The Giant Camels of the Prehistoric High Arctic – Phenomena The Giant Camels of the Prehistoric High Arctic Posted Tue, 03/5/2013 Fossils can be astonishingly beautiful testaments of evolution and prehistoric time. There are few things I like better than wandering a museum’s fossil hall, admiring the skeletal architecture of a sauropod’s neck or the polished curl of an ammonite’s shell. But many, many fossils are ugly, hopelessly broken pieces of organisms past. The showroom pieces in museum halls only represent the rare, visually-magnificent few; or at least animals that paleontologists can reconstruct to the point where the remains take on an appealing cast of near-vitality. Nevertheless, even fossil crumbs have stories to tell if we know how to draw them out. One such skeletal remnant has just revealed the presence of an enormous camel that wandered forests of Canada’s High Arctic when the world was warmer. The shards of the Ellesmere camel tibia. Photo © Martin Lipman, via the Canadian Museum of Nature. The fossil is the focus of a new Nature Communications paper by paleontologist Natalia Rybczynski and colleagues.

From a purely aesthetic standpoint, the bone looks terrible. The thirty tan shards don’t even make up a full element. Altogether, laced together digitally, the scraps constitute part of a tibia from some sort of hoofed mammal. If they had been found in another deposit, the cracked fossils may not have even merited collecting, but these were the first bones found among the ancient plants of the Fyles Leaf Bed, and were apparently all that was left of a huge and hitherto undiscovered herbivore. But what kind of beast was it? In the paper, Rybczynski and coauthors point out that the anatomical landmarks on the pieces only narrow the fossil down to the level of artiodactyl – hoofed mammals with an even number of toes such as deer, cows, and camels. The size of the bone suggested that the tibia fragment came from a camel. At the time the bone was buried, about 3.4 million years ago, the largest artiodactyls in North America were camels.

By using the proportions of dromedary and Bactrian camels as a proxy, the researchers estimated that the complete tibia would have been about 22 inches long, or about 29% longer than the same bone in the extant animals. Of course, that assumed that the bone truly did belong to a camel. Morphology alone did not solve the mystery. The solution was contained within the bone itself. Collagen is a major component of bone – it’s the primary protein that makes up the flexible part of skeletal elements. Not only is collagen able to survive for a long time in the fossil record, aided in this case by the cold and dry conditions that have since developed in the Arctic, but protein profiles of the material can help distinguish mammals at the genus level. With this in mind, Rybczynski and coauthors sampled prehistoric collagen from the Ellesmere camel and compared the signature of the protein with collagen from 37 other mammal species. The collagen from the High Arctic fossils most closely resembled the profiles of dromedary camels and prehistoric camel bones found in the Yukon, thought to be members of the genus that spawned modern camel species, Paracamelus.

And the Ellesmere fossil was also a record-breaker – the bone belonged to a camel that lived about 750 miles further north than any other camel found on the continent. The environment the humped herbivore foraged over was quite a bit different than those of Ellesmere Island today. Around 3.4 million years ago, the global climate was about 35 degrees Fahrenheit warmer than at present, and the High Arctic habitats of Pliocene Ellesmere Island might have been as much as 70 degrees Fahrenheit hotter. The high latitude habitat still experienced chilly winters and almost six months of darkness, but the cold was not so harsh in the Pliocene. And, based on the plant fossils found at the same site, the ancient camels appear to have lived in boreal forests that were on the edge of the tundra. The existence of a huge camel in northern Canada might seem strange, but, in fact, the real oddity is that there are no longer any native camels in North America. The first camelids evolved in North America about 45 million years ago, and the herbivores proliferated into a variety of forms and sizes.

By about 12,000 years ago, though, the last of North America’s camels were wiped out in the continent’s megafaunal extinction, leaving only two lineages present elsewhere in the world – the dromedary and Bactrian camels of Africa and Asia, and the llamas, alpacas, guanacos, and vicuñas of South America. In the big picture of camel evolution, the Ellesmere animal was on the dromedary and Bactrian branch and relatively close to the origin of those still-living species. Rybczynski and coauthors refrain from identifying the Ellesmere camel down to genus or species. Based on the collagen evidence, the herbivore might have been a northern population of Paracamelus related to the population preserved in the younger Yukon deposits, but additional bones from both sites are needed to be sure. Still, the paltry remains of the Yukon and Ellesmere camels indicate that the hebivores were capable of surviving in northern forests, and hint that camels as we know them today carry traits that evolved to help them survive in such cold habitats.

The low-crowned teeth of modern camels might be an inheritance of ancestors that browsed in northern forests, Rybczynski and coauthors suggest, and a fatty hump that lets camels withstand harsh desert environments would have been just as advantageous in high latitude Pliocene habitats where the sky was dark for half the year. Adaptations that allow camels to thrive in deserts might have evolved in cool forests first, a testament to the flexibility of the wandering artiodactyls despite their ultimate extinction on the continent of their birth. Reference: Rybczynski, N., Gosse, J., Harington, C., Wogelius, R., Hidy, A., Buckley, M. 2013. Mid-Pliocene warm-period deposits in the High Arctic yield insights into camel evolution . Nature Communications.

