”Romer (Dec. 28, 1894 – Nov. 5, 1973) was director of the Museum of Comparative Zoology at Harvard University until his retirement in 1961 and was one the singularly most influential vertebrate paleontologists of the 20th Century. His work ranged over virtually every conceivable subject within that field, although it was the osteology and taxonomy of the therapsids and other proto-mammals which was nearest his heart.
In addition to this work, Romer was acutely interested in the origin and initial adaptive radiation of tetrapods, and his work became the basis for a theory of tetrapod origins which was canon until the description of Acanthostega gunnari by Clack & Coates in the 1990s. Romer was ahead of his time in his defense of monophyly of Dinosauria though he did feel that Theropoda was not ancestral to birds.” link from EvoWiki.org
Romer’s book, Vertebrate Paleontology (1966), was for many years THE textbook on VP and is still well worth picking up. One of Romer’s students, Bob Carroll, wrote an updated version entitled, ‘Vertebrate Paleontology and Evolution’, in 1987. image
Senin, 27 Desember 2010
Plant-Eating Theropods
Herbivorous ecomorphology and specialization patterns in theropod dinosaur evolution. 2010. L.E. Zanno & P. J. Makovicky. PNAS, published ahead of print December 20.
Fortunately a small percentage of these species also preserve clear-cut evidence of diet with their skeletal remains. Fossilized dinosaur dung, stomach contents, tooth marks, the presence of stones within the stomach that serve as a gastric mill for digesting vegetation, and even two dinosaur species preserved locked in the throes of combat all provide a direct window on diet. After collecting dietary data for almost 100 coelurosaur species, the researchers found that almost two dozen anatomical features could be linked to direct evidence of herbivory including a toothless beak.
Because plant eating was found to be so widespread in Coelurosauria, the hypercarnivorous habits of T. rex and other meat eating coelurosaurs like Velociraptor should be viewed more as the exception than the rule.
The resesrchers also found that a toothless beak only evolved in lineages known to have had a gastric mill for grinding plants. In lineages where a gastric mill is not yet known, such as the bizarre, sickle-clawed therizinosaurs, the species retain teeth at the back of the mouth for shredding plant material.
Because ceolurosaurian dinosaurs include the closest extinct relatives of birds, understanding their biology is also extremely important to understanding how, why, and under what conditions birds evolved and first took flight. link.
Dear Field Museum Press People: Surely the FM has put out a press release since last August. I'd suggest updating your press page, especially when you provide links to out of date sites.
Scientists have used statistical analyses to determine that for 90 species of theropod dinosaurs, especially the most bird-like dinosaurs—known as coelurosaurs—plant eating was a common way of life.Unlike Tyrannosaurus rex with its bone-crunching teeth, many coelurosaurian dinosaurs have peg-like teeth at the front of the mouth or no teeth at all so determining their diet has been a challenge.
Fortunately a small percentage of these species also preserve clear-cut evidence of diet with their skeletal remains. Fossilized dinosaur dung, stomach contents, tooth marks, the presence of stones within the stomach that serve as a gastric mill for digesting vegetation, and even two dinosaur species preserved locked in the throes of combat all provide a direct window on diet. After collecting dietary data for almost 100 coelurosaur species, the researchers found that almost two dozen anatomical features could be linked to direct evidence of herbivory including a toothless beak.
Because plant eating was found to be so widespread in Coelurosauria, the hypercarnivorous habits of T. rex and other meat eating coelurosaurs like Velociraptor should be viewed more as the exception than the rule.
The resesrchers also found that a toothless beak only evolved in lineages known to have had a gastric mill for grinding plants. In lineages where a gastric mill is not yet known, such as the bizarre, sickle-clawed therizinosaurs, the species retain teeth at the back of the mouth for shredding plant material.
Because ceolurosaurian dinosaurs include the closest extinct relatives of birds, understanding their biology is also extremely important to understanding how, why, and under what conditions birds evolved and first took flight. link.
