nobel Prize by developing wheat that resisted stem rust.

About 10 years ago we identified a new stem rust in Uganda (that's why it's called Ug99) that is a mutation with the ability to once again wipe out more than 90 percent of the world's wheat varieties. This new variety of wheat rust has already spread from eastern Africa into Iran. It can then travel via Afghanistan to Pakistan into India and then China. We are lucky that a drought in Iran has slowed the successful propagation of the fungus spores.

Progress against wheat rust reported

At a workshop this week sponsored by Borlaug Global Rust Initiative more than 200 crop scientists from around the world discussed their efforts to crossbreed wheat varieties resistant to the new, virulent type of rust fungus.

The researchers led by Singh, of the Mexico-based International Maize and Wheat Improvement Center, have engaged in "shuttle" crossbreeding of wheat varieties in the search for Ug99-resistant properties, developing varieties in test fields in Mexico and Syria, exposing them to Ug99 in Africa, returning them for refinement, then exposing them again in Africa.
The resistance comes not from one or two genes that convey immunity, but from an array of "multiple minor genes" that together achieve "near-immunity" Scientific American

Multiplication of seed takes about 5 years

Last summer about 3.5 tons of resistant seed was grown (a total of 12 resistant lines). This seed has been sent to seven countries including Turkey. Those lines will produce all together several hundred tons of seed in these countries.

What we really need, what we really pray for, is another three to four years where the environment is not conducive to a stem rust epidemic. Then we would have sufficient varieties out there to avoid disaster.

Sources
New Wheat Strain Could Cut Fungus Threat: New York Times

Global Wheat Crop Threatened by Fungus: A Q&A with Han Joachim Braun Scientific American

Scientists gain in struggle against wheat rust Associated Press

Mar
19
2009

Dinos of a feather: New fossil discoveries throw the origin of feathers into confusion.  Or possibly Confucian.
Dinos of a feather: New fossil discoveries throw the origin of feathers into confusion. Or possibly Confucian.Courtesy treehouse1977

Science has known for a while that birds evolved from dinosaurs. We’ve discussed this before on Science Buzz, particularly here and here.

Now a new fossil has emerged from China that is complicating the picture. Tianyulong confuciusi was a small, two-legged plant-eater that lived in northeastern China about 130 million years ago. Its recently-discovered fossil included clear signs of feathers. This is nothing unusual—lots of dino fossils, especially from this part of China, have feathers.

What is unusual is that Tianyulong is not related to any previously known feather-bearing dinosaur. Not even remotely. All previously know dino feathers come from theropods, the two-legged meat-eaters like T. rex. Tianyulong was a type of hadrosaur—sometimes known as a “duck-billed dinosaur.” And the last time hadrosaurs and theropods shared a common ancestor was 230 million years ago!

This discovery raises several intriguing possibilities:

1. Perhaps feathers evolved very early in dinosaur history, far earlier than we now suspect. If the very first dinosaurs had feathers, then all other dinosaurs could inherit them, even after the various branches of the dino family tree split up and went their separate ways. But if that’s true, then why have we not found feathers on more dino skeletons?

2. Perhaps feathers evolved twice—once in the theropods, and once in the hadrosaurs. That would be pretty unusual. Right now, there seems to be no information on whether these new feathers are very similar to previously-known feathers, or completely different.

3. One thing has always bugged me about the whole bird-dino link. All dinosaurs fall into two major groups: those with hips shaped like those found in modern lizards, and those with hips shaped like those found in modern birds. But all the previous bird-like features, including feathers, come from the lizard-hipped group. Seems odd to me that nature would evolve bird-like hips twice. Maybe—just maybe—birds evolved from the bird-hipped dinosaurs.

Now, there’s tons of other evidence besides just hips to link birds to theropods, so nobody is going to be re-writing the bird family tree any time soon. All we can do is keep our eyes peeled for more interesting discoveries.

Mar
19
2009

He's not lying: Image subtly modified from an illustration on wikimedia commons
He's not lying: Image subtly modified from an illustration on wikimedia commonsCourtesy Haplochromis
Add it to the list! Which list?