4, 1550: 1-9 DOI: 10.1038/ncomms2516 Related 9 thoughts on “The Giant Camels of the Prehistoric High Arctic” Paul Braterman says: Evolutionary History | Camels The most undervalued invaluable creature Evolutionary History Source: Click Here Introduction The dromedary camel, commonly known as the one-humped camel, is one of the species in the genus Camelus , which also contains the Bactrian, two-humped camel. Camels are in the family Camelidae. Dromedaries account for approximately 90% of all the camels in the modern world (Anitei). Camel’s ancestors have developed extensively over time, and the modern camel shares the same ancestors as other modern species, as well. Read on to learn more about the history of the camel’s evolution. Source: Molly Oudekerk Eocene Epoch Though there are currently no wild camels in North America, the first 36 million years of camelids’ existence was in this area (Irwin 37).

Scientists have traced the origins of the modern camel to the Protylopus a genus containing several closely related species, which would have been found about 50 million years ago during the Eocene period in North America, perhaps around the then heavily forested area that is modern day South Dakota (Mukasa-Mugerwa). At the time this camelid was living, the climate was beginning to cool and the tropical forests were starting to recede. Protylopus was a very small animal, about the size of a modern hare. They had no hump as modern camels do, and were no more than two feet tall, about two feet long, and weighed less than 50 pounds. This animal had a simple arrangement of low-crowned teeth along the jaw. The tooth and jaw structure of Protylopus indicates that it’s diet consisted of low-level leafy forest vegetation. The front limbs were shorter than the back limbs, and each limb contained four toes. This early ancestor of camels seemed to have narrow hooves and not broad pads like the modern camel. It is likely that Protylopus had a tendency to stand on their hind legs to feed on vegetation (Irwin, 36-38).

Protylopus- Source: Click Here Oligocene and Miocene Epochs During these epochs, approximately 25 to 5 million years ago, camelids began to evolve further. It was at this point that camelids lost the two side toes, bringing them down to the two-toe modern formation. These early camelids also had no humps, similar to Protylopus (Irwin 38). One of the camelids found somewhere between the Oligocene and Miocene epochs was Poebrotherium. The Poebrotherium was larger than the Protylopus, standing about three feet tall and being sized similar to a modern goat. Poebrotherium resembled a modern day llama, with a narrow snout and long neck. Their front teeth were angled forward for the purpose of shearing vegetation. The distinguishing characteristic of camelids that existed at this time, such as Poebrotherium, were the long necks that allowed them to graze off trees and tall plants (Irwin, 39).

After Poebrotherium, camelids evolved into several different species, one of which being Procamelus, which lived through the Oligocene to the Miocene epoch from about 20 to 5 million years ago (“Fossilworks”). At this time, the earth was beginning to cool, and dry savannah was being replaced by steppe lands. Because of these environmental changes, camelids during the end of the Miocene era entering into the Pliocene epoch began to grow larger with longer necks. They also began to develop the distinctive tooth and jaw structure of the modern camel, as well as the soft, padded foot. Their teeth became longer and developed higher crowns. At this time, camelids also began to develop a pacing gait known in modern camels. Throughout this period, many camelids appeared that quickly became extinct. Several of such species were Ocydactylus, which was a camelids with a neck as long as a giraffe’s.

Also existing for short periods of time were Stenomylus, a very small camelids, similar to a gazelle, and Alticamelus which was about nineteen feet tall, and was likely the earliest of the giant camelids (Irwin 39-41). Poebrotherium- Source: Click Here Pliocene and Pleistocene Epochs During the Pliocene epoch around 2.5 million years ago, North and South America came together creating a land bridge that gave my species the opportunity to migrate. Many camelids migrated south, becoming the early ancestors of the modern domesticated llama and alpaca (Mukasa-Mugerwa). Other camelids entered into a journey across the Bering Straits to travel into Asia, and these camelids were destined to one day evolve into the modern Bactrian and dromedary camels. Scientists believe that the first camels to enter Asia through this route were Bactrians, with one-humped dromedaries evolving later from this species (Irwin 42-43). A fossil recently discovered on Ellesmere Island in the Arctic region of Canada may explain the evolutionary process from the early Poebrotherium to the modern camel.

The fossil indicates that there was a creature that was closely related to Paracamelus that lived around 5 million years ago during the middle of the Pliocene epoch, a time at which it is believed early camelids were migrating out of North America into Asia. The fossil seems to indicate that this camelid was about twice the size of a modern dromedary camel, and it’s location and time period may explain some of the adaptations found in modern camels. Dr. Natalia Rybczynski, a paleontologist with the Canadian Museum of Nature, has speculated that some of these adaptations including “their wide flat feet, large eyes, and humps for fat” (Warr), may have developed given the animal’s need to survive in an arctic climate. These recent findings shed light on the evolution of the Procamelus into the modern Camelus.

It is generally believed that the modern one-humped dromedary evolved from the two-humped bactrian species (Camelus bactrianus), which likely developed the way it did as a result of the arctic climate, with its thick coat that can withstand temperature of -20 degrees Fahrenheit and that falls away when temperatures reach 100 degrees Fahrenheit. Around 2 million years ago, the bactrian, looking very similar to the modern bactrain, standing about 7 feet tall and weighing an average of 1,800 pounds, had evolved from the Procamelus or perhaps the Paracamelus camelids that had traveled across the Bering Strait into the arctic regions of Asia (“National Geographic” ). Source: Robert Irwin, 39 At the time that the Bactrian camel entered Asia, their migration across the continent was great and varied. Some migrated as far as southern Russia, with others, such as Titanotylopus and Giganotylopus, being found in southern Ukraine about 5 million years ago. These would have been some of the camelids that were extremely large in size, likely developed to acclimate to the cold climate, as mentioned above.