Dear Field Museum Press People: Surely the FM has put out a press release since last August. I'd suggest updating your press page, especially when you provide links to out of date sites.
Voyage of The Beagle Began Today
From Today In Science History:
In 1831, Charles Darwin set sail from Plymouth harbour on his voyage of scientific discovery aboard the HMS Beagle, a British Navy ship. The Captain Robert FitzRoy was sailing to the southern coast of South America in order to complete a government survey. Darwin had an unpaid position as the ship's naturalist, at age 22, just out of university.
Originally planned to be at sea for two years, the voyage lasted five years, making stops in Brazil, the Galapogos Islands, and New Zealand. From the observations he made and the specimens he collected on that voyage, Darwin developed his theory of biological evolution through natural selection, which he published 28 years after the Beagle left Plymouth.
In 1831, Charles Darwin set sail from Plymouth harbour on his voyage of scientific discovery aboard the HMS Beagle, a British Navy ship. The Captain Robert FitzRoy was sailing to the southern coast of South America in order to complete a government survey. Darwin had an unpaid position as the ship's naturalist, at age 22, just out of university.
Originally planned to be at sea for two years, the voyage lasted five years, making stops in Brazil, the Galapogos Islands, and New Zealand. From the observations he made and the specimens he collected on that voyage, Darwin developed his theory of biological evolution through natural selection, which he published 28 years after the Beagle left Plymouth.
Kamis, 23 Desember 2010
Triassic Extinction Recovery Took 10 Million Years
The Luoping biota: exceptional preservation, and new evidence on the Triassic recovery from end-Permian mass extinction. 2010. Shi-xue Hu, et al. Proc. Royal Soc. B, published online before print Dec. 23.
New fossil site in China shows long recovery of life from the largest extinction in Earth’s history.
Some 250 million years ago, at the end of the Permian, life was all but wiped out during a sustained period of massive volcanic eruption and devastating global warming. Only one in ten species survived, and these formed the basis for the recovery of life in the subsequent time period, called the Triassic. The new fossil site – at Luoping in Yunnan Province – provides a new window on that recovery, and indicates that it took about 10 million years for a fully-functioning ecosystem to develop.
‘The Luoping site dates from the Middle Triassic and contains one of the most diverse marine fossil records in the world,’ said Professor Benton. ‘It has yielded 20,000 fossils of fishes, reptiles, shellfish, shrimps and other seabed creatures. We can tell that we’re looking at a fully recovered ecosystem because of the diversity of predators, most notably fish and reptiles. It’s a much greater diversity than what we see in the Early Triassic – and it’s close to pre-extinction levels.’
Reinforcing this conclusion is the complexity of the food web, with the bottom of the food chains dominated by species typical of later Triassic marine faunas – such as crustaceans, fishes and bivalves – and different from preceding ones.
Just as important is the ‘debut’ of top predators – such as the long-snouted bony fish Saurichthys, the ichthyosaur Mixosaurus, the sauropterygian Nothosaurus and the prolacertiform Dinocephalosaurus – that fed on fishes and small predatory reptiles. link.
New fossil site in China shows long recovery of life from the largest extinction in Earth’s history.
Some 250 million years ago, at the end of the Permian, life was all but wiped out during a sustained period of massive volcanic eruption and devastating global warming. Only one in ten species survived, and these formed the basis for the recovery of life in the subsequent time period, called the Triassic. The new fossil site – at Luoping in Yunnan Province – provides a new window on that recovery, and indicates that it took about 10 million years for a fully-functioning ecosystem to develop.
‘The Luoping site dates from the Middle Triassic and contains one of the most diverse marine fossil records in the world,’ said Professor Benton. ‘It has yielded 20,000 fossils of fishes, reptiles, shellfish, shrimps and other seabed creatures. We can tell that we’re looking at a fully recovered ecosystem because of the diversity of predators, most notably fish and reptiles. It’s a much greater diversity than what we see in the Early Triassic – and it’s close to pre-extinction levels.’
