Atoms and Molecules: Using magnetic toys as inspiration, researchers tease out structures of self-assembled clusters
"Most people are familiar with entropy as a measure of 'disorder', but the most useful definition of entropy is simply the number of different ways a bunch of particles can arrange themselves."
My understanding of molecular physics is not very sophisticated. I find this fascinating nonetheless. We're always working towards a fundamental understanding of how the world works.
Friday, January 29, 2010
Thursday, January 28, 2010
Running barefoot blunts foot's force
“From an evolutionary perspective, it’s normal and, if done properly, it is very fun and comfortable. We evolved to run barefoot.”
Duh!
Monarch butterflies reveal a novel way in which animals sense Earth's magnetic field
Monarch butterflies reveal a novel way in which animals sense Earth's magnetic field
"Because the butterfly Cry2 protein is closely related to the one in vertebrates, like that found in birds which use the Earth's magnetic field to aid migration," states Dr. Reppert, "the finding provides the first genetic evidence that a vertebrate-like Cry can function as a magnetoreceptor."
So it's possible that the ability of monarchs and birds to orient themselves during migration are a result of convergent evolution and that the adaptations allowing them to do so originate from the same gene or group of genes. Amazing.
"Because the butterfly Cry2 protein is closely related to the one in vertebrates, like that found in birds which use the Earth's magnetic field to aid migration," states Dr. Reppert, "the finding provides the first genetic evidence that a vertebrate-like Cry can function as a magnetoreceptor."
So it's possible that the ability of monarchs and birds to orient themselves during migration are a result of convergent evolution and that the adaptations allowing them to do so originate from the same gene or group of genes. Amazing.
Wednesday, January 27, 2010
In bats and whales, convergence in echolocation ability runs deep
In bats and whales, convergence in echolocation ability runs deep
"The natural world is full of examples of species that have evolved similar characteristics independently, such as the tusks of elephants and walruses," said Stephen Rossiter of the University of London, an author on one of the studies. "However, it is generally assumed that most of these so-called convergent traits have arisen by different genes or different mutations. Our study shows that a complex trait -- echolocation -- has in fact evolved by identical genetic changes in bats and dolphins."
Another example of what I like to call the "singularity of life." Amazingly, the incredible diversity of life on this planet is all based upon the same genetic underpinnings. Every single organism that we know of, from bacteria to bonobos, uses DNA as the blueprint for function and development. The DNA of every organism is composed of two sugar-phosphate "backbones" joined by four chemical bases (adenine, thymine, cytosine and guanine) to form a double helix. It's as if the music of life were composed using jjust four notes. The same four notes yield algae, alligators, and arthropods. Amazing.
Nature is conservative. Energy is precious and not wasted. Adaptations that work are not lightly discarded. So strategies that work pop up again and again, in organisms that are related really only in the respect that they both have DNA. Cephalopods and vertebrates evolved spectacular optical organs (there is still much debate as to whether the eye evolved just once or on many different occasions - my bet is on multiple occasions). Bats and birds both fly. Bats and dolphins both echolocate. It remains to be seen whether all instances of convergence share specific groups of genes in similar fashion to the echolocation described in this article, but we can be assured we haven't heard the last of this subject.
Apple vs. Obama
Which is more important: politics or technology? An excellent article spanning all the ways that cutting-edge technologies are affecting our lives both as Americans and as global citizens. Saletan is one one of my favorite science journalists.
Tuesday, January 26, 2010
Frozen light stays fresh longer
Light, water, and gravity are the three of the most fascinating (and confounding) physical science topics. As long as we've been studying them and as important as they are to life as we know it, it always surprises me how little we know about them and how much mystery surrounds them.
Bat echolocation: 3-D imaging differentiates how various bats generate biosonar signals
Bat echolocation: 3-D imaging differentiates how various bats generate biosonar signals
It's surprising to learn that bats can echolocate in different ways. First of all, not all bats echolocate, some are frugivorous, some are nectarivores. This article focuses on the use of micro-CT 3d imaging do differentiate physiological different between bats that use tongue clicks to echolocate and those that are physiologically adapted to practice laryngeal echolocation. Amazingly, it is now suspected that the use of echolocation has evolved more than once in bats. Bats that echolocate are not necessarily closely related to one another. Just another example of the singularity of life.
It's surprising to learn that bats can echolocate in different ways. First of all, not all bats echolocate, some are frugivorous, some are nectarivores. This article focuses on the use of micro-CT 3d imaging do differentiate physiological different between bats that use tongue clicks to echolocate and those that are physiologically adapted to practice laryngeal echolocation. Amazingly, it is now suspected that the use of echolocation has evolved more than once in bats. Bats that echolocate are not necessarily closely related to one another. Just another example of the singularity of life.