The list of things that will kill you!

And, please, don’t quibble. The nit-pickers, the brick-counters, and the penny-slicers among you Buzzketeers might point out that, since we can really only die one time, a person can’t be killed by more than one thing, and therefore making a list is silly.

To all y’all, I say, “Shut it!” A person can be technically dead for several minutes and still be brought back into this town we call Life. Or, maybe, several fatal things could happen to you at very nearly the same time, and if the final straw could even be distinguished, we might accurately say that each contributed to your final achievement of death. Example: “Was it the hypothermia, the severe electric shock, or the brain parasites that killed JGordon?” “Hmm. Well if it was the brain parasites, him digging a fork into the toaster while trapped in a meat locker couldn’t have helped.” See?

So let’s recap the list so far:

1) Brain parasites
2) Electrocution
3) Hypothermia
4) Throwing knives (accidental)
5) Throwing knives (intentional)
6) Embarrassment (via brain aneurysm)
7) Misunderstanding enema directions
8) Falling off a high tree
9) Roller coaster decapitation
10) Poisoned dates
11) Fame

And the newest item?

. . . . .

“Predator X,” a carnivorous aquatic monster with a nine-foot-long skull, and foot-long teeth! It could totally kill you dead! The only caveat is that you would have to travel back to the cretaceous period, which is still about 65 million years further than we’re currently able to time travel. But, still, once you got there, you would be bitten like crazy.

Predator X has been lurking around the lower end of this list for a while now. For the last several years, paleontologists have been excavating a huge deposit of marine fossils on the arctic island of Svalbard. (That story was covered here on Buzz, back in October of 2006.) In fact, I wrote about another monster pliosaur uncovered at the site last March (See “Something Awesome.”) But Predator X, which was discovered on the last day of that field season, is an even more monstrous pliosaur. It looks like it was around 50 feet long, and weighed in the neighborhood of 45 tons.

(Pliosaurs, just to review, are extinct aquatic reptiles, and are not to be confused with “plesiosaurs.” Plesiosaurs are those long-necked, Nessie jobbers. Pliosaurs are related to plesiosaurs, but they had short, thick necks, and huge, scary heads.)

Back when the pliosaur we call “Something Awesome” was discovered, a paleontologist made a fun superlative sort-of statement about the new creature: “It was big enough to pick up a small car in its jaws and bite it in half.” Because Predator X is slightly larger, I’m going to save that scientist some time, and go ahead and say, “It was big enough to pick up a medium-sized car in its jaws and bite it in half.”

Very impressive, Predator X. You would so be able to kill me.

Mar
09
2009

Evolution: We're all tall enough to ride
Evolution: We're all tall enough to rideCourtesy kevindooley
When and where in Africa did modern humans evolve?

Jim Fairman, the director of the Science Museum of Minnesota's Science Division invites you to find out at a lecture this Wednesday night.

The Science Division is pleased to co-sponsor a lecture by Dr. Curtis Marean on March 11, 2009 in the auditorium of the Science Museum at 7 p.m. Dr. Marean, is a paleoanthropologist and expert on human origins. In this lecture he will broach the questions "where in Africa did modern humans evolve?" and "when did they become behaviorally modern and why then and at that place?" This lecture is free and open to the public, but seating may be limited (currently we have about 150 reservations, maximum seating 275). Please call the ticket office at 651-221-9444 and mention this lecture on March 11th. This free, public lecture is part of Marean’s residency through the Rydell Professorship at Gustavus funded by the Drs. Robert E. and Susan T. Rydell.

Marean is currently a professor at the Institute of Human Origins as part of the School of Human Evolution & Social Change at Arizona State University in Tempe. He teaches courses on the Stone Age of Africa, prehistoric and historic hunger-gatherers, zooarchaeology, and paleoecology. During the last decade he has put more effort into on-site archaeological excavations. In 2007, Marean and colleagues announced that they had found the oldest known evidence for the use of coastal resources, dating back to about 164,000 years ago, in Cave 13B at Pinnacle Point, on the South African coastline near Mossel Bay within the Cape Floral Kingdom.