As mentioned earlier, scientists believe the modern dromedary evolved from the Bactrian. Some of the evidence for this theory includes that the modern dromedary camels foetus, during prenatal development, have two humps, and also a vestigial hind hump in adult dromedaries. Given this evidence, it has been speculated that modern dromedaries evolved in the hotter, drier climates in western Asia (Mukasa-Mugerwa). Given this evolutionary evidence, it is likely that the ancestors of the modern dromedary camel traveled to the Middle Eastern and North African region. The wild dromedary would eventually become extinct in the Middle East, and only the domesticated dromedaries would survive (Irwin 41-43). During a period about 10,000 to 12,000 years ago in which most megafuna was wiped out in North America, the original camelid, Prolypotus, became extinct. However, evolution had already taken it’s course, and it is estimated that between around 3000 and 1000 BC the camel began to enter domestication (Cockrill 21).

It was by this time that the camel’s fate as the thankless perpetrator of human civilization had already been sealed. A Brief History of Camels A Brief History of Camels The camel is a large, strong desert animal. Camels can travel great distances across hot, dry deserts with little food or water. They walk easily on soft sand where trucks would get stuck, and carry people and heavy loads to places that have no roads. Camels also serve the people of the desert in many other ways. The camel carries its own built-in food supply on its back in the form of a hump. The hump is a large lump of fat that provides energy if food is hard to find. There are two chief kinds of camels: (1) the Arabian camel, also called dromedary, which has one hump, and (2) the Bactrian camel, which has two humps. In the past, hybrids (crossbreeds) of the two species were used widely in Asia. These hybrid camels had one extra-long hump and were larger and stronger than either of their parents. Camels have been domestic animals for thousands of years.

Arabian camels may once have lived wild in Arabia, but none of them live in the wild today. There are several million Arabian camels, and most of them live with the desert people of Africa and Asia. The first Bactrian camels probably lived in Mongolia and in Turkestan, which was called Bactria in ancient times. A few hundred wild Bactrian camels may still roam in some parts of Mongolia, and over a million domesticated ones live in Asia. Scientists believe that members of the camel family lived in North America at least 40 million years ago. Before the Ice Age, camels had developed into a distinct species and had moved westward across Alaska to western Asia. In Asia, two groups separated and gradually became the two chief kinds of camels known today. Meanwhile, smaller members of the camel family had moved southward from North to South America. Today, four members of the camel family live in South America: (1) alpacas, (2) guanacos, (3) llamas, and (4) vicunas. By the time Europeans went to North America, no members of the camel family had lived there for many thousands of years. No one knows why they disappeared.

The first dromedary (one-humped) camel was imported into Australia in 1840. This ill-fated animal took part in an expedition into the northern part of South Australia. It was destroyed after accidentally causing its owner's death. Later, large numbers of camels were imported into Australia for exploration and station work in the arid interior. About 250,000 camels still roam wild in the central Australian deserts. Horse and Whale evolution at College of Charleston - StudyBlue StudyBlue How many genera of horses exist today? 1 On what continent did Equus evolve? North America When and where was Equus domesticated? about 6000 years ago in central Asia What was the diet of primitive Eocene through early Miocene (between 55 and 20 My) horses? browsing on soft, leafy vegetation When and why did horses develop high crowned teeth? Grazing on the extensive grasslands of during the Miocene (25 to 15 Ma) Why did Equus become extinct in North America about 10,000 years ago? Climate Change and Hunting by Humans When were horses reintroduced to North America?

1493, on Columbus's second voyage to the New World What is the Przewalski’s wild horse? First domesticated horse, E. caballus Describe a horse that feeds by browsing? Small sized Short crowned teeth What happened to the grasses around 7 million years ago? Grasses changed from a C3 and low silica content to grasslands consist mostly of C4 and high silica content Ambulocetus We know the early ancestors of Basilosaurus lived ______________ because of the presence of _____________________. On land ------ a small pelvis and hind limbs This a tooth whale (Odontoceti) and it is able to echolocate This animal "hears" with the assistance of its lower jaw bone and a dense bone called a bulla When and why did the modern suborders of Cetaceans evolve? In the Oligocene, when there was increase in ocean productivity which provided more food for the whales to eat.

Advertisement Even-toed hoofed mammals, like camels and hippopotamuses By studying the oxygen isotope values (ratio of 18O to 16O) in the teeth of Ambulocetus, it was concluded that Ambulocetus spent the early part of it life freshwater and then migrated to the ocean. Bulla Low jaw bone developed a fat-filled canal to conduct sound back to the middle ear The whale evolution shows a transition from walking to swimming. What modifications occurred in whales so that they could become powerful swimmers reduction of the hind-limbs modification of the forelimbs and hands into flippers development of a massive tail * The material on this site is created by StudyBlue users. StudyBlue is not affiliated with, sponsored by or endorsed by the academic institution or instructor. Words From Our Students "StudyBlue is great for studying. I love the study guides, flashcards and quizzes. So extremely helpful for all of my classes!" Alice , Arizona State University "I'm a student using StudyBlue, and I can 100% say that it helps me so much. Study materials for almost every subject in school are available in StudyBlue.

