Origin of The Komodo Dragon

Dragons may come from the land Down Under.
Scientists now find that the world’s largest living lizard species, the Komodo dragon, most likely evolved in Australia and dispersed westward to its current home in Indonesia.
In the past, researchers had suggested the Komodo dragon (Varanus komodoensis) developed from a smaller ancestor isolated on the Indonesian islands, evolving its large size as a response to lack of competition from other predators or as a specialist hunter of pygmy elephants known as Stegodon.

However, over the past three years, an international team of scientists unearthed numerous fossils from eastern Australia dated from 300,000 years ago to roughly 4 million years ago that they now know belong to the Komodo dragon.
"When we compared these fossils to the bones of present-day Komodo dragons, they were identical," said researcher Scott Hocknull, a vertebrate paleontologist at the Queensland Museum in Australia.
For the last 4 million years, Australia has been home to the world's largest lizards, including the 16-foot-long giant (5 meters) called Megalania, once the world's largest terrestrial lizard but which died out some 40,000 years ago.
"Now we can say Australia was also the birthplace of the three-meter (10 foot) Komodo dragon," Hocknull said.
The researchers said the ancestor of the Komodo dragon most likely evolved in Australia and spread westward, reaching the Indonesian island of Flores by 900,000 years ago. Comparisons between fossils and living Komodo dragons on Flores show that the lizard's body size has remained relatively stable since then.
Further support for this notion of dispersal from Australia comes from the island of Timor, located between Australia and Flores. Three fossil specimens from Timor represent a new, as yet unnamed species of giant monitor lizard, which was larger than the Komodo dragon, although smaller than Megalania. More specimens of this new giant lizard are needed before the species can be formally described.
"There are a lot of things we just simply don't know about this part of the world — Indonesia to Australia," Hocknull told LiveScience. "In recent years this region has thrown up remarkable discoveries — a new species of hominid, the 'Lost World' in New Guinea boasting dozens of new species having never met humans, and now an island chain of giant lizards, including the largest of them all, Megalania from Australia. However, they all went extinct, except the Komodo dragon. The big question now is why? The south-east Asian to Australian region is a hot-spot of new and exciting discoveries."
All these huge lizards were once common in Australasia for more than 3.8 million years, having evolved alongside large mammalian carnivores, such as Thylacoleo, the so-called 'marsupial lion.' The Komodo dragon is the last of these giants, but within the last 2,000 years, their populations have diminished severely, most likely due to humans, and they are now vulnerable to extinction, living now on just a few isolated islands in eastern Indonesia, between Java and Australia.
"Understanding the past history of a species is absolutely fundamental to determining its potential trajectory in the future, its responses to climate change, habitat change and extinction events," Hocknull said. "The Komodo dragon's fossil record shows that it is a resilient species — resilient to major climatic changes throughout its past, surviving extinction events which wiped out contemporary megafauna species."
One question that now pops up is why the Komodo dragon went extinct on Australia while surviving on a few isolated Indonesian isles. Hocknull noted that climate was an unlikely suspect, as "climate impacts species on islands just as much as a big continent like Australia. In Australia there is plenty of habitat which could be conducive to Komodo dragons. If you released them in Australia today they would probably do quite well."
Were humans involved? "We have no evidence for this because the youngest Komodo fossils in Australia are around 300,000 years old, well before humans arrived. So we don't know whether the Komodo dragons in Australia died out before humans arrived or after. So the jury will remain out on this question until a better fossil record is found."
Hocknull noted these islands of lizards are each, in a sense, individual experiments in evolution that shed light not only on the past of these lizards, but potentially also on the future of the world.
"It's a perfect place to see how life adapts and evolves in response to major environmental impacts, like sea level change, climatic changes, catastrophes — tsunamis and volcanic eruptions — plus each island has received modern humans at one time or another," he explained. "What were their impacts and how did species cope? This will be our Rosetta Stone when understanding how species will respond to future climate change."

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What Killed The Dinosaurs?

THE GREAT MYSTERY Surely ever since the first fossils of obviously extinct animals were found, humankind has wondered: "Why did they die?" A poignant question, for it has relevance to us — if extinct animals were wiped out by some catastrophe, couldn't that just as easily happen to us? Could we be found as fossils someday, and would no one know why we died?

