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Lottie Peppers

A phylogenomic data-driven exploration of viral origins and evolution | Science Advances - 1 views

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    The origin of viruses remains mysterious because of their diverse and patchy molecular and functional makeup. Although numerous hypotheses have attempted to explain viral origins, none is backed by substantive data. We take full advantage of the wealth of available protein structural and functional data to explore the evolution of the proteomic makeup of thousands of cells and viruses. Despite the extremely reduced nature of viral proteomes, we established an ancient origin of the "viral supergroup" and the existence of widespread episodes of horizontal transfer of genetic information. Viruses harboring different replicon types and infecting distantly related hosts shared many metabolic and informational protein structural domains of ancient origin that were also widespread in cellular proteomes. Phylogenomic analysis uncovered a universal tree of life and revealed that modern viruses reduced from multiple ancient cells that harbored segmented RNA genomes and coexisted with the ancestors of modern cells. The model for the origin and evolution of viruses and cells is backed by strong genomic and structural evidence and can be reconciled with existing models of viral evolution if one considers viruses to have originated from ancient cells and not from modern counterparts.
Lottie Peppers

What Was The Miller-Urey Experiment? - YouTube - 0 views

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    The Miller-Urey experiment was the first attempt to scientifically explore ideas about the origin of life. Stanley Miller simulated conditions thought be common on the ancient Earth. The purpose was to test the idea that the complex molecules of life (in this case, amino acids) could have arisen on our young planet through simple, natural chemical reactions. The experiment was a success in that amino acids, the building blocks of life, were produced during the simulation. The finding was so significant that it kick started an entirely new field of study: Prebiotic Chemistry. Scientists now have reason to believe that the gases used in the Miller-Urey simulation were not actually the same as those of the ancient atmosphere. Because of this, many experiments have since been done, testing a wide variety of atmospheres and different environmental conditions. The results are overwhelming: the molecules of life can form under a wide variety of ancient Earth-like conditions. Many questions about the origin of life remain to be answered but these findings give strong support to the idea that the first living cells on Earth may have emerged from natural chemical reactions.
Lottie Peppers

Ancient Viruses, Once Foes, May Now Serve as Friends - NYTimes.com - 0 views

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    Our genomes are riddled with the detritus of ancient viruses. They infected our hominid ancestors tens of millions of years ago, inserting their genes into the DNA of their hosts. Today, we carry about 100,000 genetic remnants of this invasion. So-called endogenous retroviruses make up 8 percent of the human genome.
Lottie Peppers

Genetic mysteries of the biggest trees - San Francisco Chronicle, 2017-09-26 - 0 views

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    Redwood trees, those ancient living monuments to California's past, are as mysterious to science as they are magnificent, so a team of researchers led by a San Francisco conservation group is attempting to unlock the genetic secrets of the towering conifers. Scientists affiliated with the nonprofit Save the Redwoods League are attempting for the first time to sequence the genomes of coast redwood trees and their higher-elevation cousins, the giant sequoias, a complex and expensive undertaking that experts hope will help preserve the trees' ancient groves as the climate changes over the next century.
Lottie Peppers

Microbes Deep under Seafloor Reflect Ancient Land Origins - Scientific American - 0 views

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    Microbes 2,500 meters below the seafloor in Japan are most closely related to bacterial groups that thrive in forest soils on land, suggesting that they might be descendants of ones that survived when their terrestrial habitat was flooded 20 million years ago
Lottie Peppers

Christina Warinner: Tracking ancient diseases using ... plaque | Talk Video | TED.com - 0 views

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    Imagine what we could learn about diseases by studying the history of human disease, from ancient hominids to the present. But how? TED Fellow Christina Warinner is an achaeological geneticist, and she's found a spectacular new tool - the microbial DNA in fossilized dental plaque.
Lottie Peppers

Ancient fossil may rewrite fish family tree | Science/AAAS | News - 0 views

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    When it comes to charting the tree of life, the most important difference between humans and sharks isn't limbs versus fins or even lungs versus gills. It all comes down to our skeletons. Sharks' skeletons are made of cartilage, placing them along with rays and skates in a group of jawed vertebrates called cartilaginous fish. Humans-along with most other living vertebrates-belong to the same group as bony fish, whose skeletons are made of bone. Scientists knew that these groups diverged more than 420 million years ago, but what the last common ancestor looked like remained a mystery. Now, new discoveries inside the head of a small fossil fish from Siberia may provide some clues.
Lottie Peppers

A horse is a horse, of course, of course -- except when it isn't: Analysis of ancient D... - 0 views

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    Scientists have discovered a previously unrecognized genus of extinct horses that roamed North America during the last ice age. The new findings are based on an analysis of ancient DNA from fossils of the enigmatic 'New World stilt-legged horse'
Lottie Peppers