It is so helpful for my education!" Tim , University of Florida "StudyBlue provides way more features than other studying apps, and thus allows me to learn very quickly!??I actually feel much more comfortable taking my exams after I study with this app. It's amazing!" Jennifer , Rutgers University "I love flashcards but carrying around physical flashcards is cumbersome and simply outdated. StudyBlue is exactly what I was looking for!" Justin , LSU Wild Camels | Wild Camel Wild Camels The Wild Camel A New and Separate Species The wild camel (Camelus ferus), a new and separate species, lives in three separated habitats in China and one in Mongolia. Thanks to the efforts of the WCPF, the wild camel was listed by the International Union for the Conservation of Nature (IUCN) in 2002 as critically endangered. There are approximately 600 surviving in China and 800 in Mongolia. The majority of these shy animals live in the Gashun Gobi (Lop Nur) desert in China and in the south-western area of the Mongolian Gobi. Evolutionary History The wild camel has a special place in evolutionary history.

They are the remnants of herds which crossed from the Arizona desert in North America over the Bering Strait land bridge 3 – 4 million years ago. Camels were domesticated 4,000 years ago, but the wild camels in the Gashun Gobi (Lop Nur) area, were a separate species and we believe avoided domestication. Moreover, research has shown that in the embryonic stage, one-humped, dromedary camels have a small second hump that does not develop. This suggests that the ancestor of all camels on earth is the wild camel, which separated from any other known species of camel 700,000 years ago. Habitat Located deep within the continental interior of the Asian continent and far from moisture laden winds, the Great Gobi Desert is one of the greatest deserts in the world, and with its variation of desert types it is unique in Asia. While vegetation is sparse, the desert itself varies from rocky mountain massifs, to the flat pavement-like areas of the extremely arid desert; stony, desert plains; poplar fringed oases; vast washed-out plains and high sand dunes.

Ancient fossils show that the Great Gobi Desert was once part of a large inland sea basin. Conservation The WCPF is currently working with government and local authorities in China and Mongolia, to try and protect the wild camel in the wild. The first phase of the work in China, was the establishment of the Lop Nur Wild Camel National Nature Reserve. Five entry checkpoints have been constructed, but more checkpoints and additional equipment for the Reserve are required. In addition is the development of a Scientific Programme, coordinating resources and scientists in China and Mongolia. This could have important implications for human survival and research. Salt Water Tolerance The wild camel has managed to survive in an area of the Gobi in China, the Gashun Gobi (Lop Nur), which was for 45 years a nuclear test site. The wild camel survived the effects of radiation from 43 atmospheric nuclear tests and is breeding naturally. In the absence of fresh water, it had also adapted to drinking salt water with a higher salt content than sea water. Domestic Bactrian camels cannot drink salt water with this degree of salt. Research to date does not show conclusively how the wild camel is absorbing and secreting the salt water.

In China, young camels after suckling for two years, can adapt to drinking salt-water. It is this adaptability which enables them to survive in the Gashun Gobi. Wild camels migrate over huge distances in pursuit of unreliable salt water sources and meagre grazing. They can survive extremes of temperature varying from -40 Celsius to plus 55 Celsius. The WCPF believes that the wild camel can yield up secrets, which will be of great benefit to man. Quick Facts Distribution The species has suffered a drastic reduction in its range. It now occurs only in three separated habitats in northwest China (Lake Lop, Taklamakan desert and the ranges of Arjin Shan) and one in the Trans-Altai Gobi desert of southwest Mongolia. Habitat The camels are migratory, and their habitat ranges from rocky mountain massifs to flat arid desert, stony planes and sand dunes. Ecology Wild camels are diurnal, sleeping at night in open spaces and foraging for food during the day. Shrubs and grass form the bulk of the diet, with the animals being well adapted to feed on thorns, dry vegetation and salty plants, which other herbivores avoid.

Excess fat is stored in the humps and used as a reserve when food is scarce. Population Estimate There are approximately 600 individuals surviving in China and 800 in Mongolia. In contrast, there are over 2 million domestic camels currently living in Central Asia. THE AGE OF MAMMALS(CENOZOIC): 65-0 M.Y.B.P. ( CENOZOIC ): 65-0 M.Y.B.P. EXTINCTION OF THE DINOSAURS (picture by NASA). At the end of the Cretaceous, 65 million years ago, not only did the dinosaurs disappear completely, but so did flying reptiles (pterosaurs), and marine reptiles (ichthyosaurs and plesiosaurs). In fact, between 60 and 80% of all animal species, including many marine forms, disappeared. Most turtles, crocodiles and primitive birds also disappeared but some survived to give rise to modern forms. There have been numerous theories to account for the extinction of dinosaurs.