Reinforcing this conclusion is the complexity of the food web, with the bottom of the food chains dominated by species typical of later Triassic marine faunas – such as crustaceans, fishes and bivalves – and different from preceding ones.
Just as important is the ‘debut’ of top predators – such as the long-snouted bony fish Saurichthys, the ichthyosaur Mixosaurus, the sauropterygian Nothosaurus and the prolacertiform Dinocephalosaurus – that fed on fishes and small predatory reptiles. link.
Rabu, 22 Desember 2010
Premiered This Day (1933): Son of Kong
With the fantastic success of “King Kong”, RKO tried to cash in by rushing this sequel into production and releasing it within the same year (1933). It did not do nearly as well, but animator Willis O’Brien did manage to bring some of the same charm to the big white ape that he did to Kong.
Died This Day: Kenneth Tobey
Tobey (Mar. 23, 1917 - Dec. 22, 2002) made a career of playing “take charge, men of authority”, such as Capt. Hendry in Howard Hawkes, “The Thing From Another World” (1951), and just about every TV series throughout the 60’s and 70’s. More than a few of his appearances were in SF stories, and he played Col. Jack Evans in The Beast from 20,000 Fathoms (1953).
Discovered This Day: 1st Living Coelacanth
From Today In Science History:
In 1938, a coelacanth, a primitive fish thought extinct, was discovered. Marjorie Courtenay-Latimer was curator of the museum in the port town of East London, northeast of Cape Town, South Africa, and always interested in seeing unusual specimens. Hendrik Goosen, captain of the trawler Nerine, called her to see his catch of the day before, made at about 70-m depth, off the Chalumna River southwest of East London. She spotted an unusual 5-ft fish in his "trash" fish pile. It was pale mauvy-blue with iridescent silver markings. She sent a sketch to Dr J.L.B. Smith, a senior lecturer in chemistry from Rhodes University in Grahamstown for identification. It was hailed as the zoological discovery of the century and equated to finding a living dinosaur!
In 1938, a coelacanth, a primitive fish thought extinct, was discovered. Marjorie Courtenay-Latimer was curator of the museum in the port town of East London, northeast of Cape Town, South Africa, and always interested in seeing unusual specimens. Hendrik Goosen, captain of the trawler Nerine, called her to see his catch of the day before, made at about 70-m depth, off the Chalumna River southwest of East London. She spotted an unusual 5-ft fish in his "trash" fish pile. It was pale mauvy-blue with iridescent silver markings. She sent a sketch to Dr J.L.B. Smith, a senior lecturer in chemistry from Rhodes University in Grahamstown for identification. It was hailed as the zoological discovery of the century and equated to finding a living dinosaur!
“December 22, 1938, Captain Goosen and the Nerine put into East London harbour with the usual catch of sharks, rays, starfish and rat-tail fish. But there was one unusual fish amongst the catch that had been caught in about 70 meters, near the mouth of the Chalumna River. Once ashore Captain Goosen left word at the Museum that there were several specimens at the ship for Miss Latimer. At first she said that she was too busy because she was hard at work cleaning and articulating the fossil reptile bones collected from Tarkastad. But as it was so near Christmas time she decided to go and wish the crew a “Happy Christmas” and took a taxi to the docks. There, attracted by a blue fin amid the pile of sharks, she found a magnificent fish. She and her assistant put it in a bag and persuaded a reluctant taxi driver to take it to the museum in the boot of the car. It measured 150 cm and weighed 57.5 kg. From its hard bony scales with sharp, prickly spines and paired fins looking rather like legs, she knew that it must be some kind of primitive fish.Learn more about Latimeria chalumnae at the Australian Museum fish web page.
