Work from researchers at the University of Liverpool appears in Nature and is described at Science Daily. They found that evolved responses in the bacteria led to faster evolution in the viruses.
I'm not sure that I agree with the premise that the study provides "the first experimental evidence that shows that evolution is driven most powerfully by interactions between species, rather than adaptation to the environment." There's abudant evidence that this is often the case - David Reznick's guppy studies in Trinidad come to mind. I do think that this contributes to an ongoing paradigm shift that recognizes the importance of interspecific interactions as a driving force in evolution. It's foolish to overgeneralize, however. The relative significance of environmental versus biotic factors depends on the particular system being examined. You'll have a hard time convincing me that biotic factors are more influential than physical ones in acidic hydrothermal pools or on polar icecaps.
Thursday, February 25, 2010
A little something for the zoology guys
This week we're looking at the acoelomate and pseudocoelomate worms, and I get the standard number of "Ewww, gross" comments when we're talking about some of the parasitic ones. But, I know they love it. Here's a colonoscopy view of Ascaris lumbricoides, the human intestinal roundworm...
and, a tapeworm revealed by the same technique.
and, a tapeworm revealed by the same technique.
Tuesday, February 23, 2010
Another new dinosaur...
..a giant herbivore that will be known as Abydosaurus. These come from a sandstone quarry in Utah's Dinosaur National Monument. The best thing about this discovery is that it includes a number of well-preserved skulls. That's unusual in the sauropods because their skulls were quite fragile. Had to be, as they were perched on the top of an extremely long neck.Best part of this story is the quote from the BYU vertebrate paleontology student who describes the "funnest project" that he's been involved with.
A little nomenclature trivia. The full binomial for the new beast is Abydosaurus mcintoshi. Abydosaurus is a reference to a city on the Nile where the head and neck of the Egyptian god Osiris were buried - a head and neck of the type specimen were unearthed at a site on the Green River. The species epithet honors Jack McIntosh, an American paleontologist whose greatest claim to fame was demonstrating that the Brontosaurus of our youth was not a real animal, but a chimerical blend of fossils of other sauropods.
Kind of a killer week....
...but stuff continues to happen.
Gotta rise at 4:30 in the morning to pick up a van-load of doughnuts that my honor society students sold to help fund their travel to meetings. It's a glamorous life I lead.
Wanna buy some doughnuts?
A couple of interesting stories at ScientificAmerican.com. First, the biogeographic phenomenon of bipolar species. No, not the guy down the street who locks himself in the house with the lights out one day and chases neighborhood kids down the street with a broom the next. These bipolars are the almost 300 species of invertebrates that are found in the polar waters of the Arctic and Antarctic Oceans - and apparently nowhere else. The intrigue surrounding their surprising distribution pattern dates back to their 1840s discovery by James Ross on voyages attempting to reach the North and South Poles. Many biologists in the intervening 160 years, including Charles Darwin, have attempted to explain the phenomenon.
Today, the best guess calls into a play a hypothesized deep-ocean current that moves water slowly from pole to pole. However, there's still a lot of conjecture. Among the questions - just how similar are they? DNA analysis should allow us to determine whether animals in similar habitats, but separated by almost 10,000 miles, are really as much alike as they look.
Check out the slideshow here.
The same online issue includes a discussion about the potential impact on island biotas of oceans swelling as the result of warming climates. As my biogeographers are finding out this week, a fundamental prediction from island biogeography theory is that small islands = fewer species. Will rising sea levels over the next century, projected to be anywhere from a few centimeters to almost a meter, unleash a double whammy on already stressed island communities?
While on the subject of island biogeography.... I was doing some YouTube-surfing today and ran across some great E.O. Wilson stuff. It was Wilson, along with Robert MacArthur, who published The Equilibrium Theory of Island Biogeography in 1967 and turned biogeography, and the rest of ecology, on its head. The theory remains one of the most powerful explanatory tools we have - and Wilson remains one of biology's most powerful spokesmen. I've seen him speak a few times, and had the pleasure of meeting him at last year's meeting of the Association of Southeastern Biologists.
Here, Wilson discusses the "Eureka moment"...
I know a lot of you are educators, or will be. I think that we should all aspire to help some young scientist have their own Eureka moment.
Nova produced a great documentary on Wilson in 2008. You can watch it online here. I particularly recommend "Chapter 4", where Wilson describes the experiment that he performed with Dan Simberloff in the Florida Keys that still represents the most ambitious effort to experimentally validate the equilibrium hypothesis. Very good stuff.
Gotta rise at 4:30 in the morning to pick up a van-load of doughnuts that my honor society students sold to help fund their travel to meetings. It's a glamorous life I lead.
Wanna buy some doughnuts?
A couple of interesting stories at ScientificAmerican.com. First, the biogeographic phenomenon of bipolar species. No, not the guy down the street who locks himself in the house with the lights out one day and chases neighborhood kids down the street with a broom the next. These bipolars are the almost 300 species of invertebrates that are found in the polar waters of the Arctic and Antarctic Oceans - and apparently nowhere else. The intrigue surrounding their surprising distribution pattern dates back to their 1840s discovery by James Ross on voyages attempting to reach the North and South Poles. Many biologists in the intervening 160 years, including Charles Darwin, have attempted to explain the phenomenon.
