Wanting to learn some basic facts about dinosaurs,
The Asahi Shimbun GLOBE and, through Twitter, some of its readers posed
questions to Makoto Manabe, a senior scientist at the National Museum of
Nature and Science.
GLOBE: Could you please provide us with a definition for a dinosaur?
Manabe: Roughly corresponding to the arms and legs of a human, appendages protrude from the sides of a reptile’s elongated body. Lifting their trunks off the ground in a push-up-like manner, they use these four splayed legs to wiggle themselves forward. During the course of evolution, however, some reptilians developed front and back limbs held erect beneath their bodies, allowing them to walk in an upright manner. These were dinosaurs. They were able to run faster than other reptiles and also range farther while expending the same amount of energy; it is believed they flourished as a result.
Dinosaurs are also classified according to other detailed characteristics such as having a hole in the femoral joint and a sacrum (large, triangular bone at the base of the spine) composed of not less than three fused vertebrae.
The name “dinosaur” is attributed to British paleontologist Richard Owen who used it as a general term to define megalosaurus, iguanodon and hylaeosaurus back in 1842. Plesiosaur (aquatic animals) and pterosaur (winged lizards), which existed at the same time as dinosaurs, are not classified as such.
There are many ways of defining dinosaurs; one is “the most recent common ancestors of Owen’s three species and all their descendants.” Whichever definition is used, however, all share the commonality of including the birds of today as “descendants.”
@yuminyuming: Is it possible to bring dinosaurs back to life?
A: In the novel "Jurassic Park," dinosaurs were resurrected by extracting DNA from dinosaur blood found in a mosquito preserved in prehistoric amber. While theoretically possible, the probability of the complete genome being preserved is extremely low, making it very difficult to realize such a feat.
@yukialice: To what extent is there accurate information about dinosaurs, such as the presence or absence of hair, color, etc.?
A: Fossilized feathers and scales have been discovered, though ground water sediments have permeated them, leading to discoloration. “Not knowing the color” is conventional wisdom as it pertains to dinosaurs. In 2010, a pigment-producing organ was found on the surface of a feather belonging to a feathered dinosaur fossil. By measuring the shape and density of the organ, the color came to be known. It’s also been proven that a dinosaur with a red patch at the top of its head and one with a striped tail existed.
@snkzombi333: What did dinosaurs eat?
A: It would be great if the stomach content of dinosaurs was also fossilized; unfortunately, however, such occurrences are extremely rare. Based on tooth marks left on fossilized dinosaur bones, we have come to realize that in all likelihood tyrannosaurus preyed on triceratops and other species. Examining fossilized feces is also very important in this regard, but identifying the animal which they came from is difficult. Incidentally, bones belonging to a baby dinosaur were discovered in the fossilized stomach of a mammalia class animal, meaning mammals at the time weren’t just prey for the dinosaurs.
GLOBE: Which was the most powerful dinosaur?
A: I am often asked which was stronger, the tyrannosaurus or the even larger carnivorous spinosaurus. Without actually pitting them against each other, however, we’ll never know. And with the tyrannosaurus being native to North America and the spinosaurus inhabiting Africa, they probably never met. Though carnivorous dinosaurs were at the top of the food chain, it probably wasn’t easy for them to bring down herbivorous sauropods in the 20- to 30-meter length class.
Q: Did dinosaurs get sick or become ill?
A: Yes, in addition to finding broken bones, traces of mended bone fractures and marks on bones indicating injury, there have been a great number of deformities discovered that are believed to have been caused by infectious disease. The tip of a toe on one tyrannosaurus was found to be deformed, and the cause is believed to have been gout.
Q: What does it take to become a dinosaur researcher?
A: The normal route is to study subjects like earth sciences, biology, geology, paleontology and zoology at university and then go on to conduct research on dinosaurs and other birds and reptiles from the Mesozoic Era at graduate school and obtain a doctorate. Recently, however, other forms of research, including engineering-centric work such as computer simulations and embryological research on birds, are being applied to the study of dinosaurs, so the paths leading to dinosaur research are diversifying. When asked this question by junior and senior high school students, I tell them it is important to have an interest in English because science researchers must collect information from English language sources and also write papers in English.
Q: Why are people so attracted to dinosaurs?