But during the 1980's strong evidence was obtained to support the idea, originally proposed by Luis Alvarez, that a global catastrophe, caused by the impact of an asteroid, comet or meteorite, was responsible. Enormous amounts of debris would have been thrown into the atmosphere, making the Earth so cold and dark that cold-blooded animals like dinosaurs were unable to survive. Supporting the impact theory, about 150 Impact Craters have now been discovered on the earth. One of the most spectacular is the Barringer Crater in the Arizona desert. (picture by NASA). The Barringer crater was formed about 30,000 years ago (much too young to have anything to do with dinosaur extinction). It is 7/10 mile across and 560 feet deep, and is thought to have been caused by an iron meteorite 200 feet in diameter, weighing one million tons, that hit the earth at a speed of 30,000 mph and released an amount of energy equivalent to the most powerful nuclear devices yet made. But it is tiny compared to some older craters.

The impact responsible for the extinction of the dinosaurs would have produced a crater at least 100 miles across. The entire planet shows a 3 mm-thick layer of rock at the appropriate level (i.e. exactly at the boundary between Cretaceous and Tertiary), containing several kinds of evidence for the impact: a high concentration of the element iridium, which is rare in terrestrial rocks but common in meteorites "shocked" quartz grains showing parallel, colored markings which are an indicator of violent impact unusual amino acids, thought to be extraterrestrial in origin In North America the 3 mm layer is underlain by a similar layer 2 cm thick, and it is thickest (46 cm) at sites near to Haiti and Cuba, suggesting an impact site in the Caribbean Sea. This layer contains many glass-like beads, mm to cm in diameter, that were probably formed by melting of rocks during the impact. The molten rock would have been ejected, and then would have fallen back to earth. The composition of these layers suggests an ocean impact.

Over the past few years geologists have discovered a 200 mile-diameter submarine crater (the Chicxulub crater ), of exactly the right age but buried under 2 km of sediment, off the coast of the Yucatan peninsula in Central America. There are actually two layers, at least in western North America, suggesting that there were at least two impacts, possibly from different parts of a comet that broke up under the influence of the sun's gravitational field. It has been estimated that after the collision there was so much dust in the atmosphere that the entire planet was completely dark for 1-3 months. The lack of sunlight would have caused the extinction of many plants and animals. Among the animals, cold-blooded forms like dinosaurs would have been affected more than the warm-blooded mammals. Geologists have found that the rock in the Chicxulub crater is unusually rich in sulfur. They conclude that the impact could have produced a global sulfur dioxide fog that could have caused darkness and acid rain for over a decade. For a long time people found it hard to believe in such spectacular collisions. But impact craters are very common on many planets and the moon.

And in 1994 a comet that had already broken into 13 pieces crashed into the planet Jupiter. Although the crash was not visible from earth, we were able to see the effects of the impact soon after it happened. This made it much easier to believe that comets can crash into planets. However, not everybody believes that this kind of catastrophe finished off the dinosaurs. A meteorite impact was observed in Greenland in December 1997 . A flash of light seen from fishing trawlers turned night into day, seismic signals were detected in Norway, and satellite images showed a cloud that suddenly formed and then blew away. If you are interested in whether the Earth may be hit again by an asteroid or comet, NASA has a web site on impact hazards for you, including a list of the close predicted close approaches! EVOLUTION OF MAMMALS The survivors of the Cretaceous/Tertiary catastrophe included some small, squirrel-like animals that were to give rise to the dominant life forms of the next era - the fur-bearing, warm-blooded mammals that eventually gave rise to the human species. The period between the extinction of the dinosaurs and the present day is called the Age of Mammals or Cenozoic.

Mammals appeared on the earth long before the extinction of the dinosaurs; in fact, dinosaurs and mammals originated within 10 million years of each other, in the late Triassic about 200 million years ago. By late Cretaceous small primitive marsupials (mammals that brood their young in a pouch, like opossums), and insectivores, similar to shrews and hedgehogs, were quite abundant and widespread. But only after the dinosaurs were gone did the mammals begin their great diversification and become the dominant land animals. Then, within 10 million years, there were mammals of all kinds living in many different habitats on land, in the sea and in the air. There were herbivores, carnivores, whales, bats. During the Cenozoic there was also tremendous radiation in other groups including birds, reptiles, amphibians and fish, leading gradually up to the peak of biological diversity that occurred in the recent past. GEOGRAPHIC CHANGES AND EVOLUTION The geography of the world changed dramatically during the time when animals and plants were evolving. The major continental land masses were initially fused together into one giant continent named Pangaea during the Paleozoic era.

In the Mesozoic, Pangaea gradually broke up into the present-day continents, which have been moving apart from each other, by continental drift, ever since. This idea of continental drift was first based on the remarkably close fit between the coastlines of major continents, most notably the west coast of Africa with the east coast of South America. It is now supported by measurements, which show that the continents on either side of the Atlantic Ocean are still moving apart from one another, at the rate of several centimeters per year. Continental drift was actually a little more complicated, with the North American plate drifting around in the Pacific Ocean for quite a long time. A large chunk of the North American plate was recently found in Argentina, left there after the two continents bumped into each other then moved apart. Learn more about This Dynamic Earth . The separation of the great land mass into different continents allowed biological evolution to take quite different paths in different parts of the world. And the formation of oceanic islands, often by volcanic activity, produced many more isolated areas where evolution could experiment with different forms. Breakdown of this isolation, either by geological changes or by transport of organisms between the isolated areas, has often led to extinction of the endemic forms, and so loss of diversity.

