Niedźwiedzki, G., Szrek, P., Narkiewicz, K., Narkiewicz, M., & Ahlberg, P. (2010).
Tetrapod trackways from the early Middle Devonian period of Poland.
Nature 463 (7277), 43-48
Saturday, January 9, 2010
Earliest tetrapod trackway
PZ Myers over at Phyrangula has a good summary of a recent paper about the discovery of what appears to be the oldest tetrapod trackway on Earth pushing the origin of amphibians from lobe-finned fish back some 20 million years to around 395 Ma - the early part of the Middle Devonian Period. The transition of vertebrates from sea to land has become a bit more complicated than we thought.
Friday, January 8, 2010
The sad state of science journalism at Fox News
Fox News has a January 7 Science & Technology news story titled "Cataclysm that killed dinos still taking lives today." I can not believe this was published by a major news organization. Some excerpts from the news story...
"The tremendous volcanic eruption thought to be responsible for Earth's largest mass extinction — which killed more than 70 percent of plants and dinosaurs walking the planet 250 million years ago — is still taking lives today."
There was indeed a mass extinction 250 million years ago (Ma). It was called the Permian extinction since it marks the end of the Permian Period of the Paleozoic Era of geologic time and the start of the Triassic Period of the Mesozoic Era. This is a fundamental division in the geologic time scale (placed there because the fossils show this huge extinction event and a big change in the type of life present on Earth).
Problem is, there were no dinosaurs around at this time - none. A lot of people think that there was only one mass extinction in the past and it was the one which killed off the dinosaurs (this was the K-T extinction which occurred between the Cretaceous Period of the Mesozoic Era and the Tertiary Period of the Cenozoic Era - another fundamental break in the geologic time scale that occurred about 65 Ma). In reality, there have been numerous mass extinctions with the Permian one being the worst.
Bottom line... Prior to 250 Ma, there were only reptiles (no dinos). Permian mass extinction 250 Ma. Dinos evolve and rule earth for some 180 Ma. K-T extinction 65 Ma. No more dinos. Big difference.
By the way, the Permian extinction was even worse than the quote above makes it sound. The 70% estimate is only for terrestrial vertebrate species (not nonexistant dinosaurs). One group of terrestrial vertebrates greatly effected by this event were the therapsids - also known as mammal-like reptiles (reptiles which eventually evolved into the mammals). Well over 90% of marine species became extinct as well (think about that for a minute).
Now I can understand non-scientists (and my students) not knowing about the Permian extinction. But a journalist and an editor at a major national news organization writing for the Science & Technology section? I'm not one of those knee-jerk "Fox News sucks" people - hell, I think CNN and MSNBC suck too - but in this case, they do indeed look like morons.
Reminds me of our local newspaper. Once, when we offered a night telescope observation on my Campus open to the public and once when they reported on an event on Campus called Science Olympiad, they confused astronomy with astrology. When confronted with this, the editor basically said "Don't make such a big deal out of this, it was just a typo." No, sorry. Typing "astronony" is a typo. Typing "astrology" is ignorance. To a science person, saying "XX Community College is offering a night astrology observation on Friday" is a glaring error that just jumps off the page. Of course, the paper (like most in this country) carries a daily astrology column but barely ever covers astronomy (or any other science except health-related ones).
Next excerpt...
"Scientists investigating the high incidence of lung cancer in China's Xuan Wei County in Yunnan Province conclude that the problem lies with the coal residents use to heat their homes. That coal was formed by the same 250-million-year-old giant volcanic eruption — termed a supervolcano — that was responsible for the extinction of the dinosaurs. The high silica content of that coal is interacting with volatile organic matter in the soil to cause the unusually high rates of lung cancer."
Coal is not "formed" by volcanic eruptions. Coal is basically buried and compressed plant material. And don't get me started on the term "supervolcano" - it's an invention of science journalists and media-whoring geologists who want to be on TV.
The real story here is actually quite interesting. About 251-250 Ma, huge volumes of basaltic lava erupted in the area that's now Siberia and resulted in an area called the Siberian Traps (traps is derived from a word meaning "steps" because sheet-like lava flows often erode into step-like plateaus). These basalt sheets cover a few million square kilometers - a vast area of the landscape. During the extrusion of this lava, there were also associated pyroclastic eruptions of ash that reached the stratosphere and were spread around the world.