A: I think both adults and children are intrigued by the fact that there existed at one time creatures we can scarcely imagine by looking at the animals of today. People often say dinosaurs are “cool” when expressing their fascination with attributes such as their size, distinctive appearance and strength. Dinosaurs are also sometimes thought of as being cute as evidenced by some toys and stuffed animals made in their likeness. Some adults have also said they feel comforted by the slow, leisurely walk of gigantic herbivorous dinosaurs.
Q: What would the world be like if dinosaurs had not become extinct?
A: Some dinosaurs transformed into birds and are continuing to evolve; so not all of them became extinct. However, it is a fact that well-known dinosaurs such as the tyrannosaurus and triceratops were wiped out 66 million years ago. Prior to their extinction, sociality was developing among dinosaurs. If the majority of dinosaurs had not met with extinction, our time as mammals may not have come about.
THE GRIEF OF MASS EXTINCTION
Regardless of national boundaries, throughout the ages dinosaurs have never ceased to fascinate people. Wanting to find out why, I started collecting information on these “terrible lizards” from the past for this feature.
The primary reason we are attracted to dinosaurs is their size and strength. Some herbivorous dinosaurs such as seismosaurus and Argentinosaurus grew to lengths in excess of 30 meters.
In the latter part of the 19th century during America’s Wild West, the “steel king,” Andrew Carnegie, an avid supporter of fossil hunters, constructed a natural history museum in Pittsburgh. Among the collection of more than 19 million pieces is a near-complete skeleton of D. carnegii, a species of diplodocus named after Carnegie, which for a long time ranked as the world’s longest dinosaur (26 meters in length). During this period, the discovery of gigantic fossilized dinosaur remains proceeded hand in hand with territorial expansion. It can be said that dinosaurs served as a symbol of a country’s size and strength.
If size and strength are positive dinosaur associations, there are negative ones as well.
Remote mammalian ancestors of humankind lived in fear of dinosaurs. I have heard a tentative theory suggesting that because the memory of such scary times is engraved in the back of our brains, humans continue to have an innate fear of reptiles even to this day. According to this hypothesis, then, when we look at pictures of dinosaurs, this ancient memory of terror is suddenly revived. That is why people look at images of dinosaurs when they “want to see something scary.”
There is another negative association as well. The strongest creatures to rule the Earth for 160 million years across the Triassic, Jurassic and Cretaceous periods, it is well-known that most dinosaurs suddenly vanished about 66 million years ago. Along with feeling grief for this loss, their sudden demise forces us to think about the future in store for mankind as well.
In 1980, American scientist Luis Alvarez, winner of the Nobel Prize in Physics, and his son Walter Alvarez, published a paper suggesting a gigantic meteorite crashing to Earth caused the extinction of the dinosaurs. In 2010, an international panel of researchers concluded this hypothesis to be correct.
In prehistoric times, an asteroid measuring 10 to 15 kilometers in diameter and traveling at 20 kilometers per second slammed into the Gulf of Mexico, releasing an amount of energy equivalent to 1 billion times the amount produced by the atomic bomb dropped on Hiroshima. The impact created a huge tsunami 300 meters in height that swallowed up the dinosaurs. Those that survived the initial tsunami died off one by one due to sudden changes in the climate, such as cooling caused by soot resulting from tropical forests burning out of control, and acid rain resulting from chemical substances generated by the impact.
It is said the probability of an asteroid this size impacting the Earth is one in tens of millions to hundreds of millions of years occurrence. Over a long, long history, being around in a period that is struck by just one such asteroid is indeed unfortunate.
“For the Japanese, who are attracted to stories like "The Tale of the Heike," which asserts that even the most prosperous inevitably decay, the tragedy of the last days of the overwhelmingly powerful dinosaurs probably touches their heartstrings,” said Keio University professor Takayuki Tatsumi, who is familiar with the culture of dinosaurs in both Japan and the United States.
Only about 200,000 years have passed since modern humans first appeared on the planet. Yet we are already negatively impacting our environment by creating problems such as global warming, deforestation and water pollution. Currently it is estimated that 100 species of organisms are becoming extinct each day and some people are calling these times the “sixth period of mass extinction,” comparable to the five major extinction events that have occurred since life began on Earth.
Takafumi Matsui, director of the Planetary Exploration Research Center of Chiba Institute of Technology, said, “Rather than worrying about whether or not a celestial body will strike the Earth, we should think carefully about the message dinosaurs left us: namely, why they were able to thrive over a period lasting 160 million years.”