The Rydell Professorship at Gustavus is a scholar-in-residence program designed to bring Nobel laureates, Nobel Conference lecturers, and similarly distinguished scholars to the campus as catalysts for enhancing learning and teaching. It was established in 1995 by Drs. Robert E. and Susan T. Rydell of Minnetonka, Minn., to give students the opportunity to learn from and interact with leading scholars.

Feb
16
2009

Evolutionary trees like the one Charles Darwin scribbled to illustrate his epiphany are still used today to help biologists understand and communicate the diversity of life. Like Darwin and his contemporaries, today’s evolutionary biologists are part of an ongoing effort to figure out how Earth's many species are related. As new tools help biologists to analyze evolutionary relationships, the tree of life changes and grows ever more complex.

How will biologists today and in the future to organize all of this information? No one knows for sure - but a number of computer scientists and software designers are taking a crack at it! In collaboration with biologists designers are creating programs that will allow researchers to share and search through enormous amounts of taxonomical information. Some programs, like UC Davis's paloverde, take cues from familiar web tools like WIkipedia and Google Earth, allowing users to search the tree of life from various perspectives and distances.

Beyond making research more accessible to scientists and the public, software tools like this will help scientists around the world work together in new ways - developing new medicines to treat constantly evolving diseases, new products and processes that take into account changing ecosystems, and to understand biodiversity on a local and global scale.

The potential of these tools is as big as the imagination of the designers and engineers behind them - what kind of tool would you create to help organize the tree of life?

Jan
21
2009

He's not eating it: He just thinks there's a millipede inside.
He's not eating it: He just thinks there's a millipede inside.Courtesy abmiller99
There’s an expression that I like… it describes a certain kind of broad, smug, and possibly insincere smile, but one of the words in it is altogether naughty. I am, if nothing else, sensitive to the delicate sensibilities of Buzz’s readers, and I hold the image of the Science Museum of Minnesota in the highest regard. And even though I do not write as a representative of the museum*, it would be a true blow to my childlike heart to see profanity on one of its webpages. (Especially if I were the one to put that profanity there in the first place.)

And so we will tiptoe around this expression, carefully, carefully… like careful cats.

The expression rhymes with “Spit-sleating gin.” Or “kit-beating kin.” Or maybe “wit meeting sin.”

Oh, what’s a good, inoffensive way to put it? Hmm. It has to do with the sort of expression of happiness you might wear if you had just finished eating a pile of poop, especially if you think someone else wanted some of that poop but didn’t get any before you polished it off, or maybe if you didn’t want anyone to know you had eaten the poop in the first place, and so were perhaps overcompensating in trying to look like your normal, smiley self.

Was that good? I think that was perfect.

Anyway, this expression was originally invented to describe the way dung beetles look pretty much constantly. Dung beetles eat poop all the time—some of them eat only poop—and for some reason they have the idea stuck in their heads that it’s a tremendously valuable commodity (little do they know, eh?), so they always have this big ol’ “look what I got, son” smile on their faces. You have to use a magnifying glass to see it, but the smile is there.

While this expression has since fallen into broader use, it seems that its original application is … decaying, if you will. It seems that not all dung beetles eat dung! Ah! Dogs and cats, living together!

That’s right—in the depths of the Amazon jungle, there’s a recently discovered species of dung beetle that has traded its hilarious culinary habits for something a little more awesome: hunting, maiming, decapitating, and eating big, toxic millipedes.

Researchers baited traps in the jungle with a whole variety of dung beetle foods—dung beetles love dung, so that was there, obviously, but some species will also snack on other items, like rotting fruit, fungus, dead animals, and, occasionally, millipedes. The scientists caught 132 species of dung beetles in the traps, but only one exclusively ate the millipedes. No poop for these beetles, or even dead millipedes—they were hunters.

The researchers closely examined the peculiar beetles, and noticed a couple tiny, yet important differences from similar looking species: the hunting beetles had elongated hind legs (trading their dung-rolling function for something a little more suited to grappling with prey), and modified jaws and teeth, for chewing open millipede exoskeletons.