Some of this ash, composed of very fine particles of the mineral quartz (silica), settled into swamps and peat bogs in what's now China. This silica was buried with the plant material and it all formed into coal that's mined today. Chinese laborors burn this coal for fuel in their homes and it releases the silica back into the atmosphere where it's breathed in and seems to cause increased rates of lung cancer.
A neat story. One that Fox News totally screwed up. Wired magazine has a much better story - Chinese coal formed during earth's greatest extinction is deadly.
"The tremendous volcanic eruption thought to be responsible for Earth's largest mass extinction — which killed more than 70 percent of plants and dinosaurs walking the planet 250 million years ago — is still taking lives today."
There was indeed a mass extinction 250 million years ago (Ma). It was called the Permian extinction since it marks the end of the Permian Period of the Paleozoic Era of geologic time and the start of the Triassic Period of the Mesozoic Era. This is a fundamental division in the geologic time scale (placed there because the fossils show this huge extinction event and a big change in the type of life present on Earth).
Problem is, there were no dinosaurs around at this time - none. A lot of people think that there was only one mass extinction in the past and it was the one which killed off the dinosaurs (this was the K-T extinction which occurred between the Cretaceous Period of the Mesozoic Era and the Tertiary Period of the Cenozoic Era - another fundamental break in the geologic time scale that occurred about 65 Ma). In reality, there have been numerous mass extinctions with the Permian one being the worst.
Bottom line... Prior to 250 Ma, there were only reptiles (no dinos). Permian mass extinction 250 Ma. Dinos evolve and rule earth for some 180 Ma. K-T extinction 65 Ma. No more dinos. Big difference.
By the way, the Permian extinction was even worse than the quote above makes it sound. The 70% estimate is only for terrestrial vertebrate species (not nonexistant dinosaurs). One group of terrestrial vertebrates greatly effected by this event were the therapsids - also known as mammal-like reptiles (reptiles which eventually evolved into the mammals). Well over 90% of marine species became extinct as well (think about that for a minute).
Now I can understand non-scientists (and my students) not knowing about the Permian extinction. But a journalist and an editor at a major national news organization writing for the Science & Technology section? I'm not one of those knee-jerk "Fox News sucks" people - hell, I think CNN and MSNBC suck too - but in this case, they do indeed look like morons.
Reminds me of our local newspaper. Once, when we offered a night telescope observation on my Campus open to the public and once when they reported on an event on Campus called Science Olympiad, they confused astronomy with astrology. When confronted with this, the editor basically said "Don't make such a big deal out of this, it was just a typo." No, sorry. Typing "astronony" is a typo. Typing "astrology" is ignorance. To a science person, saying "XX Community College is offering a night astrology observation on Friday" is a glaring error that just jumps off the page. Of course, the paper (like most in this country) carries a daily astrology column but barely ever covers astronomy (or any other science except health-related ones).
Next excerpt...
"Scientists investigating the high incidence of lung cancer in China's Xuan Wei County in Yunnan Province conclude that the problem lies with the coal residents use to heat their homes. That coal was formed by the same 250-million-year-old giant volcanic eruption — termed a supervolcano — that was responsible for the extinction of the dinosaurs. The high silica content of that coal is interacting with volatile organic matter in the soil to cause the unusually high rates of lung cancer."
Coal is not "formed" by volcanic eruptions. Coal is basically buried and compressed plant material. And don't get me started on the term "supervolcano" - it's an invention of science journalists and media-whoring geologists who want to be on TV.
The real story here is actually quite interesting. About 251-250 Ma, huge volumes of basaltic lava erupted in the area that's now Siberia and resulted in an area called the Siberian Traps (traps is derived from a word meaning "steps" because sheet-like lava flows often erode into step-like plateaus). These basalt sheets cover a few million square kilometers - a vast area of the landscape. During the extrusion of this lava, there were also associated pyroclastic eruptions of ash that reached the stratosphere and were spread around the world.
Some of this ash, composed of very fine particles of the mineral quartz (silica), settled into swamps and peat bogs in what's now China. This silica was buried with the plant material and it all formed into coal that's mined today. Chinese laborors burn this coal for fuel in their homes and it releases the silica back into the atmosphere where it's breathed in and seems to cause increased rates of lung cancer.
A neat story. One that Fox News totally screwed up. Wired magazine has a much better story - Chinese coal formed during earth's greatest extinction is deadly.
Monday, January 4, 2010
Picture of the Week - Clove Valley
Photo of the week...
I took this picture during the summer from a location called Cope's Lookout on the Mohonk Mountain House property. Mohonk Mountain House is a beautiful (albeit expensive) resort located on the Shawangunk Ridge in the mid-Hudson Valley.