But her greatest problem was to preserve it until it could be identified. It was extremely hot, the fish, was too big to go into a bath and she could not find any organization willing to store it in a freezer. Although she was told by experts that it was only a type of rock cod and that she was making a fuss about nothing, she persisted in her attempts to save the fish for science. At first it was wrapped in cloths soaked in formalin but eventually, on the 26th, Mr. Center, a taxidermist, skinned it. Unfortunately the internal organs were thrown away. Marjorie went home disappointed and worried that she had not saved all the soft parts. What she had done, however, was to write immediately to her friend, JLB Smith, and send him her famous sketch of the strange fish.”
Miss Courtenay-Latimer's sketch of the first coelacanth which she posted to JLB Smith.
Minggu, 19 Desember 2010
Born This Day: Richard Leakey
From Today In Science History:
Leakey is a Kenyan physical anthropologist, paleontologist and second of three sons of noted anthropologists Louis Leakey and Mary Leakey. At an early age, he decided he wanted nothing to do with paleoanthropology and started a expedition business. In 1964, he led an expedition to a fossil site which sparked his interest in paleontology. Since then he has been responsible for extensive fossil finds of human ancestral forms in East Africa, including a Homo habilis skull found in 1972, and a Homo erectus skull found in 1975.
His discoveries showed that man's ancestors used tools, which shows intelligence, and lived in eastern Africa at least 3 million years ago - almost doubling the previously accepted age of human origins.
Learn more about The Leakey Foundation HERE.
Sabtu, 18 Desember 2010
Geminiraptor, Oldest Troodontid
A New Troodontid Theropod Dinosaur from the Lower Cretaceous of Utah. 2010. P. Senter, et al. PLoS ONE 5(12): e14329, published Dec. 15.
Most troodontid dinosaurs from North America are dated to 72-75 million years ago. Geminiraptor, at about 125 million years of age, is easily the oldest. The incomplete upper jaw inflated by a large and unique air sack readily identifies the fossil as belonging to a new species of troodontid.
Comparison of the maxilla of Geminiraptor suarezarum to those of other paravians.
Geminiraptor, meaning "Twin Predatory Thief of the Suarezes" is named in honor of Marina and Selina Suarez, graduate students from Temple University in Philadelphia, PA.
Geminiraptor suarezarum, found on BLM lands near Green River, UT, is the oldest reported "raptor-like" troodontid dinosaur in North America (125 million years old).Troodontid dinosaurs like Geminiraptor are "raptor-like" dinosaurs that are often credited with being more intellectually advanced. In fact, in 1982 an imaginative intelligent troodontid "dinosauroid" was proposed by Dale Russell of the National Museum Canada, as the logical consequence if dinosaurs had not gone extinct. This fantastic reconstruction has been criticized as being too anthropomorphic, but was based on the fact that the troodontid braincase was as much as six times larger than other dinosaurs.
Most troodontid dinosaurs from North America are dated to 72-75 million years ago. Geminiraptor, at about 125 million years of age, is easily the oldest. The incomplete upper jaw inflated by a large and unique air sack readily identifies the fossil as belonging to a new species of troodontid.
Comparison of the maxilla of Geminiraptor suarezarum to those of other paravians.
Geminiraptor, meaning "Twin Predatory Thief of the Suarezes" is named in honor of Marina and Selina Suarez, graduate students from Temple University in Philadelphia, PA.
Died This Day: Sir Richard Owen
From Today In Science History:
Owen (July 20, 1804 – Dec. 18, 1892) was an English anatomist and paleontologist who is remembered for his contributions to the study of fossil animals and for his strong opposition to the views of Charles Darwin.
He coined the word "Dinosaur" meaning "terrible reptile" (1842). Owen synthesized French anatomical work, especially from Cuvier and Geoffroy, with German transcendental anatomy. He gave us many of the terms still used today in anatomy and evolutionary biology, including "homology". In 1856, he was appointed Superintendent of the British Museum (Natural History).
Owen (July 20, 1804 – Dec. 18, 1892) was an English anatomist and paleontologist who is remembered for his contributions to the study of fossil animals and for his strong opposition to the views of Charles Darwin.
