![]() Obtaining observations of giant stars which typically dwell in the densely populated hearts of dust-shrouded star clusters is particularly challenging. The image challenges our understanding of the most massive stars.Īstronomers have yet to fully understand how the most massive stars - those more than 100 times the mass of the Sun - are formed. Scientists have obtained the sharpest image ever of the most massive known star in the universe using the 8.1-meter Gemini South telescope in Chile. Sharpest image of most massive known star Researchers say that natural selection led to the evolution of jaws, facial muscles, and teeth that make the chewing system as efficient as possible, thus minimising the energy spent chewing food. ![]() And since our ancestors didn’t cook as we do now, they would have needed more energy to chew their food.įood was a scarce commodity for early humans, which made it important from an evolutionary perspective to minimise the energy spent consuming these limited resources. The “simple” process of chewing food may have played a crucial role in the evolution of our jaws, facial muscles and teeth, a new peer-reviewed study published in the journal Science Advances has found.Īccording to researchers from Leiden University in The Netherlands, this is the first attempt ever to measure the energy cost of human chewing.įor the study, researchers used a device that measured movements to calculate energy spent while 15 women and six men aged between 18 and 45 were made to chew two different types of tasteless gum: soft and stiff.Ī special hood was used to measure the volunteers’ oxygen consumption and carbon dioxide production, and electrodes were used to measure the activity of their masseter muscles.Īccording to the team, chewing softer gum increased energetic expenditure - amount of energy needed to maintain essential body functions - by an average of 10.2 per cent, while the same for chewing stiffer gum was 15.1 per cent.Ĭompared to most modern foods which are processed and relatively soft, the foods consumed by early humans, such as seeds, nuts, tubers and fibrous leaves, would have been much tougher. Īlso Read: New dinosaur species ‘Jakapil kaniukura’ weighing just 4-7 kg discovered in Argentina south ![]() Researchers, as part of the study, laid out vast anatomical changes that took place in many reptile groups, including the forerunners of crocodiles and dinosaurs, in direct response to major climate shifts concentrated between 260 to 230 million years ago. However, the team has now found that the physical evolution and diversification seen in early reptiles not only started years before these mass extinction events but instead were directly driven by what caused them in the first place - rising global temperatures due to climate change. New Delhi: Rising global temperatures just over 250 million years ago caused the rates of evolution and diversity of reptiles to explode, giving way to a variety of acquired abilities, physical characteristics and traits, a peer-reviewed study published in the journal Nature Communications study has found.Īccording to the study, led by scientists from Harvard University in the US, this extreme climate shift just over 250 million years ago helped establish reptile lineages as one of the most successful and diverse animal groups in the world.Įarlier, researchers had thought that this explosion in reptile species was the result of two of the biggest mass extinction events that wiped out competition, around 261 and 252 million years ago. ![]()
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