Monday, January 25, 2010
The Next Big Quake? | Foreign Policy
The Next Big Quake? | Foreign Policy
The effects of a 6.5 earthquake at the New Madrid fault are seen above. Numerals are based on the Mercalli scale. The effects in KC would be as follows:
Felt indoors by many people, outdoors by few people during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rock noticeably. Dishes and windows rattle alarmingly.
However, the fault is capable of producing much larger earthquakes, and has done so in the past. One can just imagine the effects that a large (>7.5 on Richter scale) earthquake would have on Memphis and St. Louis. There are close to 4 million people in the greater metropolitan areas of those two cities combined.
The effects of a 6.5 earthquake at the New Madrid fault are seen above. Numerals are based on the Mercalli scale. The effects in KC would be as follows:
Felt indoors by many people, outdoors by few people during the day. At night, some awakened. Dishes, windows, doors disturbed; walls make cracking sound. Sensation like heavy truck striking building. Standing motor cars rock noticeably. Dishes and windows rattle alarmingly.
However, the fault is capable of producing much larger earthquakes, and has done so in the past. One can just imagine the effects that a large (>7.5 on Richter scale) earthquake would have on Memphis and St. Louis. There are close to 4 million people in the greater metropolitan areas of those two cities combined.
Some mouse sperm can identify, and even cooperate with, its brethren
Some mouse sperm can identify, and even cooperate with, its brethren
This is crazy! Apparently in some promiscuous species of deer mice, sperm from the same male can recognize and cluster together. Theoretically this increases the chance of that male's sperm fertilizing the egg. Since only one sperm cell fertilizes the eggs, the rest are exhibiting altruistic behavior, you know "taking one for the team."
Promiscuity can be a selective force in evolution, as evidenced by this study on the evolutionary origin human penis morphology. Interesting stuff.
This is crazy! Apparently in some promiscuous species of deer mice, sperm from the same male can recognize and cluster together. Theoretically this increases the chance of that male's sperm fertilizing the egg. Since only one sperm cell fertilizes the eggs, the rest are exhibiting altruistic behavior, you know "taking one for the team."
Promiscuity can be a selective force in evolution, as evidenced by this study on the evolutionary origin human penis morphology. Interesting stuff.
Friday, January 22, 2010
Last Decade Was Warmest on Record, 2009 One of Warmest Years, NASA Research Finds
"The contiguous 48 states cover only 1.5 percent of the world area, so the United States' temperature does not affect the global temperature much," Hansen said."
Global warming skeptics (especially those with political bias) are quick to remark on how cool the past year was in the United States. As indicated by the quote, though, the US represents a small fraction of the temperature values in the world. Here is what the article says about the cooler than normal temps in the US:
"High air pressures from the Arctic decreased the east-west flow of the jet stream, while increasing its tendency to blow from north to south. The result was an unusual effect that caused frigid air from the Arctic to rush into North America and warmer mid-latitude air to shift toward the north. This left North America cooler than normal, while the Arctic was warmer than normal."
At the risk of oversimplifying, I suppose it's possible that warming in the arctic is responsible for cooler temps in the US given that high air pressures can result from fair weather. I find climate science fascinating in the same way that all science fascinates me: the more we know, it seems the less we know. Each answer to a question poses a multitude of other questions. It can be mind numbing to the general public, especially when politicians attempt to make policy using science (I find politicians as a group to be some of the most scientifically illiterate and ignorant).
When I talk to my students about climate change, I advice them that the scientific consensus is clear: global warming is a real phenomena. However, the long-term effects of global warming are essentially unknown. Science can make predictions. It can't tell the future. Most of our climate predictions are based upon computer modeling and right now computer models don't deal with clouds very well. If we can't model clouds, we can't reliably model climate.
Global warming skeptics (especially those with political bias) are quick to remark on how cool the past year was in the United States. As indicated by the quote, though, the US represents a small fraction of the temperature values in the world. Here is what the article says about the cooler than normal temps in the US:
"High air pressures from the Arctic decreased the east-west flow of the jet stream, while increasing its tendency to blow from north to south. The result was an unusual effect that caused frigid air from the Arctic to rush into North America and warmer mid-latitude air to shift toward the north. This left North America cooler than normal, while the Arctic was warmer than normal."
At the risk of oversimplifying, I suppose it's possible that warming in the arctic is responsible for cooler temps in the US given that high air pressures can result from fair weather. I find climate science fascinating in the same way that all science fascinates me: the more we know, it seems the less we know. Each answer to a question poses a multitude of other questions. It can be mind numbing to the general public, especially when politicians attempt to make policy using science (I find politicians as a group to be some of the most scientifically illiterate and ignorant).