Today, the best guess calls into a play a hypothesized deep-ocean current that moves water slowly from pole to pole. However, there's still a lot of conjecture. Among the questions - just how similar are they? DNA analysis should allow us to determine whether animals in similar habitats, but separated by almost 10,000 miles, are really as much alike as they look.
Check out the slideshow here.
The same online issue includes a discussion about the potential impact on island biotas of oceans swelling as the result of warming climates. As my biogeographers are finding out this week, a fundamental prediction from island biogeography theory is that small islands = fewer species. Will rising sea levels over the next century, projected to be anywhere from a few centimeters to almost a meter, unleash a double whammy on already stressed island communities?
While on the subject of island biogeography.... I was doing some YouTube-surfing today and ran across some great E.O. Wilson stuff. It was Wilson, along with Robert MacArthur, who published The Equilibrium Theory of Island Biogeography in 1967 and turned biogeography, and the rest of ecology, on its head. The theory remains one of the most powerful explanatory tools we have - and Wilson remains one of biology's most powerful spokesmen. I've seen him speak a few times, and had the pleasure of meeting him at last year's meeting of the Association of Southeastern Biologists.
Here, Wilson discusses the "Eureka moment"...
I know a lot of you are educators, or will be. I think that we should all aspire to help some young scientist have their own Eureka moment.
Nova produced a great documentary on Wilson in 2008. You can watch it online here. I particularly recommend "Chapter 4", where Wilson describes the experiment that he performed with Dan Simberloff in the Florida Keys that still represents the most ambitious effort to experimentally validate the equilibrium hypothesis. Very good stuff.
Sunday, February 21, 2010
Saturday Science
We'll be starting a new program next month, in which we'll invite local school kids to campus for some Saturday activities. We've done a lot of this sort of thing in the past, and I'm pleased to bring it back. I'll probably start out with something easy, like a creek trip, and we'll work our way up to a reptile workshop this summer. If any readers have some ideas for activities, I'd love to hear them.
Whales and whale wanna-bes
Mentioned the other day that I'm reading a new book on whales by Phillip Hoare. Also seeing several whale-related news items...
A pair of papers in the latest issue of Science report new findings that relate to giant filter-feeders. In today's world ocean, the largest and most charismatic species are the great whales. The huge filter-feeding mysticetes, along with their fishy homologues like the whale and basking sharks, play a major trophic role in nutrient distribution. Well, there's some history there.
One paper, a collaboration between researchers at George Mason University in Virginia and the University of Otago in New Zealand, takes a prehistorical look at the relationship between the diversity of cetaceans and that of marine diatoms. By looking at records of whale fossils and correlating it with what we know about the history of planktonic diatoms, they found a significan
t relationship - over the last 30 million years or so, the diversity of whales has corresponded closely to that of diatoms.
Perhaps not surprising, but still good to know that the changes in cetacean diversity, as reflected in the fossil record, are real and related to a factor that we can understand.
A second paper, first-authored by Oxford's Matt Friedman, examines a group of bony fish that occupied the mysticete niche during the Mesozoic. There have been some hints at the significance of large, filter-feeding pachycormid fish, but they had been known only from the
Jurassic. An example is Leedsichthys, pictured at right, which was discovered in England in 19th Century. Leedsichthys lived in the Middle Jurassic, some 170 million years ago, and reached lengths of 30 feet or more. lived in the The new paper reports on pachycormids from Asia, Europe, and North America that show the pachycormids persisted throughout the Mesozoic, up until the end of the Cretaceous. At the time of their demise, the cetaceans were almost ready to take the stage.
A pair of papers in the latest issue of Science report new findings that relate to giant filter-feeders. In today's world ocean, the largest and most charismatic species are the great whales. The huge filter-feeding mysticetes, along with their fishy homologues like the whale and basking sharks, play a major trophic role in nutrient distribution. Well, there's some history there.
One paper, a collaboration between researchers at George Mason University in Virginia and the University of Otago in New Zealand, takes a prehistorical look at the relationship between the diversity of cetaceans and that of marine diatoms. By looking at records of whale fossils and correlating it with what we know about the history of planktonic diatoms, they found a significan
t relationship - over the last 30 million years or so, the diversity of whales has corresponded closely to that of diatoms.Perhaps not surprising, but still good to know that the changes in cetacean diversity, as reflected in the fossil record, are real and related to a factor that we can understand.
A second paper, first-authored by Oxford's Matt Friedman, examines a group of bony fish that occupied the mysticete niche during the Mesozoic. There have been some hints at the significance of large, filter-feeding pachycormid fish, but they had been known only from the
Jurassic. An example is Leedsichthys, pictured at right, which was discovered in England in 19th Century. Leedsichthys lived in the Middle Jurassic, some 170 million years ago, and reached lengths of 30 feet or more. lived in the The new paper reports on pachycormids from Asia, Europe, and North America that show the pachycormids persisted throughout the Mesozoic, up until the end of the Cretaceous. At the time of their demise, the cetaceans were almost ready to take the stage.
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