History: Until recently, people simply knew that dinosaurs went extinct — their fossils were found throughout the Mesozoic era, but were not located in the rock layers (strata) of the Cenozoic era. So, we knew that dinosaurs went extinct some 64-66 million years ago, but that was all. Many wild ideas about how the dinosaurs were rendered extinct were presented over the years.
1980: Few satisfactory answers to the mystery behind the extinction of dinosaurs were offered until 1980, when a group of scientists at the University of California at Berkeley — Luis and Walter Alvarez, Frank Asaro, and Helen Michel — proposed a stunning and convincing mechanism for the "K-T extinction" (meaning the extinction of dinosaurs at the boundary between the Cretaceous period (K) and the Tertiary period (T)). This hypothesis is discussed later. Since the Alvarez hypothesis was first proposed, the search for the "perpetrator" of the K-T extinction has been a thriving area of scientific research. It incorporates scientists from many different fields including astrophysics, astronomy, geology, paleontology, ecology, geochemistry, and so on. The mystery has drawn extensive media coverage over the last 15 years, as you may know; some paleontologists have since lost interest in the issue, preferring to study how the dinosaurs and their contemporaries lived rather than why they died.
Mass Extinctions: But before we dive into the complex issue of the K-T extinction, we need essential background information to understand the basics of the controversy. The "great dying," as it is sometimes called, is an example of a mass extinction: an episode in evolutionary history where more than 50% of all known species living at that time went extinct in a short period of time (less than 2 million years or so).
Other Mass Extinctions? We know of several mass extinctions in the history of life; the great dying is not nearly the largest! The largest would be the "Permo-Triassic" extinction, between the Permian and Triassic periods, of the Paleozoic and Mesozoic eras. In this obviously catastrophic event, life on Earth nearly was wiped out — an estimated 90% of all species living at that time were extinguished. We are fairly sure that the extinction was due to many changing global conditions at that time, but even that is not solved yet. The issue has not received much press because the dinosaurs were not involved, but another familiar group, the trilobites, were wiped out among others. Who Died? How does the K-T extinction compare to this debacle? Well, about 60% of all species that are present below the K-T boundary are not present above the line that divides the "Age of Dinosaurs" and the "Age of Mammals." In fact, dinosaurs were not among the most numerous of the casualties — the worst hit organisms were those in the oceans. Large groups of organisms, including some members of Foraminifera, Echinodermata, Mollusca, and the marine Diapsida all were devastated by the K-T event. On land, the Dinosauria of course went extinct, along with the Pterosauria. Mammals and most non- dinosaurian reptiles seemed to be relatively unaffected. The terrestrial plants suffered to a large extent, except for the ferns, which show an apparently dramatic increase in diversity at the K-T boundary, a phenomenon known as the fern spike.
Complications
Now we're heading into the tough stuff; the reasons why we have no conclusive answer to the mystery of the K-T event. Several complications that make work hard for the scientist/detectives trying to crack this case:

