 |
|
Evolution study tightens human-chimp connection
January 24, 2006Study also finds human evolution slower than apes
Scientists at the Georgia Institute of Technology have found genetic evidence that seems to support a controversial hypothesis that humans and chimpanzees may be more closely related to each other than chimps are to the other two species of great apes - gorillas and orangutans. They also found that humans evolved at a slower rate than apes.
Appearing in the January 23, 2006 issue of the Proceedings of the National Academy of Sciences, biologist Soojin Yi reports that the rate of human and chimp molecular evolution - changes that occur over time at the genetic level - is much slower than that of gorillas and orangutans, with the evolution of humans being the slowest of all.
As species branch off along evolutionary lines, important genetic traits, like the rate of molecular evolution also begin to diverge. They found that the speed of this molecular clock in humans and chimps is so similar, it suggests that certain human-specific traits, like generation time, began to evolve one million years ago-very recently in terms of evolution. The amount of time between parents and offspring is longer in humans than apes. Since a long generation time is closely correlated with the evolution of a big brain, it also suggests that developmental changes specific to humans may also have evolved very recently.
In a large-scale genetic analysis of approximately 63 million base pairs of DNA, the scientists studied the rate at which the base pairs that define the differences between species were incorrectly paired due to errors in the genetic encoding process, an occurrence known as substitution. "For the first time, we've shown that the difference in the rate of molecular evolution between humans and chimpanzees is very small, but significant, suggesting that the evolution of human-specific life history traits is very recent," said Yi.
Most biologists believe that humans and chimpanzees had a common ancestor before the evolutionary lines diverged about 5-7 million years ago. According to the analysis, one million years ago the molecular clock in the line that became modern humans began to slow down. Today, the human molecular clock is only 3 percent slower than the molecular clock of the chimp, while it has slowed down 11 percent from the gorilla's molecular clock.
This slow down in the molecular clock correlates with a longer generation time because substitutions need to be passed to the next generation in order to have any lasting effect on the species,
"A long generation time is an important trait that separates humans from their evolutionary relatives," said Navin Elango, graduate student in the School of Biology and first author of the research paper. "We used to think that apes shared one generation time, but that's not true. There's a lot more variation. In our study, we found that the chimpanzee's generation time is a lot closer to that of humans than it is to other apes."
The results also confirm that there is very little difference in the alignable regions of the human and chimp genomes. Taken together, the study's findings suggest that humans and chimps are more closely related to each other than the chimps are to the other great apes.
"I think we can say that this study provides further support for the hypothesis that humans and chimpanzees should be in one genus, rather than two different genus' because we not only share extremely similar genomes, we share similar generation time," said Yi.
Even though the 63 million base pairs they studied is a large sample, it's still a small part of the genome, Yi said. "If we look at the whole genome, maybe it's a different story, but there is evidence in the fossil record that this change in generation time occurred very recently, so the genetic evidence and the fossil data seem to fit together quite well so far."
Georgia Institute of Technology
As species branch off along evolutionary lines, important genetic traits, like the rate of molecular evolution also begin to diverge. They found that the speed of this molecular clock in humans and chimps is so similar, it suggests that certain human-specific traits, like generation time, began to evolve one million years ago-very recently in terms of evolution. The amount of time between parents and offspring is longer in humans than apes. Since a long generation time is closely correlated with the evolution of a big brain, it also suggests that developmental changes specific to humans may also have evolved very recently.
In a large-scale genetic analysis of approximately 63 million base pairs of DNA, the scientists studied the rate at which the base pairs that define the differences between species were incorrectly paired due to errors in the genetic encoding process, an occurrence known as substitution. "For the first time, we've shown that the difference in the rate of molecular evolution between humans and chimpanzees is very small, but significant, suggesting that the evolution of human-specific life history traits is very recent," said Yi.
Most biologists believe that humans and chimpanzees had a common ancestor before the evolutionary lines diverged about 5-7 million years ago. According to the analysis, one million years ago the molecular clock in the line that became modern humans began to slow down. Today, the human molecular clock is only 3 percent slower than the molecular clock of the chimp, while it has slowed down 11 percent from the gorilla's molecular clock.
This slow down in the molecular clock correlates with a longer generation time because substitutions need to be passed to the next generation in order to have any lasting effect on the species,
"A long generation time is an important trait that separates humans from their evolutionary relatives," said Navin Elango, graduate student in the School of Biology and first author of the research paper. "We used to think that apes shared one generation time, but that's not true. There's a lot more variation. In our study, we found that the chimpanzee's generation time is a lot closer to that of humans than it is to other apes."
The results also confirm that there is very little difference in the alignable regions of the human and chimp genomes. Taken together, the study's findings suggest that humans and chimps are more closely related to each other than the chimps are to the other great apes.
"I think we can say that this study provides further support for the hypothesis that humans and chimpanzees should be in one genus, rather than two different genus' because we not only share extremely similar genomes, we share similar generation time," said Yi.