The scientists think that the no-dung dung beetles have undergone speciation. That is, they have evolved into a new species in adapting to the pressures of their environment. See, it seems that dung really is a little scarce on the floor of the Amazon jungle, and some dung beetles moved on to different food sources (millipedes), to the point where they only ate that new food, and became distinct (albeit in small ways) from their old kin. So, while there is one less creature that can truly wear a zit-heating pin, I guess that the Amazonian dung beetles that still eat dung have a little more to grin about these days. It kind of balances out, doesn’t it?

*No, really, I don’t write as a museum representative. Watch: I kind of enjoyed Waterworld. Does the museum think that? Nope. Nobody thinks that, and my writing it doesn’t change the fact.

Jan
18
2009

Bird flu rears its head again in China

Bird flu death in China
Bird flu death in ChinaCourtesy broterham
A two year old girl in northern China has tested positive for bird flu. Early this month, January 5, a 19-year-old Beijing woman died of bird flu after handling poultry. She had purchased ducks at a market in Hebei Province, which neighbors Beijing. Although she had close contact with 116 people, no one around her has fallen ill.

Pandemic possibilities worry officials

Human-to-human transmission of avian flu is rare, but officials worry the virus could mutate and become a deadly pandemic. H5N1 has led to 248 deaths worldwide since 2003, including 21 in China.

Source articles:
Click this link to read all CNN articles about bird flu

Jan
14
2009

Conolophus rosada: Research scientist Gabriele Gentile holding the elusive pink iguana.
Conolophus rosada: Research scientist Gabriele Gentile holding the elusive pink iguana.Courtesy Photograph settings by Gabriele Gentile, photo shot by an assistant
A pink lizard that eluded Charles Darwin when he visited the Galapagos Islands nearly 175 years ago has been recognized as a new species of land iguana. Conolophus rosada is found only in the region of Volcan Wolf volcano on the island of Isabela.

"That Darwin might have missed this form is not surprising, because he stayed in the Galápagos only five weeks, and he did not visit Volcan Wolf [volcano], which to our knowledge is the only place on the archipelago where the pink form occurs," said lead researcher Gabriele Gentile of the University Tor Vergata in Rome, Italy. "What is surprising is that several other scientists visited in the last century Volcan Wolf and missed this form."

Two genera of iguana populate the Galapagos – land iguanas (Conolophus) and marine iguanas (Amblyrhynchus). The two branches split off from a common ancestor about 8-10 million years ago while still on the mainland. The pink iguana, which branched off the Colonophus line, can reach a length of more than 3 feet, and weigh up to 15 pounds. Park rangers first stumbled upon it in 1986 but not until now has it been recognized as a new, separate species.

Darwin spent only five weeks exploring the Galapagos when the HMS Beagle stopped at the archipelago to gather food for the voyage back to England. He investigated the island of Isabela but not around the Volcan Wolf volcano, the only area where rosada has been found. Overall, the naturalist wasn’t too impressed by the land iguanas he encountered on the Galapagos, He described them as “ugly animals, of a yellowish orange beneath, and of a brownish-red color above: from their low facial angle they have a singularly stupid appearance."

Good looks aside, the pink iguana presents other problems for modern scientists. Recent genetic analysis shows the rosada species diverged from other lines of land iguana about 5.7 million years ago. The trouble with that is the island of Isabela is only about one million years old and the oldest extant island in the chain, Espanola, is only 3-4 million years old. That means the split must have taken place somewhere else. But rosada hasn’t been found anywhere else in the Galapagos. How can this be?

One possibility is the split took place on the mainland before iguanas arrived on the islands, possibly floating there on rafts of vegetation. That would have been a long, miserable trip over 600 miles of open water. More likely rosada developed on an earlier island in the chain that no longer exists above sea level. Plate tectonics provide an explanation for this. Ocean crusts spread out from mid-ocean ridges located along the edges of plates moving away from each other. The Galapagos are part of the Nazca plate which is moving east-southeast (at about 7 cm/year) toward the continent of South America. The island chain was created (and is still being created) as the plate moved over a hotspot where a mantle plume is pushing up into the lithosphere and crust. Magma from the plume forms undersea volcanoes that build and sometimes break the ocean’s surface as islands. The Hawaiian Islands were created the same way but on a plate moving in a north-northwest direction.