1. The Fossil Record: It's not perfect, as you may know; that's why paleontologists keep finding new fossils: so much is hidden in the rocks! Most data on the K-T event comes from North America, which is one of the few areas known that has a somewhat continuous fossil record (remember, fossils are only formed under certain rare conditions, and are only found in sedimentary rocks). The infamous Hell Creek locality in Montana is one such continuous site enclosing the K-T boundary. UCMP researchers have led and continue to lead expeditions to Hell Creek, gathering fossils from the rich fossil beds. The secret to the K-T event may lie within our collections; who knows! Anyway, we don't know much about what was occurring in the rest of the world at the time of the K-T event. The marine fossil record gives us great hints about what was occurring within the sea, but how applicable is that to what went on in the terrestrial realm?
2. The Nature of Extinction: Extinction is not a simple event; it is not simply the death of all representatives of a group. It is the cessation of the origination of new species that renders a group extinct; if species are constantly dying off and no new ones originate through the process of evolution, then that group will go extinct over time no matter what happens. New dinosaur species ceased to originate around the K-T boundary; the question is, were they killed off (implying causation, especially a catastrophe), or were they not evolving and simply fading away (perhaps implying gradual environmental change)?
3. Time Resolution: Determining the age of rocks or fossils that are millions of years old is not easy; carbon dating only has a reasonable resolution when used with organic material that is less than about 50,000 years old, so it is useless with the 65 million year old K-T material. Other methods of age determination are often less accurate or less useful in certain situations. So we don't know exactly when the dinosaurs went extinct, and matching events precisely to give a picture of what was happening at a specific moment in the Mesozoic is not easy. Thus, the ultimate question of a gradual decline of dinosaurs vs. a sudden cataclysm is almost intractable without a wealth of good data.
4. Reconstruction: To truly understand the situation of the dinosaurs around the K-T boundary, we need to understand the paleoecology of that time on Earth. Paleoecology is an extension of the discipline of ecology, attempting to understand the interactions of organisms with their environment, using geological (the rocks tell you what the soil was like, and thus tell a lot about the abiotic (non-living) environment) and paleontological (what plants and animals are found as fossils tell you a lot about the biotic (living) environment) evidence. With the problems of the fossil record and time resolution, it is difficult to understand the paleoecology of a region at a specific time in the past.
5. The Signor-Lipps Effect: Proposed by Phil Signor and UCMP's own Jere Lipps, this concept helps us to understand the limitations of the fossil record. The theory states that groups of organisms may seem to go extinct in the fossil record before they actually do; this is an artifact of the fickle nature of the fossil record rather than actual extinction. Thus, it is possible that some groups of organisms did not go extinct at the K-T boundary, and also possible that some organisms that seemed to have gone extinct earlier may have survived up to the boundary, and then gone extinct. This matter further complicates the important issue of the selectivity of the K-T extinction (discussed later).
6. Falsifiability: Sad but true: many hypotheses about dinosaur extinction sound quite convincing and might even be correct, but, as you know, are not really science if they cannot be proven or disproved. Even with the best hypothesis, such as the impact hypothesis, it is very difficult to prove or disprove whether the dinosaurs were rendered extinct by an event that occurred around the K-T boundary, or whether they were just weakened (or unaffected) by the event. This is not to say that all extinction hypotheses are not science; many are excellent examples of good science, but a linkage of direct causation is a problem. "Why" questions, such as "Why did the dinosaurs die out?" or "Why did dinosaurs evolve?" are among the most difficult questions in paleontology. Ultimately, a time machine would be required to see exactly what killed the dinosaurs.

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The Lost City of Atlantis

 The Lost City of Atlantis

If the writing of the ancient Greek philosopher Plato had not contained so much truth about the human condition, his name would have been forgotten centuries ago.
But one of his most famous stories—the cataclysmic destruction of the ancient civilization of Atlantis—is almost certainly false. So why is this story still repeated more than 2,300 years after Plato's death?
"It's a story that captures the imagination," says James Romm, a professor of classics at Bard College in Annandale, New York. "It's a great myth. It has a lot of elements that people love to fantasize about."
Plato told the story of Atlantis around 360 B.C. The founders of Atlantis, he said, were half god and half human. They created a utopian civilization and became a great naval power. Their home was made up of concentric islands separated by wide moats and linked by a canal that penetrated to the center. The lush islands contained gold, silver, and other precious metals and supported an abundance of rare, exotic wildlife. There was a great capital city on the central island.
There are many theories about where Atlantis was—in the Mediterranean, off the coast of Spain, even under what is now Antarctica. "Pick a spot on the map, and someone has said that Atlantis was there," says Charles Orser, curator of history at the New York State Museum in Albany. "Every place you can imagine."
Plato said Atlantis existed about 9,000 years before his own time, and that its story had been passed down by poets, priests, and others. But Plato's writings about Atlantis are the only known records of its existence.
Possibly Based on Real Events?
Few, if any, scientists think Atlantis actually existed. Ocean explorer Robert Ballard, the National Geographic explorer-in-residence who discovered the wreck of the Titanic in 1985, notes that "no Nobel laureates" have said that what Plato wrote about Atlantis is true.
Still, Ballard says, the legend of Atlantis is a "logical" one since cataclysmic floods and volcanic explosions have happened throughout history, including one event that had some similarities to the story of the destruction of Atlantis. About 3,600 years ago, a massive volcanic eruption devastated the island of Santorini in the Aegean Sea near Greece. At the time, a highly advanced society of Minoans lived on Santorini. The Minoan civilization disappeared suddenly at about the same time as the volcanic eruption.
But Ballard doesn't think Santorini was Atlantis, because the time of the eruption on that island doesn't coincide with when Plato said Atlantis was destroyed.
Romm believes Plato created the story of Atlantis to convey some of his philosophical theories. "He was dealing with a number of issues, themes that run throughout his work," he says. "His ideas about divine versus human nature, ideal societies, the gradual corruption of human society—these ideas are all found in many of his works. Atlantis was a different vehicle to get at some of his favorite themes."
The legend of Atlantis is a story about a moral, spiritual people who lived in a highly advanced, utopian civilization. But they became greedy, petty, and "morally bankrupt," and the gods "became angry because the people had lost their way and turned to immoral pursuits," Orser says.
As punishment, he says, the gods sent "one terrible night of fire and earthquakes" that caused Atlantis to sink into the sea.