Human Ancestor Went out on a Limb - 0 views

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    2 minute animation, (includes full body animation rendition of Australopithicus) A recent study of fossil shoulder bones from a human ancestor reveals that this ancient relative was still well adapted to living in trees, even after the evolution of bipedalism. Studying features like these helps scientists to better understand when modern humans moved away from a partly arboreal lifestyle and transitioned to living exclusively on the ground.
Lottie Peppers

Giant, ancient viruses are thawing out in Siberia - and they're changing everything we ... - 0 views

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    Last month, researchers announced they were studying a 30,000-year-old giant virus called Mollivirus sibericum that they found in melted Siberian permafrost. The virus was functional and able to infect amoeba. This isn't the first time researchers have found big viruses that have challenged what we thought we knew about the tiny invaders. Mimivirus, discovered in 2003, has 1,200 genes and is twice the width of traditional viruses.
Lottie Peppers

DNA secrets of Ice Age Europe unlocked - BBC News - 0 views

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    Researchers analysed the genomes of 51 individuals who lived between 45,000 years ago and 7,000 years ago. The results reveal details about the biology of these early inhabitants, such as skin and eye colour, and how different populations were related. It also shows that Neanderthal ancestry in Europeans has been shrinking over time, perhaps due to natural selection. The study in Nature journal shines a torchlight over some 40,000 years of prehistory, showing that ancient patterns of migration were just as complex as those in more recent times.
Lottie Peppers

Adding Branches to the Human Family Tree - NYTimes.com - 0 views

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    n Wednesday, it happened again. Yohannes Haile-Selassie of the Cleveland Museum of Natural History and his colleagues reported finding a jaw in Ethiopia that belonged to an ancient human relative that lived some time between 3.3 and 3.5 million years. They argue that the jaw belongs to an entirely new species, which they dubbed Australopithecus deyiremeda.
Lottie Peppers

What did dogs teach humans about diabetes? - Duncan C. Ferguson | TED-Ed - 0 views

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    Diabetes has a history dating back to Ancient Greece. Our treatment of it, however, is more recent and was originally made possible with the help of man's best friend. Due to physiological traits shared with humans, dogs have saved countless lives through the discovery of insulin. Duncan C. Ferguson shares the story of the canine's great contribution to man -- and how we can all reap the medical benefits.
Lottie Peppers

Ancient Viruses Gain New Functions in the Brain - Scientific American - 0 views

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    If thinking about the billions of bacteria taking up residence in and on your body gives you the willies, you probably won't find it comforting that humans are also full of viruses. These maligned microbes are actually intertwined in the very fibers of our being-about 8 percent of our genetic material is made up of absorbed forms of retroviruses, the viral family to which HIV, the pathogen that causes AIDS, belongs.
Lottie Peppers

Agriculture Linked to DNA Changes in Ancient Europe - NYTimes.com - 0 views

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    The agricultural revolution was one of the most profound events in human history, leading to the rise of modern civilization. Now, in the first study of its kind, an international team of scientists has found that after agriculture arrived in Europe 8,500 years ago, people's DNA underwent widespread changes, altering their height, digestion, immune system and skin color. Researchers had found indirect clues of some of these alterations by studying the genomes of living Europeans. But the new study, they said, makes it possible to see the changes as they occurred over thousands of years.
Lottie Peppers

The History Of Scientific Classification - 0 views

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    Early classification systems probably grouped organisms as to whether they were beneficial or harmful. Another ancient classification system recognized 5 animal groups - domestic animals, wild animals, creeping animals, flying animals, and sea animals.
Lottie Peppers

Do You See What Eye See? - National Center for Case Study Teaching in Science - 0 views

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    A common misconception is that Darwin suggested that something as complex as the eye could not have evolved through natural selection. While the misunderstanding often comes from an incomplete reading of his argument, we have long known that intermediate varieties of eyes (e.g., eyespots, cupped eyes, and complex camera-type eyes) exist in a variety of organisms. Eyes are so common that it was thought that they had evolved independently 40-60 times. More recent molecular work, however, has identified the role of Pax6 genes and their homologs in the formation of eyes during development. The basic information for eye formation appears to have been present in the common ancestor to all bilaterans, and perhaps may be more ancient than that. This interrupted case study examines the history of evidence for eye evolution from Darwin's initial postulates, through evidence of multiple intermediate forms, concluding in an examination of Pax6 homologs. The case is primarily for an introductory biology class but an additional section would be appropriate for upper-level evolution or developmental biology courses.
Lottie Peppers

DNA from 4,500-year-old Ethiopian reveals surprise about ancestry of Africans - LA Times - 0 views

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    DNA from a man who lived in Ethiopia about 4,500 years ago is prompting scientists to rethink the history of human migration in Africa. Until now, the conventional wisdom had been that the first groups of modern humans left Africa roughly 70,000 years ago, stopping in the Middle East en route to Europe, Asia and beyond. Then about 3,000 years ago, a group of farmers from the Middle East and present-day Turkey came back to the Horn of Africa (probably bringing crops like wheat, barley and lentils with them).
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