The Shawangunks (locally pronounced "shon-gums") is a NE-SW trending ridge arising in Rosendale (Ulster County) and running past Port Jervis into NJ/PA on the east side of the Delaware River. On the east side of the Shawangunks is the Wallkill and Hudson River Valleys and on the west side is the Rondout Valley and Catskills. The geology of the Shawangunks is interesting but I'll save that for another post - suffice to say that it's composed of rock (Shawangunk Conglomerate) of a different age than the rocks underlying the valleys on either side of the Ridge.
This view from Cope's Lookout is facing roughly SW along the Ridge. On the left, a bit of the Wallkill and Hudson Valleys can be seen to the SE. On the east side of the ridge are cliffs popular among rock climbers (the "gunks" are actually world-famous for rock climbing). The land surface slopes downward from the tops of these cliffs into Clove Valley in the center of the image. On the other side of Clove Valley, the ground rises up again. The reason Clove Valley exists is because the Shawangunk Conglomerate underlying this valley is folded into a syncline - a downward-sagging fold. Imagine holding a flat sheet of paper between your two hands and pushing your hands toward each other until the sheet of paper buckles downward into a U-shape - the beds of Shawangunk Conglomerate did the same thing here.
Hiking on the rocks on the east (left) side of Clove Valley shows that the layers (beds) of rock are dipping downward toward the west (into Clove Valley). Hiking on the rocks on the west (right) side of Clove Valley shows that the beds of rock are dipping downward toward the east (also into Clove Valley). It's actually possible to hike throughout most of the area visible in this image because the land is owned by the Mohonk Preserve and accessible after paying an entrance fee or having a membership (highly recommended if you live in the area). The land in the distance is part of Lake Minnewaska State Park (also highly recommended for a visit).
Below is a cross-section of the geology of the mid-Hudson Valley from Regional Geology of Southeastern New York State for Teachers and Travelers by J. Bret Bennington of Hofstra University.
See where it says Lake Minnewaska? That's the top of the Shawangunk Ridge and the layer of rock with dots in it is the Shawangunk Conglomerate. Note how it's a bit "wavy" where it's exposed at the surface? Those are folds and one of the downward warps (a syncline in geology) is the Clove Valley! The Shawangunk Ridge is exposed where it is due to a combination of folding and the fact that it's a harder, more resistant rock than the shales under the Wallkill Valley to the east and the limestones (primarily) under the Rondout Valley to the west. The great glacial ice sheets moving down the Hudson Valley during the last ice age (which ended just a few thousand years ago) also played a huge role in shaping the landscape we see today.
The underlying geology obviously affects the present-day shape of the landscape. The geologic history (e.g. glaciation) also clearly affects the present-day shape of the landscape. But, less obviously, the underlying geology can also affect the flora and fauna of the region. I'll discuss the unique ecosystems present on the Shawangunk Ridge at a later date.
I took this picture during the summer from a location called Cope's Lookout on the Mohonk Mountain House property. Mohonk Mountain House is a beautiful (albeit expensive) resort located on the Shawangunk Ridge in the mid-Hudson Valley.
The Shawangunks (locally pronounced "shon-gums") is a NE-SW trending ridge arising in Rosendale (Ulster County) and running past Port Jervis into NJ/PA on the east side of the Delaware River. On the east side of the Shawangunks is the Wallkill and Hudson River Valleys and on the west side is the Rondout Valley and Catskills. The geology of the Shawangunks is interesting but I'll save that for another post - suffice to say that it's composed of rock (Shawangunk Conglomerate) of a different age than the rocks underlying the valleys on either side of the Ridge.
This view from Cope's Lookout is facing roughly SW along the Ridge. On the left, a bit of the Wallkill and Hudson Valleys can be seen to the SE. On the east side of the ridge are cliffs popular among rock climbers (the "gunks" are actually world-famous for rock climbing). The land surface slopes downward from the tops of these cliffs into Clove Valley in the center of the image. On the other side of Clove Valley, the ground rises up again. The reason Clove Valley exists is because the Shawangunk Conglomerate underlying this valley is folded into a syncline - a downward-sagging fold. Imagine holding a flat sheet of paper between your two hands and pushing your hands toward each other until the sheet of paper buckles downward into a U-shape - the beds of Shawangunk Conglomerate did the same thing here.