During the Cenozoic era (the last 66 million years), there was a gradual lowering of temperatures as well as the gradual establishment of different climatic zones of the earth -the tropics, the temperate zones and the cool climates of the higher latitudes. The culmination of the cooling trend was the Pleistocene epoch, or Great Ice Age, of the last 1.8 million years. During this time vast expanses of North America and Eurasia were periodically covered with enormous continental glaciers. These glaciers advanced during the four ice ages (glacial periods) and retreated during the three interglacials. We are probably now living in the fourth interglacial stage. During the glacial periods the sea level became much lower because so much water was converted to ice. Consequently land bridges, especially the Bering land bridge across the Bering Sea joining Asia with North America, became available for animal migrations. During the Cenozoic the mammals reached their peak of evolution, producing a tremendous variety of species, many of them very large. The segment of the fauna containing these large creatures (those weighing more than about 100 pounds) is called the Megafauna. Most of these animals are extinct.

EVOLUTION OF MAMMALS ON DIFFERENT CONTINENTS Mammalian evolution in the Northern hemisphere. We know about the Pleistocene mammals not only from fossils but also from carcasses, especially of the woolly rhinoceros, which have been found in petroleum deposits in Romania. Mammoths, complete with flesh, hair and stomach contents, have been found frozen in the ice in Siberia. Some members of the Pleistocene megafauna were restricted to certain areas. For example, the woolly rhinoceros, giant deer, the moose-like giraffe shown in the slide, and the cave bear were found only in Eurasia and Africa. But the Bering land bridge has been present intermittently through the entire Cenozoic period. It allowed the entry of many of the large mammals that were to subsequently dominate the North American fauna, including the woolly mammoth, imperial mammoth, mastodon, bison, deer, sheep, cattle and many large carnivores. Slide shows a reconstruction of a Pleistocene scene in North America. Notice the saber-toothed cat with its enormous canine teeth. The Bering land bridge also allowed animals that evolved in North America to colonize Asia.

Horses and camels originated in North America and from here spread to Asia and South America. They subsequently (8,000 years ago for horses) became extinct in North America. Horses did not reappear in this country until Columbus' second voyage in 1493. See slide of the evolutionary history of the horse - one of the most complete fossil series available, often used as a classical example of evolution. Mammalian Evolution in South America. At the beginning of the Cenozoic era, there was a land bridge between North and South America, as there is today. This land bridge allowed primitive mammals to colonize South America from the North. This land link was later (during the Eocene) broken, and those animals which had settled in South America then evolved in complete isolation from the rest of the world. Over about 40 million years these primitive groups diversified in many unique ways. The placental mammals (those that carry their young in a uterus, using a placenta to provide nutriment) of South America evolved as herbivores, many of them large and slow moving, like the ground sloth Megatherium which reached up to 29 feet tall when standing upright on its hind legs.

The ground sloth was the largest and heaviest of all land mammals (there may have been a sighting in 1994!). Other South American mammals evolved single-digit feet ending in strong hoofs, exactly like those of modern horses, and others possessed a well-developed trunk and massive legs like the elephant's. These are examples of convergent evolution. The marsupials (mammals that carry their young in a pouch, like kangaroos) evolved in the other direction, becoming carnivores. One of them bore an amazingly close resemblance to the independently evolved saber-toothed cat of North America, which was a placental mammal. This is another example of convergent evolution. New forms of wildlife continued to arrive in South America even after the continent was cut off from North America. These "island hoppers" were able to cross the stretches of water then separating the continents because of their small size and/or their ability to swim. They included primates which gave rise to the New World monkeys, including howler monkey, marmosets, capuchins, woolly monkeys and spider monkeys; and rodents which evolved into a number of families, several of which are found nowhere else in the world.

These include the capybara, the agouti, the coypu, the cavy (Guinea pig) and the chinchilla. In South America there is a greater variety of rodents than anywhere else in the world. The Invasion of South America. In the upper Pliocene, 3 million years ago, the isthmus of Panama reappeared as a result of changes in the earth's crust. This was a disaster for many of the animals that had evolved in isolation in South America. South America was invaded by deer, camels, raccoons, tapirs, horses, mastodons, bears, peccaries, rabbits, shrews, cats, dogs, weasels and rodents. For some reason these animals were able to displace many of the South American species, driving many of them to extinction. Some of the new arrivals (e.g. mastodons and horses) survived only for a brief period. Others were very successful, for example the camel family which has given rise to the vicunas, guanacos, alpacas and llamas. The camels as well as the horses subsequently became extinct in North America where they originated.

Another group of uniquely South American mammals, the edentates (sloths, armadillos and anteaters), survived the competition with the invaders and are still abundant in South America. The armadillos, like their primitive ancestors, are armor-plated mammals in which the armor plating is composed of separate shields and hinged bands. But the related species of one extinct group, the glyptodonts, had a single-piece carapace similar to that of tortoises. These glyptodonts, some of which were as big as a Volkswagen and armored like a tank, survived up until quite recent times and may have been hunted by primitive Indian tribes; piles of glyptodont bones have been found alongside various human artifacts. A few of the animals that had evolved in South America migrated in the reverse direction, becoming established in North as well as South America: the anteater, porcupine, opossum and armadillo. South America provides a spectacular example of how evolution can take off in novel directions when a region is isolated for a long enough period of time. It also provides a dramatic lesson in how apparently well adapted species can often be driven to extinction when exotic species (those coming from outside) are introduced.