He coined the word "Dinosaur" meaning "terrible reptile" (1842). Owen synthesized French anatomical work, especially from Cuvier and Geoffroy, with German transcendental anatomy. He gave us many of the terms still used today in anatomy and evolutionary biology, including "homology". In 1856, he was appointed Superintendent of the British Museum (Natural History).
Died This Day: Jean-Baptiste de Monet, Chevalier de Lamarck
From Today in Science History:
Lamarck (Aug.1, 1744 – Dec. 18, 1829) waa a pioneer French biologist who is noted for his speculations about the evolution of living things, particularly his theory that acquired traits are inheritable (such as giraffes who, he said, through stretching to reach tall trees, make their necks longer, and then pass on longer necks to their offspring.) This Lamarckism idea is controverted by Darwinian theory.
He published a flora of France (1778) and a system of classification for invertebrate animals, published in his Histoire naturelle des animaux sans vertebres (7 vols, 1815-22). In 1809 Lamarck published his theory of evolution (in Philosophie zoologique). Lamarck's speculations about the physical and natural world found little favour among his contemporaries and he died blind and in poverty.
From info on Lamarck from The Victorian Web.
Lamarck (Aug.1, 1744 – Dec. 18, 1829) waa a pioneer French biologist who is noted for his speculations about the evolution of living things, particularly his theory that acquired traits are inheritable (such as giraffes who, he said, through stretching to reach tall trees, make their necks longer, and then pass on longer necks to their offspring.) This Lamarckism idea is controverted by Darwinian theory.
He published a flora of France (1778) and a system of classification for invertebrate animals, published in his Histoire naturelle des animaux sans vertebres (7 vols, 1815-22). In 1809 Lamarck published his theory of evolution (in Philosophie zoologique). Lamarck's speculations about the physical and natural world found little favour among his contemporaries and he died blind and in poverty.
From info on Lamarck from The Victorian Web.
Died This Day: Theodosius Dobzhansky
From Today In Science History:
Dobzhansky (Jan. 25, 1900 – Dec. 18, 1975) was an Ukrainian-American geneticist and evolutionist whose work had a major influence on 20th-century thought and research on genetics and evolutionary theory. He made the first significant synthesis of Charles Darwin's theory of evolution with Gregor Mendel's theory of genetics in his book Genetics and the Origin of Species (1937).
From 1918 his research gave experimental evidence that genes could vary far more than geneticists had previously believed. Thus, successful species tend to have a wide variety of genes that, while redundant in its present environment, do provide a species as a whole with genetic diversity. Such diversity enables the species to adapt effectively to changes in the surrounding environment - the basis for modern evolutionary theory.
Dobzhansky (Jan. 25, 1900 – Dec. 18, 1975) was an Ukrainian-American geneticist and evolutionist whose work had a major influence on 20th-century thought and research on genetics and evolutionary theory. He made the first significant synthesis of Charles Darwin's theory of evolution with Gregor Mendel's theory of genetics in his book Genetics and the Origin of Species (1937).
From 1918 his research gave experimental evidence that genes could vary far more than geneticists had previously believed. Thus, successful species tend to have a wide variety of genes that, while redundant in its present environment, do provide a species as a whole with genetic diversity. Such diversity enables the species to adapt effectively to changes in the surrounding environment - the basis for modern evolutionary theory.
Selasa, 14 Desember 2010
Died This Day: Louis Agassiz
(Jean) Louis (Rodolphe) Agassiz (May 28, 1807 - Dec. 14, 1873) was a Swiss-born U.S. naturalist, geologist, and teacher who made revolutionary contributions to the study of natural science with landmark work on glacier activity and extinct fishes. Agassiz began his work in Europe, having studied at the University of Munich and then as chair in natural history in Neuchatel in Switzerland. While there he published his landmark multi-volume description and classification of fossil fish.
