Sentences with phrase «of early mammal»

This was strong evidence that Haramiyavia was unrelated to other crown mammals — in particular, the multituberculates, a group of early mammal that has previously been thought to be closely related to the haramiyids.

Before the dinosaurs, around 260 million years ago, a group of early mammal relatives called dicynodonts were the most abundant vertebrate land animals.

Trying to resolve that question, Rich Cifelli of the Oklahoma Museum of Natural History in Norman and two colleagues ran a computer comparison of early mammal teeth and jaws.

The old hypothesis hinged upon the fact that many of the early mammal fossils that had been found were from small, insect - eating animals — there didn't seem to be much in the way of diversity.

«In terms of what we know about the evolution of early mammals, Rich's is the most parsimonious interpretation,» he says.

And Krause notes, «Both of these discoveries together underscore to me that we really do need to keep an open mind about the biogeography of early mammals on Gondwana.»

That scenario upends a long - standing theory about where some of the earliest mammals originated and how they colonized the world.

By holding their limbs directly beneath their bodies, the argument went, dinosaurs would have moved faster and more efficiently than the cousins of crocodiles and relatives of early mammals that also lived at the time.

Snakes were «the first and most persistent predators» of early mammals, says Lynne Isbell, a behavioral ecologist the University of California, Davis.

That picture has begun to change, however, with the discovery of a number of early mammals that were well adapted to a variety of ecological niches, including eating plants that huge vegetarian dinosaurs also munched on.

Lead author, Dr Pamela Gill of the University of Bristol, said: «None of the fossils of the earliest mammals have the sort of exceptional preservation that includes stomach contents to infer diet, so instead we used a range of new techniques which we applied to our fossil finds of broken jaws and isolated teeth.

I want to give you an overview of the earliest mammals: mammals from the time of the dinosaurs.

Not exact matches

Most remarkably, the creature, which was less than 3 feet long, had the body of a fish but the jaws, ribs, and limb - like fins seen in the earliest land mammals.»

The early mammals lived in the interstices of the dinosaurs» world.

It includes the Stromatolites from the Precambrian (colonies of prokaryotic bacteria), the Ediacara fossils from South Australia, the Cambrian species of the Burgess shale (circa — 450 million years) the giant insects of the Devonian period, the many precursors to the dinosaurs, the dinosaurs themselves, the subsequent dominant mammals, including the Saber Tooth Tiger, the Mammoths, the fossils of early man in Africa, the Neanderthals of Europe.

The fossil record includes the Stromatolites, colonies of prokaryotic bacteria, that range in age going back to about 3 billion years, the Ediacara fossils from South Australia, widely regarded as among the earliest multi-celled organisms, the Cambrian species of the Burgess shale in Canada (circa — 450 million years ago) the giant scorpions of the Silurian Period, the giant, wingless insects of the Devonian period, the insects, amphibians, reptiles, fishes, clams, crustaceans of the Carboniferous Period, the many precursors to the dinosaurs, the 700 odd known species of dinosaurs themselves, the subsequent dominant mammals, including the saber tooth tiger, the mammoths and hairy rhinoceros of North America and Asia, the fossils of early man in Africa and the Neanderthals of Europe.

Meconium is the earliest stool of an infant mammal.

We can not use randomized controlled experiments with people but do so with animals, demonstrating, for example in Michael Meaney's lab, that affectionate touch in early life is critical for epigenetic controls of anxiety in mammals.

DR. STACEY MERLO: They are important for birth because human babies have the biggest head of almost any mammal that gets passed through and we're actually delivering babies earlier than their full term development because of the size of the head and all of us have had babies in the room and we know that that's the hardest part.

Learn about the birth and early stages of development of 14 different mammals, including the hooded seal, the pacific gray whale, the polar bear, and the human.

Homo sapiens, Neanderthals and other recent human relatives may have begun hunting large mammal species down to size — by way of extinction — at least 90,000 years earlier than previously thought, says a new study published in the journal Science.

He adds that many groups of mammals that live on the mainland today were not present during the early phases of colonization of Madagascar, limiting potential migrant diversity.

Warmer winters, wetter and earlier springs (which expand the time during which ticks can pick up the disease), increased humidity, and greener environments can all contribute to the increased incidence of ticks and the growing populations of hosts, including large mammals like white - tailed deer; smaller ones such as white - footed mice, the principal carrier of Lyme disease; and many species of birds.

The researchers discovered that both major living lineages of birds (the common neognaths and the rarer paleognaths) differ from the major lineages of non-bird reptiles (crocodiles, turtles, and lizards) and from mammals in having a unique, median gene expression zone of two different facial development genes early in embryonic development.

From measuring the number of character changes over time for each branch, they found the average rate of evolution for early placental mammals both before and after the dinosaur extinction event.

To figure out how chromosomes of placental mammals have changed over time, researchers need to know what those early eutherians started with.