Mammalian Evolution in Australia. The mammalian fauna of Australia also evolved in isolation since the early Cenozoic (Eocene), but in this case the isolation remained complete. For unknown reasons, Australia was apparently originally populated entirely by marsupials rather than placental mammals. Today the native mammalian fauna of Australia is made up of marsupials of many different kinds, that occupy ecological niches similar to those occupied by placental mammals in other parts of the world. Evolution produced marsupial mice, a marsupial mole, and, most impressive, a marsupial wolf (almost extinct) and a marsupial lion (extinct), all of which bear striking resemblances to the corresponding placental forms. These are examples of convergent evolution. Other Australian marsupials occupy the same ecological niches as certain placental mammals in other continents, but are rather different in appearance. For example the wallabies and kangaroos occupy the niche of browsing and grazing mammals which is occupied by the ungulates (hoofed mammals) in other parts of the world. The Koala, a tree-climbing, slow-moving herbivore, occupies the same niche as the tree sloths of South America.

The Koala is now being considered for Endangered Species listing in this country; its population has plummeted because of destruction of eucalyptus forests in Australia. Around Christmas 2001 over 100 fires, most deliberately set, burned 1.2 million acres in southeast Australia, including huge areas of koala habitat. Thousands of koalas were lost out of less than 100,000 remaining. Australia did produce some giant forms such as giant kangaroos, which are now extinct. EVOLUTION OF HUMANS The Pleistocene is the time when humans evolved in the old world. The first hominids (i.e. creatures more closely related to humans than to apes) lived from 4 to 3 million years ago. These (called Australopithecus) lived in Africa. They had a protruding jaw, prominent eyebrow ridges and a small braincase. They walked upright. 1.8 million years ago, Homo erectus appeared in Africa, with a brain as big as the smallest modern human brain. H. erectus differed from modern humans by the prominent brow ridges and receding chin.

They made sophisticated stone hand-axes with sharp edges, possibly made spear points, and probably used fire. They spread over Africa and Asia and survived until about 400,000 years ago. The first fossils that are classified in the modern species Homo sapiens date from about 200,000 years ago (Nat. Geog. , Jan. 1996) and are called neanderthals (a subspecies of Homo sapiens). The neanderthals still looked primitive, with prominent brow ridges, low foreheads, and receding chins, but their brains were, on average, slightly larger than ours. They hunted woolly rhino and cave-bear and disappeared about 30,000 years ago. About 30,000 years ago, fully modern humans called Cro-Magnon evolved from the neanderthal-like forms of the Near East and spread into Asia and Europe, rapidly replacing the more primitive neanderthals. They had domed heads, smooth brows, and prominent chins.

They made precision tools, including definite spearheads, and they produced spectacular works of wildlife art on the walls of caves, which provide some glimpses of how the big game was hunted - with spears and rocks and probably also traps and fire. One painting shows an eviscerated bison about to gore a human. How do we know the ages of things? Radiocarbon dating HUMANS ENTER THE NEW WORLD During the last ice age (20-11,000 years ago), so much sea water was frozen into the ice caps that the sea level fell about 300 feet. This exposed a 1,000 mile-wide strip of land connecting the two continents called the " Bering Land Bridge ", but at the glacial maximum of 18-20,000 years ago the continental glacier (the Laurentide Glacier) stretched all the way to the Pacific Ocean, blocking animal and human movement between the continents. At about 14,000 years ago a warming trend opened up an ice-free corridor between the main Laurentide glacier and the smaller Cordilleran ice sheet along the coast.

This made it possible for early humans to migrate from Asia into the unglaciated lands of North America. Then during the present interglacial, melting ice caused the sea level to rise, cutting off the land connection between Asia and North America. Early humans are believed to have arrived in North America about 11,500 years ago, soon after the ice-free corridor opened up. These people are known as the Clovis people, named after the town in New Mexico where their distinctive spear points were found in 1932. Clovis points have been found in association with mammoth bones at several locations in North America, suggesting that the Clovis people hunted these animals. At some sites (e.g. Murray Springs ) bones of other large mammals have been found, including Horse, Camels, Bison, Lion, and Dire wolf. It has long been assumed that the Clovis people were the ancestors of American Indians, but this assumption is now being questioned. There are no human skeletal remains from the earliest arrivals, and only about ten sets of remains more than 9,000 years old.

Surprisingly, physical anthropologists have concluded that the skulls of two of the oldest skeletons ( Spirit Cave Man from Nevada, 9,400 years old and Kennewick Man found in Washington State in 1996, 9,300 years old) are quite different from those of modern American Indians. Their cranial vaults are long and narrow rather than round, their faces are slender rather than broad, and they do not have prominent cheekbones. These skeletons resemble those of Polynesians, Europeans, and the Ainu of Japan, more than they resemble American Indians, leading to the idea that American Indians may be derived from one or more distinct groups of settlers arriving some time after the Clovis culture. The third specimen (Wizards Beach Man from Nevada, 9,200 years old), is more similar to contemporary American Indians. The base sequence of mitochondrial DNA (mDNA) from living American Indian populations is similar to that of samples from Asia and Siberia, confirming the earlier conclusions from archeology. But some mutations in American Indian mDNA are found elsewhere only among the aboriginal populations in Southeast Asia and in the islands of Melanesia and Polynesia , providing another clue for a possible immigration by sea.