In 1846 Agassiz came to the U.S. to lecture before Boston's Lowell Institute. Offered a professorship of Zoology and Geology at Harvard in 1848, he decided to stay, becoming a citizen in 1861. His innovative teaching methods altered the character of natural science education in the U.S. Link
More info HERE
In 1846 Agassiz came to the U.S. to lecture before Boston's Lowell Institute. Offered a professorship of Zoology and Geology at Harvard in 1848, he decided to stay, becoming a citizen in 1861. His innovative teaching methods altered the character of natural science education in the U.S. Link
More info HERE
Minggu, 12 Desember 2010
Born This Day: Sarah Douglas
Sarah gets a tip of the hat for playing Lady Charlotte Cunningham is the mostly forgotten Hammer Films adaptation of the Edgar Rice Burroughs novel of the same name.
Douglas is probably best known for playing the Phantom Zone Villianess Ursa in the 1978 Superman movie.
Douglas is probably best known for playing the Phantom Zone Villianess Ursa in the 1978 Superman movie.
Sabtu, 11 Desember 2010
Premiered This Day: Journey to the Beginning of Time
On this day in 1955 the Czech film, Cesta do praveku, by Karl Zeman debuted in East Germany.
It was laters redubbed and shown with additional footage as Journey to the Beginning of Time in the USA.
Selasa, 07 Desember 2010
Born This Day: Louis Dollo
From Today In Science History
Louis Antoine Marie Joseph Dollo (Dec. 7, 1857 – April 19, 1931) was a French vertebrate paleontologist who stated Dollo's Law of Irreversibility whereby in evolution an organism never returns exactly to its former state such that complex structures, once lost, are not regained in their original form. (While generally true, some exceptions are known.)
He began as an assistant (1882), became keeper of mammals (1891) at the Royal Museum of Natural History in Brussels where he stayed most of his life. He was a specialist in fossil fishes, reptiles, birds, and their palaeoecology. He supervised the excavation of the famous, multiple Iguanodons found in 1878 by miners deep underground, at Bernissart, Belgium. image
Louis Antoine Marie Joseph Dollo (Dec. 7, 1857 – April 19, 1931) was a French vertebrate paleontologist who stated Dollo's Law of Irreversibility whereby in evolution an organism never returns exactly to its former state such that complex structures, once lost, are not regained in their original form. (While generally true, some exceptions are known.)
He began as an assistant (1882), became keeper of mammals (1891) at the Royal Museum of Natural History in Brussels where he stayed most of his life. He was a specialist in fossil fishes, reptiles, birds, and their palaeoecology. He supervised the excavation of the famous, multiple Iguanodons found in 1878 by miners deep underground, at Bernissart, Belgium. image
Senin, 06 Desember 2010
Koreaceratops
The first ceratopsian dinosaur from South Korea. 2010. Y.-N. Lee, et al. Naturwissenschaften, published online 17 November.
Abstract [edit]: Koreaceratops hwaseongensis gen. et sp. nov. is a new basal neoceratopsian was discovered in the Tando beds (Albian) of Tando Basin in South Korea. It represents the first ceratopsian dinosaur in the Korean peninsula. Autapomorphies of Koreaceratops include very tall neural spines over five times higher than the associated centra in the distal caudals, and a unique astragalus divided into two fossae by a prominent craniocaudal ridge on the proximal surface.
A phylogenetic analysis indicates that Koreaceratops is positioned between Archaeoceratops and all more derived neoceratopsians, and the elongation of caudal neural spines was an important derived character in non-ceratopsid neoceratopsians. The very tall caudal neural spines in Koreaceratops, Montanoceratops, Udanoceratops, Protoceratops, and Bagaceratops appear to be homoplasious, suggesting an independent adaptation, possibly for swimming. Skeletal evidence suggests that obligate quadrupedalism occurred gradually in neoceratopsians progressing from bipedal through facultative quadrupedalism, to complete quadrupedalism in Coronosauria.