Even though the 63 million base pairs they studied is a large sample, it's still a small part of the genome, Yi said. "If we look at the whole genome, maybe it's a different story, but there is evidence in the fossil record that this change in generation time occurred very recently, so the genetic evidence and the fossil data seem to fit together quite well so far."
Georgia Institute of Technology
Human Evolution Current Events and Human Evolution News RSS'Hobbits' are a new human species -- according to the statistical analysis of fossils
Researchers from Stony Brook University Medical Center in New York have confirmed that Homo floresiensis is a genuine ancient human species and not a descendant of healthy humans dwarfed by disease.
Snail fossils suggest semiarid eastern Canary Islands were wetter 50,000 years ago
Fossil land snail shells found in ancient soils on the subtropical eastern Canary Islands show that the Spanish archipelago off the northwest coast of Africa has become progressively drier over the past 50,000 years.
2-million-year-old evidence shows tool-making hominins inhabited grassland environments
In an article published in the open-access, peer-reviewed journal PLoS ONE on October 21, 2009, Dr Thomas Plummer of Queens College at the City University of New York, Dr Richard Potts of the Smithsonian Institution National Museum of Natural History and colleagues report the oldest archeological evidence of early human activities in a grassland environment, dating to 2 million years ago.
Are humans still evolving? Absolutely, says a new analysis of a long-term survey of human health
Although advances in medical care have improved standards of living over time, humans aren't entirely sheltered from the forces of natural selection, a new study shows.
Chimpanzees help each other on request but not voluntarily
The evolution of altruism has long puzzled researchers and has mainly been explained previously from ultimate perspectives-I will help you now because I expect there to be some long-term benefit to me.
Kent State University Professor C. Owen Lovejoy helps unveil oldest hominid skeleton
Throw out all those posters and books that depict an ape evolving into a human being, says Kent State University Professor of Anthropology Dr. C. Owen Lovejoy.
Ardi displaces Lucy as oldest hominid skeleton
Nearly 17 years after plucking the fossilized tooth of a new human ancestor from a pebbly desert in Ethiopia, an international team of scientists today announced their reconstruction of a partial skeleton of the hominid, Ardipithecus ramidus, which they say revolutionizes our understanding of the earliest phase of human evolution.
Evolution coup: Study reveals how plants protect their genes
Unlike animals and humans, plants can't run and hide when exposed to stressful environmental conditions. So how do plants survive?
Piece from childhood virus may save soldiers' lives
A harmless shard from the shell of a common childhood virus may halt a biological process that kills a significant percentage of battlefield casualties, heart attack victims and oxygen-deprived newborns.
Tiny ancient shells point to earliest fashion trend
Shell beads newly unearthed from four sites in Morocco confirm early humans were consistently wearing and potentially trading symbolic jewellery as early as 80,000 years ago.
More Human Evolution Current Events and Human Evolution News Articles
 |
The Complete World of Human Evolution by Chris Stringer (Author), Peter Andrews (Author) A compelling, authoritative, and superbly illustrated account of the rise and eventual domination of our species. Human domination of the earth is now so complete that it is easy to forget how recently our role in the history of the planet began: the earliest apes evolved around twenty million years ago, yet Homo sapiens has existed for a mere 150,000 years. In the intervening period, many species of early ape and human have lived and died out, leaving behind the fossilized remains that have helped to make the detailed picture of our evolution revealed here. This exciting, up-to-the-minute account is divided into three accessible sections. "In Search of Our Ancestors" examines the contexts in which fossilized remains have been found and the techniques used to study them. "The... |
 |
Smithsonian Intimate Guide to Human Origins by Carl Zimmer (Author) From the savannas of Africa to modern-day labs for biomechanical analysis and molecular genetics, Smithsonian Intimate Guide to Human Origins reveals how anthropologists are furiously redrawing the human family tree. Their discoveries have spawned a host of new questions: Should chimpanzees be included as a human species? Was it the physical difficulty of human childbirth that encouraged the development of social groups in early human species? Did humans and Neanderthals interbreed? Why did humans supplant Neanderthals in the end? In answering such questions, Smithsonian Intimate Guide to Human Origins sheds new light on one of the most important questions of all: What makes us human? |
 |
The Last Human: A Guide to Twenty-Two Species of Extinct Humans by G. J. Sawyer (Author), Viktor Deak (Author), Esteban Sarmiento (Author), Richard Milner (Author), Ian Tattersall (Introduction), Maeve Leakey (Introduction), Donald C. Johanson (Introduction) This book tells the story of human evolution, the epic of Homo sapiens and its colorful precursors and relatives. The story begins in Africa, six to seven million years ago, and encompasses twenty known human species, of which Homo sapiens is the sole survivor. Illustrated with spectacular, three-dimensional scientific reconstructions portrayed in their natural habitat developed by a team of physical anthropologists at the American Museum of Natural History and in concert with experts from around the world, the book is both a guide to extinct human species and an astonishing hominid family photo album. The Last Human presents a comprehensive account of each species with information on its emergence, chronology, geographic range, classification, physiology, lifestyle, habitat,... |