The original importer had brought in, weeks earlier, a shipment of about 800 small mammals from Ghana, including the rodents, the known reservoir for monkeypox.

The origins of imprinting probably date back about 150 million years to early mammals.

Although the bulk of the commercial manufacturing uses cultures of bacteria, such as Escherichia coli or Chinese hamster ovary cells, a few biotech companies are trying to produce therapeutic proteins in the milk of transgenic mammals (such as GTC Biotherapeutics, which is using goats; PPL Therapeutics, which is using sheep; and BioProtein Technologies, which is working with rabbits), transgenic chicken eggs (such as Avigenics or Vivalis), or even in transgenic crops (such as ProdiGene or Meristem Therapeutics); but it is early days for these «pharming» methods.

Above this, in sediments 2.5 million years old, are traces of the butchery of large mammals accompanied by some of the earliest stone tools.

Earth's climate was transitioning from greenhouse to icehouse, and the ancestors of modern reptiles and mammals (as well as the precursors of dinosaurs) had begun to emerge from earlier large amphibians.

Dr. Paul Barrett, dinosaur researcher at the Natural History Museum, London, who was not involved with the study, commented, «Daohugou is proving to be one of the key sites for understanding the evolution of feathered dinosaurs, early mammals, and flying reptiles, due largely to the fantastic levels of preservation.

Despite the fact that X is much larger than the tiny Y, it seems that both evolved from a pair of conventional chromosomes in early mammals sometime in the past 300 million years — an idea first proposed in 1967.

At the annual meeting of the Ecological Society of America held here earlier this week, a researcher offered intriguing evidence suggesting that chilies wield their sting with the precision of a stiletto: to target seed - chewing mammals while leaving birds unscathed.

Nicholas Pyenson, curator of fossil marine mammals at the Smithsonian Institution, reached a similar conclusion after analyzing earlier gray whale fossils from the Pleistocene.

«It documents that transition from the early mammals we see after the extinction of the dinosaurs to Eocene mammals, which are in groups that are familiar today.

Earlier studies demonstrated that mammals and birds move to avoid areas of snowmobile use and that their heart rates increase in the presence of the machines.

The Daohugou Biota makes an immense contribution to our understanding of vertebrate evolution during this period, with such notable creatures as the oldest known gliding mammal, another early mammal that may have swum with a beaver - like tail, the oldest dinosaurs preserved with feathers, and a pterosaur that represents an important transitional form between two major groups.

Earlier studies have shown that cannabis production causes environmental damage, including rodenticide poisoning of forest mammals and dewatering of streams due to improper irrigation.

Over the last two decades, huge numbers of fossils have been collected from the western Liaoning Province and adjacent parts of northeastern China, including exceptionally preserved feathered dinosaurs, early birds, and mammals.

If there were placental mammals in the Early Cretaceous of Australia, Krause says, it would «push back the record of placentals farther than we expected on any southern land mass and in many ways revolutionize our concept of early mammalian biogeography.&rEarly Cretaceous of Australia, Krause says, it would «push back the record of placentals farther than we expected on any southern land mass and in many ways revolutionize our concept of early mammalian biogeography.&rearly mammalian biogeography.»

Because so little is known about Gondwanan mammals, Krause is wary of dismissing Rich's interpretation «just because we don't expect, based on current knowledge of early mammalian evolution on Gondwana, to see a placental mammal in the Early Cretaceous of Australia.&rearly mammalian evolution on Gondwana, to see a placental mammal in the Early Cretaceous of Australia.&rEarly Cretaceous of Australia.»

The researchers» conclusion that terrestrial placental mammals may have lived down under 110 million years earlier than expected, as reported in the November 21, 1997 issue of Science, could all but uproot the mammalian family tree.

Did the earliest ancestors of swimming mammals fumble as they took to the water?

This mix of genes, he says, supports the classification of the platypus as a unique and very early mammal.

A fossil jawbone from an early Australian mammal proves that the hearing of at least two different groups of mammals developed independently in almost exactly the same way.

The diversity of native species hinted that the island's ecosystem had weathered the mammal introduction, but there were no detailed historical records to compare with, says Ostendorf, who presented the work at the Natural Resource Management Science Conference in Adelaide earlier this month.

Early paleontological sites in the Bahamas have yielded bones from numerous species of reptiles, birds and mammals that no longer exist on the islands.

So it's possible that these early relatives of modern mammals evolved in cooler, upland areas and that the dinosaurs were in the hotter, lowland areas.

Thus, «giant chunks of space debris clobbering the planet and wiping out life on Earth has undeniably broad appeal,» Meltzer says, whereas «no one in Hollywood makes movies» about more nuanced explanations, such as Clovis points disappearing because early Americans turned to other forms of stone tool technology as the large mammals they were hunting went extinct as a result of the changing climate or hunting pressure.