Abstract [edit]: Koreaceratops hwaseongensis gen. et sp. nov. is a new basal neoceratopsian was discovered in the Tando beds (Albian) of Tando Basin in South Korea. It represents the first ceratopsian dinosaur in the Korean peninsula. Autapomorphies of Koreaceratops include very tall neural spines over five times higher than the associated centra in the distal caudals, and a unique astragalus divided into two fossae by a prominent craniocaudal ridge on the proximal surface.
A phylogenetic analysis indicates that Koreaceratops is positioned between Archaeoceratops and all more derived neoceratopsians, and the elongation of caudal neural spines was an important derived character in non-ceratopsid neoceratopsians. The very tall caudal neural spines in Koreaceratops, Montanoceratops, Udanoceratops, Protoceratops, and Bagaceratops appear to be homoplasious, suggesting an independent adaptation, possibly for swimming. Skeletal evidence suggests that obligate quadrupedalism occurred gradually in neoceratopsians progressing from bipedal through facultative quadrupedalism, to complete quadrupedalism in Coronosauria.
Sabtu, 04 Desember 2010
Died This Day: Thomas Hunt Morgan
From Today In Science History:
Thomas Hunt Morgan (Sept. 25, 1866 – Dec. 4, 1945) was an American zoologist and geneticist, famous for his experimental research with the fruit fly by which he established the chromosome theory of heredity. He discovered that a number of genetic variations were inherited together and that this was because their controlling genes occurred on the same chromosome. In 1908, Morgan began breeding experiments with the fruit fly Drosophila melanogaster.
His study of the characteristics inherited by mutants ultimately enabled him to determine the precise behaviour and exact localization of genes. Morgan and his colleagues produced the first chromosome maps in 1911. Though this work was not widely accepted initially, Morgan was awarded a Nobel Prize for physiology or medicine in 1933. image
Thomas Hunt Morgan (Sept. 25, 1866 – Dec. 4, 1945) was an American zoologist and geneticist, famous for his experimental research with the fruit fly by which he established the chromosome theory of heredity. He discovered that a number of genetic variations were inherited together and that this was because their controlling genes occurred on the same chromosome. In 1908, Morgan began breeding experiments with the fruit fly Drosophila melanogaster.
His study of the characteristics inherited by mutants ultimately enabled him to determine the precise behaviour and exact localization of genes. Morgan and his colleagues produced the first chromosome maps in 1911. Though this work was not widely accepted initially, Morgan was awarded a Nobel Prize for physiology or medicine in 1933. image
Jumat, 03 Desember 2010
Kosmoceratops: Strange Science Fantasy?
This may be the quickest turn around time for a new dino appearing in an entertainment medium...
High Temperatures Catalyzed Primordial Life
Impact of temperature on the time required for the establishment of primordial biochemistry, and for the evolution of enzymes. 2010.R. B. Stockbridge, et al. PNAS, published online before print December 1.
Disney Explains evolution. A Classic!Enzymes, proteins that jump-start chemical reactions, are essential to life within cells of the human body and throughout nature. To appreciate how powerful modern enzymes are, and the process of how they evolved, researchers measured the speed of chemical reactions. They estimated that some reactions take more than 2 billion years without an enzyme. In the process of measuring slow reaction rates, "it gradually dawned on us that the slowest reactions are also the most temperature-dependent," Wolfenden said.
In general, the amount of influence temperature has on reaction speeds varies drastically, the group found. In one slow reaction, for instance, raising the temperature from 25 to 100 degrees Celsius increases the reaction rate 10 million fold.
High temperatures were probably a crucial influence on reaction rates when life began forming in hot springs and submarine vents. Later, the cooling of the earth provided selective pressure for primitive enzymes to evolve and become more sophisticated. link.
Disney Explains evolution. A Classic!
In general, the amount of influence temperature has on reaction speeds varies drastically, the group found. In one slow reaction, for instance, raising the temperature from 25 to 100 degrees Celsius increases the reaction rate 10 million fold.
High temperatures were probably a crucial influence on reaction rates when life began forming in hot springs and submarine vents. Later, the cooling of the earth provided selective pressure for primitive enzymes to evolve and become more sophisticated. link.