GLOBE: Could you please provide us with a definition for a dinosaur?
Manabe: Roughly corresponding to the arms and legs of a human, appendages protrude from the sides of a reptile’s elongated body. Lifting their trunks off the ground in a push-up-like manner, they use these four splayed legs to wiggle themselves forward. During the course of evolution, however, some reptilians developed front and back limbs held erect beneath their bodies, allowing them to walk in an upright manner. These were dinosaurs. They were able to run faster than other reptiles and also range farther while expending the same amount of energy; it is believed they flourished as a result.
Dinosaurs are also classified according to other detailed characteristics such as having a hole in the femoral joint and a sacrum (large, triangular bone at the base of the spine) composed of not less than three fused vertebrae.
The name “dinosaur” is attributed to British paleontologist Richard Owen who used it as a general term to define megalosaurus, iguanodon and hylaeosaurus back in 1842. Plesiosaur (aquatic animals) and pterosaur (winged lizards), which existed at the same time as dinosaurs, are not classified as such.
There are many ways of defining dinosaurs; one is “the most recent common ancestors of Owen’s three species and all their descendants.” Whichever definition is used, however, all share the commonality of including the birds of today as “descendants.”
@yuminyuming: Is it possible to bring dinosaurs back to life?
A: In the novel "Jurassic Park," dinosaurs were resurrected by extracting DNA from dinosaur blood found in a mosquito preserved in prehistoric amber. While theoretically possible, the probability of the complete genome being preserved is extremely low, making it very difficult to realize such a feat.
@yukialice: To what extent is there accurate information about dinosaurs, such as the presence or absence of hair, color, etc.?
A: Fossilized feathers and scales have been discovered, though ground water sediments have permeated them, leading to discoloration. “Not knowing the color” is conventional wisdom as it pertains to dinosaurs. In 2010, a pigment-producing organ was found on the surface of a feather belonging to a feathered dinosaur fossil. By measuring the shape and density of the organ, the color came to be known. It’s also been proven that a dinosaur with a red patch at the top of its head and one with a striped tail existed.
@snkzombi333: What did dinosaurs eat?
A: It would be great if the stomach content of dinosaurs was also fossilized; unfortunately, however, such occurrences are extremely rare. Based on tooth marks left on fossilized dinosaur bones, we have come to realize that in all likelihood tyrannosaurus preyed on triceratops and other species. Examining fossilized feces is also very important in this regard, but identifying the animal which they came from is difficult. Incidentally, bones belonging to a baby dinosaur were discovered in the fossilized stomach of a mammalia class animal, meaning mammals at the time weren’t just prey for the dinosaurs.
GLOBE: Which was the most powerful dinosaur?
A: I am often asked which was stronger, the tyrannosaurus or the even larger carnivorous spinosaurus. Without actually pitting them against each other, however, we’ll never know. And with the tyrannosaurus being native to North America and the spinosaurus inhabiting Africa, they probably never met. Though carnivorous dinosaurs were at the top of the food chain, it probably wasn’t easy for them to bring down herbivorous sauropods in the 20- to 30-meter length class.
Q: Did dinosaurs get sick or become ill?
A: Yes, in addition to finding broken bones, traces of mended bone fractures and marks on bones indicating injury, there have been a great number of deformities discovered that are believed to have been caused by infectious disease. The tip of a toe on one tyrannosaurus was found to be deformed, and the cause is believed to have been gout.
Q: What does it take to become a dinosaur researcher?
A: The normal route is to study subjects like earth sciences, biology, geology, paleontology and zoology at university and then go on to conduct research on dinosaurs and other birds and reptiles from the Mesozoic Era at graduate school and obtain a doctorate. Recently, however, other forms of research, including engineering-centric work such as computer simulations and embryological research on birds, are being applied to the study of dinosaurs, so the paths leading to dinosaur research are diversifying. When asked this question by junior and senior high school students, I tell them it is important to have an interest in English because science researchers must collect information from English language sources and also write papers in English.
Q: Why are people so attracted to dinosaurs?