As it moves toward the South American coastline, the heavier Nazca plate sinks beneath the lighter continental plate in a process called subduction. This means the earliest formed islands in the chain also sink and there is evidence of underwater seamounts between the archipelago and South America. Some of these have been dated to as much as 11 million years old, which means the pink iguanas could have split off from the land iguana line when older, earlier islands were still above sea level.

"This event is one of the oldest events of diversification among species in the Galápagos overall," Gentile said. "The Darwin finches are thought to have differentiated later than the split between the pink and yellow iguana lineages."

Despite rosada's evolutionary ranking, fewer than 100 pink iguanas are known to exist today and the species could be in danger of extinction.

It is, however, fitting that news of the pink iguana comes now. 2009 has been proclaimed the Year of Darwin marking the 200th anniversary of his birth and the 150th anniversary of the publication of his most famous work On the Origin of Species by Means of Natural Selection.

LINKS
Story on LiveScience
Year of Darwin info
Discovery.com story
Geology of the Galapagos Islands

Dec
30
2008

The 15 meter shantungosaurus: but if it were the new 19.3 meter dino... you could probably lie down in it's mouth. Very big.
The 15 meter shantungosaurus: but if it were the new 19.3 meter dino... you could probably lie down in it's mouth. Very big.Courtesy Vasilis
I can’t say whether that confusion is on the part of the Chinese state media, AFP news, or my own brain.

Apparently a massive deposit of dinosaur bones (the world’s largest in terms of area) has been found in China. Excavations at the site have unearthed about 7,600 individual bones from the late Cretaceous. The remains include examples of armored anklyosaurs, our favorite tyrannosaurs, and some spectacular hadrosaurs.

The aforementioned confusion arises with the hadrosaurs, I think. According to the article about the find (and I say “the article” because every science news site is running more or less an identical piece), “included in the find was the world’s largest ‘platypus’—or ‘duck-billed dinosaur’ in Chinese—ever discovered measuring 9 meters high with a wingspan of over 16 meters.”

Say what? I… think… something awesome is hidden in there, but someone here is confused: at least me, and perhaps China and/or AFP.

It turns out that our friend the platypus did indeed live during the cretaceous, alongside the dinosaurs, but I don’t think that’s what they’re referring to. “Wingspan” further complicates things, as neither platypuses nor duck-billed dinosaurs (hadrosaurs) really have the body type associated with a wingspan (you probably wouldn’t give the limb length of a beaver or a cow in terms of “wingspan,” right?)

Also “‘duck-billed dinosaur’ in Chinese”? I’m pretty sure that all of those words are, in fact, English. Yes, yes they are.

I have the feeling that someone involved in this story was really struggling with a second language, and the other person wasn’t helping at all.

Anyway… nobody cares about that, am I right? You clicked on this post because it said “dinosaur,” and I ruined it, didn’t I? Well, I’m sorry, but that was bothering me. I mean, “platypus”? Whatever.

But, yeah, this is pretty cool. China is a freaking dinosaur factory, and I’m into it. And this 9 meter high hadrosaur sounds neat. From what I could find, this guy, the shantungosaurus, is more or less the largest hadrosaur so far, and it measures about 50 feet long and maybe 7 meters tall (sorry to switch from imperial to metric there, but that’s how I roll). The shantungosaurus was also found in Cretaceous strata in China, so it might be reasonable to assume that it was similarly proportioned to this new dinosaur, and if that’s the case, this thing would be… about 19.3 meters long? Does that sound right? That’s about 63 feet long! That’s… huge!

Long-necked sauropods, like diplodocus or apatosaurus, reached lengths like that all the time, but for a two-legged hadrosaur 63 feet is massive. The T. rex, for comparison, maxed out at about 45 feet in length (I know, I know, apples and oranges, but we’re looking for some reference, aren’t we?)

The information on the site seems pretty bare-bones at this point, but it’ll be interesting to see what else comes out of the find.