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History of Pyramid

Built during a time when Egypt was one of the richest and most powerful civilizations in the world, the pyramids—especially the Great Pyramids of Giza—are some of the most magnificent man-made structures in history. Their massive scale reflects the unique role that the pharaoh, or king, played in ancient Egyptian society. Though pyramids were built from the beginning of the Old Kingdom to the close of the Ptolemaic period in the fourth century A.D., the peak of pyramid building began with the late third dynasty and continued until roughly the sixth (c. 2325 B.C.). More than 4,000 years later, the Egyptian pyramids still retain much of their majesty, providing a glimpse into the country’s rich and glorious past.

The Pharaoh in Egyptian Society

During the third and fourth dynasties of the Old Kingdom, Egypt enjoyed tremendous economic prosperity and stability. Kings held a unique position in Egyptian society. Somewhere in between human and divine, they were believed to have been chosen by the gods to serve as mediators between them and the people on earth. Because of this, it was in everyone’s interest to keep the king’s majesty intact even after his death, when he was believed to become Osiris, god of the dead. The new pharaoh, in turn, became Horus, the falcon-god who served as protector of the sun-god, Ra.

Did You Know?

The pyramid's smooth, angled sides symbolized the rays of the sun and were designed to help the king's soul ascend to heaven and join the gods, particularly the sun god Ra.

Ancient Egyptians believed that when the king died, part of his spirit (known as “ka”) remained with his body. To properly care for his spirit, the corpse was mummified, and everything the king would need in the afterlife was buried with him, including gold vessels, food, furniture and other offerings. The pyramids became the focus of a cult of the dead king that was supposed to continue well after his death. Their riches would provide not only for him, but also for the relatives, officials and priests who were buried near him.

The Early Pyramids

From the beginning of the Dynastic Era (2950 B.C.), royal tombs were carved into rock and covered with flat-roofed rectangular structures known as “mastabas,” which were precursors to the pyramids. The oldest known pyramid in Egypt was built around 2630 B.C. at Saqqara, for the third dynasty’s King Djoser. Known as the Step Pyramid, it began as a traditional mastaba but grew into something much more ambitious. As the story goes, the pyramid’s architect was Imhotep, a priest and healer who some 1,400 years later would be deified as the patron saint of scribes and physicians. Over the course of Djoser’s nearly 20-year reign, pyramid builders assembled six stepped layers of stone (as opposed to mud-brick, like most earlier tombs) that eventually reached a height of 204 feet (62 meters); it was the tallest building of its time. The Step Pyramid was surrounded by a complex of courtyards, temples and shrines, where Djoser would enjoy his afterlife.
After Djoser, the stepped pyramid became the norm for royal burials, although none of those planned by his dynastic successors were completed (probably due to their relatively short reigns). The earliest tomb constructed as a “true” (smooth-sided, not stepped) pyramid was the Red Pyramid at Dahshur, one of three burial structures built for the first king of the fourth dynasty, Sneferu (2613-2589 B.C.) It was named for the color of the limestone blocks used to construct the pyramid’s core.