Kamis, 02 Desember 2010
Born This Day: Capt. Englehorn
Frank Reicher (Dec. 2, 1875 – Jan. 19, 1965) was born in Munich,Germany and had a long career in Hollywood. He appeared in over 200 films, often playing small roles in minor films, and he directed over three dozen silent movies.
He is best know for playing Capt. Englehorn in King King (1933), and it’s quickie sequel Son of Kong from later that same year.
Rabu, 01 Desember 2010
Rainforest Collapse Triggered Carboniferous Reptile Evolution
Rainforest collapse triggered Carboniferous tetrapod diversification in Euramerica. 2010. S. Sahney, et al. Geology 38: 1079-1082
Mike Benton of the University of Bristol added: "This is a classic ecological response to habitat fragmentation. You see the same process happening today whenever a group of animals becomes isolated from its parent population. It's been studied on traffic islands between major road systems or, as Charles Darwin famously observed in the Galapagos, on oceanic islands."
To reach their conclusions, the scientists studied the fossil record of reptiles before and after rainforest collapse. They showed that reptiles became more diverse and even changed their diet as they struggled to adapt to rapidly changing climate and environment. link
Global warming devastated tropical rainforests 300 million years ago. Now scientists report the unexpected discovery that this event triggered an evolutionary burst among reptiles -- and inadvertently paved the way for the rise of dinosaurs, 100 million years later.This event happened during the Carboniferous Period. At that time, Europe and North America lay on the equator and were covered by steamy tropical rainforests. But when the Earth's climate became hotter and drier, rainforests collapsed and fragmented into small 'islands' of forest. This isolated populations of reptiles and each community evolved in a separate direction, leading to an increase in diversity."
Mike Benton of the University of Bristol added: "This is a classic ecological response to habitat fragmentation. You see the same process happening today whenever a group of animals becomes isolated from its parent population. It's been studied on traffic islands between major road systems or, as Charles Darwin famously observed in the Galapagos, on oceanic islands."
To reach their conclusions, the scientists studied the fossil record of reptiles before and after rainforest collapse. They showed that reptiles became more diverse and even changed their diet as they struggled to adapt to rapidly changing climate and environment. link
Died This Day: Godfrey Harold Hardy
Hardy (Feb. 7, 1877 – Dec. 1, 1947) was an English mathematician known for his work in number theory and mathematical analysis. Although Hardy considered himself a pure mathematician, he nevertheless worked in applied mathematics when he formulated a law that describes how proportions of dominant and recessive genetic traits will propagate in a large population (1908). Hardy considered it unimportant but it has proved of major importance in blood group distribution. As it was also independently discovered by Weinberg, it is known as the Hardy-Weinberg principle.
The Hardy-Weinberg equation
The Hardy-Weinberg equation
Died This Day: J.B.S. Haldane
Haldane (Nov. 5, 1892 - Dec. 1, 1964) is best remembered along with E. B. Ford and R. A. Fisher one of the three major figures to develop the mathematical theory of population genetics. His greatest contribution was in a series of ten papers on "A Mathematical Theory of Natural and Artificial Selection" which was the major series of papers on the mathematical theory of natural selection. It treated many major cases for the first time, showing the direction and rates of changes of gene frequencies. It also pioneered in investigating the interaction of natural selection with mutation and with migration.
Haldane's book, The Causes of Evolution (1932), summarized these results, especially in its extensive appendix. This body of work was a component of what came to be known as the "modern evolutionary synthesis", re-establishing natural selection as the premier mechanism of evolution by explaining it in terms of the mathematical consequences of Mendelian genetics. From Wikipedia. More info here.
Haldane's book, The Causes of Evolution (1932), summarized these results, especially in its extensive appendix. This body of work was a component of what came to be known as the "modern evolutionary synthesis", re-establishing natural selection as the premier mechanism of evolution by explaining it in terms of the mathematical consequences of Mendelian genetics. From Wikipedia. More info here.
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