Archaeology News Online

Today mammals and birds are the only true warm-blooded animals. They are called endotherms, meaning they produce their body heat internally. The skeleton of a therapsid dicynodont Lystrosaurus [Credit: Flickr] Endotherm animals are the opposite to ectotherms which get their heat from an external factor like the sun. They are considered “cold-blooded”. The origins of warm-bloodedness in mammals has been a very controversial issue for two reasons. One is that several of the anatomical features thought to be linked to warm-bloodedness have also been found in cold-blooded reptiles. The other is that these characteristics are not always preserved in fossils, giving scientists inconsistent signals about the presence of warm-bloodedness. Our research helps shed new light on this controversy. We’ve been able to come up with new insights about how mammals developed a warm-blooded metabolism that may have helped them survive the terrible mass extinction that marked the end of the Permian period...

New biological information gleaned from the red vizcacha rat, a native species of Argentina, demonstrates how genomes can rapidly change in size. Red vizcacha rat, a rare species found in Argentina [Credit: McMaster University] Researchers from McMaster University set out to study this particular species because its genome, or its complete set of DNA, is the largest of all mammals, and appears to have increased in size very rapidly. The rat's genome is roughly two-and-a-half times as large as the human genome, including 102 chromosomes versus 46 for humans, and is about twice as large as one of its closest relatives, the mountain vizcacha rat. The most recent common ancestor of these species existed only about five million years ago. "This genomic transformation is striking because it happened over a very short period of time in evolutionary terms," says Ben Evans, a biologist at McMaster and lead author of the new research published in the journal Genome Biology and Evol...

A new study involving The University of Queensland, which might be useful for biomedical research, re-writes parts of the rulebook on how mammalian brains -- including our own -- could have evolved. Chart of 3D-reconstructed dissected brains and, where available, head outlines used in this study. Green/light red,  the two olfactory bulbs; orange/blue, cerebral hemispheres; dark green, midbrain; yellow, cerebellum;  cherry red, medulla [Credit: Dr. Vera Weisbecker] It includes the possibility that distinctive dominance of our own cerebral hemispheres is not, as previously suggested, just a side-effect that forces brains of a particular size to have particular proportions. Dr Vera Weisbecker of UQ's School of Biological Sciences said the study represented the first dataset comparing brain growth in different mammals, gathered through a novel method of non-invasive micro-CT (computed tomography) scanning which allowed the fast data acquisition of soft tissue growth in tiny mammal...

Today mammals and birds are the only true warm-blooded animals. They are called endotherms, meaning they produce their body heat internally. The skeleton of a therapsid dicynodont Lystrosaurus [Credit: Flickr] Endotherm animals are the opposite to ectotherms which get their heat from an external factor like the sun. They are considered “cold-blooded”. The origins of warm-bloodedness in mammals has been a very controversial issue for two reasons. One is that several of the anatomical features thought to be linked to warm-bloodedness have also been found in cold-blooded reptiles. The other is that these characteristics are not always preserved in fossils, giving scientists inconsistent signals about the presence of warm-bloodedness. Our research helps shed new light on this controversy. We’ve been able to come up with new insights about how mammals developed a warm-blooded metabolism that may have helped them survive the terrible mass extinction that marked the end of the Per...

New biological information gleaned from the red vizcacha rat, a native species of Argentina, demonstrates how genomes can rapidly change in size. Red vizcacha rat, a rare species found in Argentina [Credit: McMaster University] Researchers from McMaster University set out to study this particular species because its genome, or its complete set of DNA, is the largest of all mammals, and appears to have increased in size very rapidly. The rat's genome is roughly two-and-a-half times as large as the human genome, including 102 chromosomes versus 46 for humans, and is about twice as large as one of its closest relatives, the mountain vizcacha rat. The most recent common ancestor of these species existed only about five million years ago. "This genomic transformation is striking because it happened over a very short period of time in evolutionary terms," says Ben Evans, a biologist at McMaster and lead author of the new research published in the journal Genome Biology and Evol...