When I talk to my students about climate change, I advice them that the scientific consensus is clear: global warming is a real phenomena. However, the long-term effects of global warming are essentially unknown. Science can make predictions. It can't tell the future. Most of our climate predictions are based upon computer modeling and right now computer models don't deal with clouds very well. If we can't model clouds, we can't reliably model climate.
Thursday, January 21, 2010
Canine evolution
More research into canine evolution:
"a Collie has a skull shape that is more different from that of a Pekingese than the skull shape of the cat is from that of a walrus."
Essentially, human selection has created a higher diversity in skull morphology within canine than millions of years of natural selection created in the order Carnivora. Genes are amazing in their plasticity and in their perseverance.
"a Collie has a skull shape that is more different from that of a Pekingese than the skull shape of the cat is from that of a walrus."
Essentially, human selection has created a higher diversity in skull morphology within canine than millions of years of natural selection created in the order Carnivora. Genes are amazing in their plasticity and in their perseverance.
New theory on the origin of primates
New theory on the origin of primates
This theory proposes plate tectonics as a major factor in the divergence of primate species.
"Divergence between strepsirrhines (lemurs and lorises) and haplorhines (tarsiers and anthropoids) is correlated with intense volcanic activity on the Lebombo Monocline in Africa about 180 million years ago. The lemurs of Madagascar diverged from their African relatives with the opening of the Mozambique Channel (160 million years ago), while New and Old World monkeys diverged with the opening of the Atlantic about 120 million years ago."
This study would seem to support the theory of punctuated equilibrium. Adaptation acquisition (genetic or behavioral) requires a forcing mechanism. That is, adaptation doesn't occur in the absence of some stressing factor (competition, climate change, geographic separation, etc.) It seems likely to me that competition and predation, for instance, provides for a constant stressor as a mechanism for a more gradual evolutio (think elk and wolves or trees competing for sunlight in a rain forest). In addition, there are catastrophic evolutionary events (continents colliding or separating) that give rise to an evolutionary history that is more punctuated in nature.
It's tempting to think that evolution is analogous to technological advancement, the improvement of a design through constant trial and error, becoming more sophisticated through time. I try to teach my students otherwise, though. We tend to think of the most sophisticated animals as the most "highly evolved." Primates, marine mammals, and orchids are highly sophisticated. I teach that biological sophistication is not the goal of evolution. The goal of evolution is the persistence of genes through time, and success is measured by the ability of genes to perpetuate.
One of my favorite examples of the is the tapeworm. Its hard to argue that tapeworms are physiologically sophisticated and yet they are very highly evolved. Especially when you consider their evolutionary history with humans.
This theory proposes plate tectonics as a major factor in the divergence of primate species.
"Divergence between strepsirrhines (lemurs and lorises) and haplorhines (tarsiers and anthropoids) is correlated with intense volcanic activity on the Lebombo Monocline in Africa about 180 million years ago. The lemurs of Madagascar diverged from their African relatives with the opening of the Mozambique Channel (160 million years ago), while New and Old World monkeys diverged with the opening of the Atlantic about 120 million years ago."
This study would seem to support the theory of punctuated equilibrium. Adaptation acquisition (genetic or behavioral) requires a forcing mechanism. That is, adaptation doesn't occur in the absence of some stressing factor (competition, climate change, geographic separation, etc.) It seems likely to me that competition and predation, for instance, provides for a constant stressor as a mechanism for a more gradual evolutio (think elk and wolves or trees competing for sunlight in a rain forest). In addition, there are catastrophic evolutionary events (continents colliding or separating) that give rise to an evolutionary history that is more punctuated in nature.
It's tempting to think that evolution is analogous to technological advancement, the improvement of a design through constant trial and error, becoming more sophisticated through time. I try to teach my students otherwise, though. We tend to think of the most sophisticated animals as the most "highly evolved." Primates, marine mammals, and orchids are highly sophisticated. I teach that biological sophistication is not the goal of evolution. The goal of evolution is the persistence of genes through time, and success is measured by the ability of genes to perpetuate.
One of my favorite examples of the is the tapeworm. Its hard to argue that tapeworms are physiologically sophisticated and yet they are very highly evolved. Especially when you consider their evolutionary history with humans.
Wednesday, January 20, 2010
Science in Avatar
I saw Avatar on Christmas Eve. I now know that I was probably feverish and in the midst of contracting walking pneumonia when I saw it so my recollections are a bit hazy. I did geek out on the science aspects of the movie though. The creation of an entirely novel world must be exhilarating given today's CGI technology.