Hiking on the rocks on the east (left) side of Clove Valley shows that the layers (beds) of rock are dipping downward toward the west (into Clove Valley). Hiking on the rocks on the west (right) side of Clove Valley shows that the beds of rock are dipping downward toward the east (also into Clove Valley). It's actually possible to hike throughout most of the area visible in this image because the land is owned by the Mohonk Preserve and accessible after paying an entrance fee or having a membership (highly recommended if you live in the area). The land in the distance is part of Lake Minnewaska State Park (also highly recommended for a visit).
Below is a cross-section of the geology of the mid-Hudson Valley from Regional Geology of Southeastern New York State for Teachers and Travelers by J. Bret Bennington of Hofstra University.
See where it says Lake Minnewaska? That's the top of the Shawangunk Ridge and the layer of rock with dots in it is the Shawangunk Conglomerate. Note how it's a bit "wavy" where it's exposed at the surface? Those are folds and one of the downward warps (a syncline in geology) is the Clove Valley! The Shawangunk Ridge is exposed where it is due to a combination of folding and the fact that it's a harder, more resistant rock than the shales under the Wallkill Valley to the east and the limestones (primarily) under the Rondout Valley to the west. The great glacial ice sheets moving down the Hudson Valley during the last ice age (which ended just a few thousand years ago) also played a huge role in shaping the landscape we see today.
The underlying geology obviously affects the present-day shape of the landscape. The geologic history (e.g. glaciation) also clearly affects the present-day shape of the landscape. But, less obviously, the underlying geology can also affect the flora and fauna of the region. I'll discuss the unique ecosystems present on the Shawangunk Ridge at a later date.
Climate Change and Scientific Behavior
Just read an interesting article on Climate Change and Scientific Behavior by Diandra Leslie-Pelecky over at Cocktail Party Physics. I feel the same way that Diandra does. As a community college Earth science professor, I teach classes in weather and climate even though my area of expertise is geology (more specifically, structure / tectonics). I'm not, by any stretch of the imagination, a climatologist, yet I have to teach students about global climate change.
Don't get me wrong, I know enough about paleoclimate proxies, stable isotope analysis, solar cycles, natural and anthropogenic CO2 sources, basic atmospheric chemistry, etc. to teach my 100-level course, but I also want to understand the data, assumptions, and models used to predict anthropogenic global warming over the next few decades. I would like to be able to confidently discuss the effects of warming - sea level rise, changes in oceanic thermohaline circulation. glacial melting, etc.
The problem is that the issue of anthropogenic global warming (AGW) appears to have become heavily politicized. Simplistically, Democrats "believe" in AGW and Republicans do not. The issue's "settled." Anyone who questions any aspect of AGW is a GW "denier." Scientists who publish studies critical of AGW need to be silenced and the journals who publish those papers need to be punished.
Silly me, I thought science wasn't about "belief," openness was an essential part of the process, and a little skepticism was a good thing. So, while I certainly think the evidence indicates AGW is real, the other bullshit surrounding the issue disturbs me. I'm guess I'm just a naive idealist. It makes me want to shy away from the issue completely. Just teach the kids the basics of chemistry, physics, etc. necessary to understand the arguments and then hand them the latest IPCC report. Problem is that some of them (the smart ones, at least) then want to know what I think. Damned if I know.
Don't get me wrong, I know enough about paleoclimate proxies, stable isotope analysis, solar cycles, natural and anthropogenic CO2 sources, basic atmospheric chemistry, etc. to teach my 100-level course, but I also want to understand the data, assumptions, and models used to predict anthropogenic global warming over the next few decades. I would like to be able to confidently discuss the effects of warming - sea level rise, changes in oceanic thermohaline circulation. glacial melting, etc.
The problem is that the issue of anthropogenic global warming (AGW) appears to have become heavily politicized. Simplistically, Democrats "believe" in AGW and Republicans do not. The issue's "settled." Anyone who questions any aspect of AGW is a GW "denier." Scientists who publish studies critical of AGW need to be silenced and the journals who publish those papers need to be punished.
Silly me, I thought science wasn't about "belief," openness was an essential part of the process, and a little skepticism was a good thing. So, while I certainly think the evidence indicates AGW is real, the other bullshit surrounding the issue disturbs me. I'm guess I'm just a naive idealist. It makes me want to shy away from the issue completely. Just teach the kids the basics of chemistry, physics, etc. necessary to understand the arguments and then hand them the latest IPCC report. Problem is that some of them (the smart ones, at least) then want to know what I think. Damned if I know.
Subscribe to:
Posts (Atom)