 |
Human Evolution: A Very Short Introduction (Very Short Introductions) by Bernard Wood (Author) The recent discovery of the diminutive Homo floresiensis (nicknamed "the Hobbit") in Indonesia has sparked new interest in the study of human evolution. In this Very Short Introduction, renowned evolutionary scholar Bernard Wood traces the history of paleoanthropology from its beginnings in the eighteenth century to today's latest fossil finds. Along the way we are introduced to the lively cast of characters, past and present, involved in evolutionary research. Although concentrating on the fossil evidence for human evolution, the book also covers the latest genetic evidence about regional variations in the modern human genome that relate to our evolutionary history. Wood draws on over thirty years of experience to provide an insiders view of the field, and demonstrates that our... |
 |
The First Human: The Race to Discover Our Earliest Ancestors by Ann Gibbons (Author) In this dynamic account, award-winning science writer Ann Gibbons chronicles an extraordinary quest to answer the most primal of questions: When and where was the dawn of humankind? Following four intensely competitive international teams of scientists in a heated race to find the “missing link”–the fossil of the earliest human ancestor–Gibbons ventures to Africa, where she encounters a fascinating array of fossil hunters: Tim White, the irreverent Californian who discovered the partial skeleton of a primate that lived 4.4 million years ago in Ethiopia; French paleontologist Michel Brunet, who uncovers a skull in Chad that could date the beginnings of humankind to seven million years ago; and two other groups–one led by zoologist Meave Leakey, the other by British... |
 |
Human Evolution: Trails from the Past by Camilo J. Cela-Conde (Author), Francisco J. Ayala (Author) Human Evolution provides a comprehensive overview of hominid evolution, synthesizing data and approaches from fields as diverse as physical anthropology, evolutionary biology, molecular biology, genetics, archaeology, psychology, and philosophy. The book begins with chapters on evolution, population genetics, systematics, and the methods for constructing evolutionary trees. These are followed by a comprehensive review of the fossil history of human evolution since our divergence from the apes. Subsequent chapters cover more recent data, both fossil and molecular, relating to the evolution of modern humans. A final section describes the evolution of culture, language, art, and morality. The authors are leading experts in two complementary fields of scholarship: physical... |
 |
Human Evolution: An Illustrated Introduction by Roger Lewin (Author) The brief length and focused coverage of Human Evolution: An Illustrated Introduction have made this best-selling textbook the ideal complement to any biology or anthropology course in which human evolution is taught. The text places human evolution in the context of humans as animals, while also showing the physical context of human evolution, including climate change and the impact of extinctions. Chapter introductions, numerous drawings and photographs, and an essential glossary all add to the accessibility of this text.The fifth edition has been thoroughly updated to include coverage of the latest discoveries and perspectives, including: · New early hominin fossils from Africa and Georgia, and their implications |
 |
Just The Facts: Prehistoric Man - Human Evolution Starring: Just the Facts Directed By: Cerebellum Corporation Beginning in the late nineteenth century and throughout the twentieth century, geologists, archaeologists and paleoanthropologists have given the world evidence of the physical and cultural development of humans. Amazing discoveries continue into the twenty-first century, broadening our knowledge of our earliest ancestors and pushing the date of the first appearance of humans to millions of years before recorded history. In Part 1 of "Prehistoric Man," viewers come face to face with fascinating ancient creatures who looked something like apes but walked upright. We learn how they lived in their foraging societies; what their life may have been like; how they fashioned tools out of stone, wood and bone; and how scientists determine the age of the fossils that give us windows to their... |
 |
The 10,000 Year Explosion: How Civilization Accelerated Human Evolution by Gregory Cochran (Author), Henry Harpending (Author) Resistance to malaria. Blue eyes. Lactose tolerance. What do all of these traits have in common? Every one of them has emerged in the last 10,000 years.
|
 |
The Human Story: Where We Come From & How We Evolved by Charles Lockwood (Author) Anthropology professor Charles Lockwood tells the amazing story of human evolution in a concise and compelling introduction to all our ancestors and extinct relatives. He draws on the explosion of discoveries made over the past 20 years to demystify the fascinating cast of characters who hold the secret to our origins, and describes the main sites, individual fossils, key scientific breakthroughs, and latest research that have fed our knowledge. With the help of a rich assortment of photographs, reconstructions, and maps, Lockwood takes us from the earliest hominins, who date back six or seven million years ago, to contemporary homo sapiens, providing the basic facts about each species: what it looked like, what it ate, how and when it lives, and how we know this information. Created... |
| © 2009 BrightSurf.com |