The Great Pyramids of Giza

No pyramids are more celebrated than the Great Pyramids of Giza, located on a plateau on the west bank of the Nile River, on the outskirts of modern-day Cairo. The oldest and largest of the three pyramids at Giza, known as the Great Pyramid, is the only surviving structure out of the famed seven wonders of the ancient world. It was built for Khufu (Cheops, in Greek), Sneferu’s successor and the second of the eight kings of the fourth dynasty. Though Khufu reigned for 23 years (2589-2566 B.C.), relatively little is known of his reign beyond the grandeur of his pyramid. The sides of the pyramid’s base average 755.75 feet (230 meters), and its original height was 481.4 feet (147 meters), making it the largest pyramid in the world. Three small pyramids built for Khufu’s queens are lined up next to the Great Pyramid, and a tomb was found nearby containing the empty sarcophagus of his mother, Queen Hetepheres. Like other pyramids, Khufu’s is surrounded by rows of mastabas, where relatives or officials of the king were buried to accompany and support him in the afterlife.
The middle pyramid at Giza was built for Khufu’s son Khafre (2558-2532 B.C). A unique feature built inside Khafre’s pyramid complex was the Great Sphinx, a guardian statue carved in limestone with the head of a man and the body of a lion. It was the largest statue in the ancient world, measuring 240 feet long and 66 feet high. In the 18th dynasty (c. 1500 B.C.) the Great Sphinx would come to be worshiped itself, as the image of a local form of the god Horus. The southernmost pyramid at Giza was built for Khafre’s son Menkaure (2532-2503 B.C.). It is the shortest of the three pyramids (218 feet) and is a precursor of the smaller pyramids that would be constructed during the fifth and sixth dynasties.
Approximately 2.3 million blocks of stone (averaging about 2.5 tons each) had to be cut, transported and assembled to build Khufu’s Great Pyramid. The ancient Greek historian Herodotus wrote that it took 20 years to build and required the labor of 100,000 men, but later archaeological evidence suggests that the workforce might actually have been around 20,000. Though some popular versions of history held that the pyramids were built by slaves or foreigners forced into labor, skeletons excavated from the area show that the workers were probably native Egyptian agricultural laborers who worked on the pyramids during the time of year when the Nile River flooded much of the land nearby.

The End of the Pyramid Era

Pyramids continued to be built throughout the fifth and sixth dynasties, but the general quality and scale of their construction declined over this period, along with the power and wealth of the kings themselves. In the later Old Kingdom pyramids, beginning with that of King Unas (2375-2345 B.C), pyramid builders began to inscribe written accounts of events in the king’s reign on the walls of the burial chamber and the rest of the pyramid’s interior. Known as pyramid texts, these are the earliest significant religious compositions known from ancient Egypt.
The last of the great pyramid builders was Pepy II (2278-2184 B.C.), the second king of the sixth dynasty, who came to power as a young boy and ruled for 94 years. By the time of his rule, Old Kingdom prosperity was dwindling, and the pharaoh had lost some of his quasi-divine status as the power of non-royal administrative officials grew. Pepy II’s pyramid, built at Saqqara and completed some 30 years into his reign, was much shorter (172 feet) than others of the Old Kingdom. With Pepy’s death, the kingdom and strong central government virtually collapsed, and Egypt entered a turbulent phase known as the First Intermediate Period. Later kings, of the 12th dynasty, would return to pyramid building during the so-called Middle Kingdom phase, but it was never on the same scale as the Great Pyramids.

The Pyramids Today

Tomb robbers and other vandals in both ancient and modern times removed most of the bodies and funeral goods from Egypt’s pyramids and plundered their exteriors as well. Stripped of most of their smooth white limestone coverings, the Great Pyramids no longer reach their original heights; Khufu’s, for example, measures only 451 feet high. Nonetheless, millions of people continue to visit the pyramids each year, drawn by their towering grandeur and the enduring allure of Egypt’s rich and glorious past.

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