Unfortunately, three laboratories were unable to obtain any DNA evidence from Kennewick man. The legal requirement to return human remains to tribes that can show an affiliation, so that they can be reburied, has led to enormous controversy over how much scientific analysis of these samples will be possible. In the case of Kennewick man, after the failure to obtain DNA evidence the Department of the Interior in 2000 decided to abandon scientific research and give the skeleton to five Indian tribes who jointly claimed the remains for reburial. Some evidence suggests human occupation of both North and South America earlier than the Clovis culture , leading to several fascinating alternative possibilities. Several sites in the southeastern part of the U.S. have been dated much earlier than Clovis, but the evidence from most of these sites has been seriously questioned for technical reasons. However, one remarkably informative early settlement in Monte Verde, Chile, makes it difficult to completely accept the traditional "Clovis-first" view. The site includes remains of dwellings and stone tools (not Clovis points) as well as medicinal plants, and dates from 12,500 years ago.

This early date has led to suggestions that early migrants may have reached and explored North and South America by boat, rather than on foot. This would have allowed them to avoid the glacial barrier, it would have been faster, and it might have been easier, since food would have been plentiful. Archeological evidence shows that Pacific people used boats as early as 25,000 or even 40,000 years ago, so the technology may have been available. There were many unglaciated pieces of coastline that would have allowed breaks in the sea journey, and there are several sites along the coast of Canada, California, Peru, Ecuador, and Chile that show evidence for human occupation between 10,000 and 12,000 years ago. Unfortunately the sea level is much higher now than then, so much of the archeological evidence for seafaring at that time may now be deeply submerged and difficult to find. Back to: When and Where Were Camels Domesticated? By K. Kris Hirst Updated June 22, 2015.

There are two Old World species of quadruped animal of the deserts of the world known as the camel, and four species in the New World, all of which have implications for archaeology and all of which effectively changed the different cultures which domesticated them. Camelidae evolved in what is today North America, some 40-45 million years ago, and the divergence between what would become Old and New World camel species occurred in North America about 25 million years ago. During the Pliocene epoch, the Camelini (camels) spread into Asia, and the Lamini (llamas) migrated into South America: their ancestors survived for another 25 million years until they became extinct in North America during the mass megafaunal extinctions at the end of the last ice age. Old World Species Two species of camels are known in the modern world. Asian camels were (and are) used for transportation, but also for their milk, dung, hair and blood, all of which were used for various purposes by nomadic pastoralists of the deserts.

continue reading below our video 10 Facts About the Titanic That You Don't Know The Bactrian camel (Camelus bactrianus) (two humps) resides in central Asia, especially Mongolia and China. The dromedary camel (Camelus dromedarius) (one hump) is found in North Africa, Arabia and the Middle East. New World Species There are two domesticated species and two wild species of camels, all of them located in Andean South America. South American camels were also definitely used for food (they were likely the first meat used in c'harki ) and transport, but they also were prized for their ability to navigate in the high altitude arid environments of the Andes mountains, and for their wool, which engendered an ancient textile art.

The guanaco (Lama guanicoe) is the largest of the wild species, and it is the wild form of the alpaca (Lama pacos L.) The vicuna (Vicugna vicugna), daintier than the guanaco (tribe Lamini) species, is the wild form of the domestic llama (Lama glama L.) See the embedded links above for more details about the different species. Sources This article is part of the Guide to Animal Domestication . Compagnoni B, and Tosi M. 1978. The camel: Its distribution and state of domestication in the Middle East during the third millennium B.C. in light of the finds from Shahr-i Sokhta. Pp. 119–128 in Approaches to Faunal Analysis in the Middle East, edited by R.H. Meadow and M.A. Zeder. Peabody Museum Bulletin no 2, Peabody Museum of Archaeology and Ethnology, New Haven, CT. Gifford-Gonzalez D, and Hanotte O. 2011. Domesticating Animals in Africa: Implications of Genetic and Archaeological Findings.

Journal of World Prehistory 24(1):1-23. Grigson C, Gowlett JAJ, and Zarins J. 1989. The Camel in Arabia: A Direct Radiocarbon Date, Calibrated to about 7000 BC. Journal of Archaeological Science 16:355-362. doi:10.1016/0305-4403(89)90011-3 Ji R, Cui P, Ding F, Geng J, Gao H, Zhang H, Yu J, Hu S, and Meng H. 2009. Monophyletic origin of domestic bactrian camel (Camelus bactrianus) and its evolutionary relationship with the extant wild camel (Camelus bactrianus ferus). Animal Genetics 40(4):377-382.

doi: 10.1111/j.1365-2052.2008.01848.x Weinstock J, Shapiro B, Prieto A, Marín JC, González BA, Gilbert MTP, and Willerslev E. 2009. The Late Pleistocene distribution of vicuñas (Vicugna vicugna) and the “extinction” of the gracile llama (“Lama gracilis”): New molecular data. Quaternary Science Reviews 28(15–16):1369-1373. doi:10.1016/j.quascirev.2009.03.008 Zeder MA, Emshwiller E, Smith BD, and Bradley DG. 2006. Documenting domestication: the intersection of genetics and archaeology. Trends in Genetics 22(3):139-155. doi:10.1016/j.tig.2006.01.007

Question: In what continent did camels first evolve?
Answer: North America