In many ways, the organisms of Pandora exhibit the kind of shared genetic ancestry that I have been thinking a lot about while working my way through Dawkins' The Ancestor's Tale. Lots of blue organisms, organisms that light up, flighted reptilian thingys, animals breathing through their chests, predator/prey relationships, etc. Most of this fictitious biology seems well thought out. Somehow the Na'vi are bipedal humanoids that breath through their flattened noses, though. Somehow, a hexapedal blue cat woman that breathes through her chest would not be as cool, I guess
The physics of the movie seem a little less believable, however. What's up with the floating rock islands?
Tuesday, January 19, 2010
Dog genome researchers track paw prints of selective breeding
Dog genome researchers track paw prints of selective breeding
More evidence of shared genetic history. Genes in the same location on mouse, human, and dog genomes have similar functions. Mutations in these genes yield similar phenotypic results. A mutation of a gene involved in skin appearance gives the shar-pei wrinkly skin. A mutation in that same gene in humans yields excessively wrinkly skin. Fascinating.
The "evolution" of dog breeds provides an interesting study of evolutionary concepts. It's amazing to think how much breeds have diverged in 10,000 years, while maintaining their cohesion as a single species. A Great Dane and a chihuahua are the same species! That means they can reproduce and yield viable offspring.
Different breeds come from selective breeding of dogs by humans for certain traits. These traits allowed dog to specific jobs. Having worked in a pet store, I can say that more people need to pay attention to the history of their favorite breed before purchasing a puppy. Australian cattle dogs are cute, but make poor pets for city-dwellers because they were bred to be on the move herding every day. When I was in middle school, my family helped round up and brand calves on a ranch in norther New Mexico. The ranch had a pair of ACD's named Ding and Dong that helped herd. Watching those dogs do their job was a pleasure - they were all business. I think the same can be said for watching for watching any herding, working or hunting breed do its job.
However, to achieve consistent breed characteristics (coat length, coat thickness, pointing, tracking, size, temperament, etc., etc.) dogs have to be inbred. This means fathers bred to daughters, mothers to sons, brothers to sisters, etc. This process emphasizes and accentuates both positive and negative genetic characteristics. This is why purebred dogs have higher incidences of genetic disorders and predispositions toward certain health problems (hip displasia, eye problems, etc.)
That's all for now. I love thinking about domestic animals and evolution (as did Darwin, by the way) so I'll talk more about this in the future, I'm sure.
More evidence of shared genetic history. Genes in the same location on mouse, human, and dog genomes have similar functions. Mutations in these genes yield similar phenotypic results. A mutation of a gene involved in skin appearance gives the shar-pei wrinkly skin. A mutation in that same gene in humans yields excessively wrinkly skin. Fascinating.
The "evolution" of dog breeds provides an interesting study of evolutionary concepts. It's amazing to think how much breeds have diverged in 10,000 years, while maintaining their cohesion as a single species. A Great Dane and a chihuahua are the same species! That means they can reproduce and yield viable offspring.
Different breeds come from selective breeding of dogs by humans for certain traits. These traits allowed dog to specific jobs. Having worked in a pet store, I can say that more people need to pay attention to the history of their favorite breed before purchasing a puppy. Australian cattle dogs are cute, but make poor pets for city-dwellers because they were bred to be on the move herding every day. When I was in middle school, my family helped round up and brand calves on a ranch in norther New Mexico. The ranch had a pair of ACD's named Ding and Dong that helped herd. Watching those dogs do their job was a pleasure - they were all business. I think the same can be said for watching for watching any herding, working or hunting breed do its job.
However, to achieve consistent breed characteristics (coat length, coat thickness, pointing, tracking, size, temperament, etc., etc.) dogs have to be inbred. This means fathers bred to daughters, mothers to sons, brothers to sisters, etc. This process emphasizes and accentuates both positive and negative genetic characteristics. This is why purebred dogs have higher incidences of genetic disorders and predispositions toward certain health problems (hip displasia, eye problems, etc.)
That's all for now. I love thinking about domestic animals and evolution (as did Darwin, by the way) so I'll talk more about this in the future, I'm sure.
Friday, January 15, 2010
Heart animations
Today we dissected sheep hearts in my 6th grade science class. I promised the students I would post links to some of the heart animations that I showed them. Here is a good narrated animation that moves slowly and identifies all the basic chambers, valves, veins and arteries. This is simplifies two dimensional animation depicting blood movement through the heart. And finally this is a fantastic 3d animation that allows you to choose the level of transparency while providing views from multiple perspectives. Some really fantastic animations that demonstrate what an amazing organ the heart really is!
The future of food
This article reminds of the science fiction series Chung Kuo by author David Wingrove. I wonder what PETA thinks about growing meat in a dish. You are what you eat? Garbage in, garbage out?
LOL
LOL
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