A: I think both adults and children are intrigued by the fact that there existed at one time creatures we can scarcely imagine by looking at the animals of today. People often say dinosaurs are “cool” when expressing their fascination with attributes such as their size, distinctive appearance and strength. Dinosaurs are also sometimes thought of as being cute as evidenced by some toys and stuffed animals made in their likeness. Some adults have also said they feel comforted by the slow, leisurely walk of gigantic herbivorous dinosaurs.
Q: What would the world be like if dinosaurs had not become extinct?
A: Some dinosaurs transformed into birds and are continuing to evolve; so not all of them became extinct. However, it is a fact that well-known dinosaurs such as the tyrannosaurus and triceratops were wiped out 66 million years ago. Prior to their extinction, sociality was developing among dinosaurs. If the majority of dinosaurs had not met with extinction, our time as mammals may not have come about.
THE GRIEF OF MASS EXTINCTION
Regardless of national boundaries, throughout the ages dinosaurs have never ceased to fascinate people. Wanting to find out why, I started collecting information on these “terrible lizards” from the past for this feature.
The primary reason we are attracted to dinosaurs is their size and strength. Some herbivorous dinosaurs such as seismosaurus and Argentinosaurus grew to lengths in excess of 30 meters.
In the latter part of the 19th century during America’s Wild West, the “steel king,” Andrew Carnegie, an avid supporter of fossil hunters, constructed a natural history museum in Pittsburgh. Among the collection of more than 19 million pieces is a near-complete skeleton of D. carnegii, a species of diplodocus named after Carnegie, which for a long time ranked as the world’s longest dinosaur (26 meters in length). During this period, the discovery of gigantic fossilized dinosaur remains proceeded hand in hand with territorial expansion. It can be said that dinosaurs served as a symbol of a country’s size and strength.
If size and strength are positive dinosaur associations, there are negative ones as well.
Remote mammalian ancestors of humankind lived in fear of dinosaurs. I have heard a tentative theory suggesting that because the memory of such scary times is engraved in the back of our brains, humans continue to have an innate fear of reptiles even to this day. According to this hypothesis, then, when we look at pictures of dinosaurs, this ancient memory of terror is suddenly revived. That is why people look at images of dinosaurs when they “want to see something scary.”
There is another negative association as well. The strongest creatures to rule the Earth for 160 million years across the Triassic, Jurassic and Cretaceous periods, it is well-known that most dinosaurs suddenly vanished about 66 million years ago. Along with feeling grief for this loss, their sudden demise forces us to think about the future in store for mankind as well.
In 1980, American scientist Luis Alvarez, winner of the Nobel Prize in Physics, and his son Walter Alvarez, published a paper suggesting a gigantic meteorite crashing to Earth caused the extinction of the dinosaurs. In 2010, an international panel of researchers concluded this hypothesis to be correct.
In prehistoric times, an asteroid measuring 10 to 15 kilometers in diameter and traveling at 20 kilometers per second slammed into the Gulf of Mexico, releasing an amount of energy equivalent to 1 billion times the amount produced by the atomic bomb dropped on Hiroshima. The impact created a huge tsunami 300 meters in height that swallowed up the dinosaurs. Those that survived the initial tsunami died off one by one due to sudden changes in the climate, such as cooling caused by soot resulting from tropical forests burning out of control, and acid rain resulting from chemical substances generated by the impact.
It is said the probability of an asteroid this size impacting the Earth is one in tens of millions to hundreds of millions of years occurrence. Over a long, long history, being around in a period that is struck by just one such asteroid is indeed unfortunate.
“For the Japanese, who are attracted to stories like "The Tale of the Heike," which asserts that even the most prosperous inevitably decay, the tragedy of the last days of the overwhelmingly powerful dinosaurs probably touches their heartstrings,” said Keio University professor Takayuki Tatsumi, who is familiar with the culture of dinosaurs in both Japan and the United States.
Only about 200,000 years have passed since modern humans first appeared on the planet. Yet we are already negatively impacting our environment by creating problems such as global warming, deforestation and water pollution. Currently it is estimated that 100 species of organisms are becoming extinct each day and some people are calling these times the “sixth period of mass extinction,” comparable to the five major extinction events that have occurred since life began on Earth.
Takafumi Matsui, director of the Planetary Exploration Research Center of Chiba Institute of Technology, said, “Rather than worrying about whether or not a celestial body will strike the Earth, we should think carefully about the message dinosaurs left us: namely, why they were able to thrive over a period lasting 160 million years.”
No comments:
Post a Comment