As the evolution of the earth in dinosaurs, one of the most dramatic changes in the history of life was the evolution of whales: rows of flexible hair such as hair, blue whale, diving and other mammals use sea-water to filter gulps. An unusual structure, the abundant creature in the world consumes tons of food every day, never slicing or munching. Now, Smithsonian scientists have found an important media link in the evolution of this innovative nutritional strategy: they did not have an old whale or whale.
It was published on the 29th of the magazine Current biologyThe Smithsonian Natural History Museum and colleagues describe scientists for the first time Maiabalaena nesbittaeThe whale lived around 33 million years ago. Using the new methods found in fossils found in the Smithsonian National Collection, researchers from the Burke Museum of Natural History and Culture at the University of Texas A & M and Seattle, Seattle, studied teeth whitening 15 Whale Whale There were no whales, they show the amazing whale of whales that live today and the whales between their ancestors.
"When we talk about the evolution of the bee, textbooks are angry at the beginning, when whales pass through the sea to the ground," said National Mammalian mammals commissioner at the National Natural History Museum. "Maiabalaena The second phase of the whale's evolution is very important in terms of the evolution of large scale ones. For the first time, we now announce the origin of filter feed, which is one of the most important innovations in the history of whale. "
When whales evolved for the first time, they drank their teeth, like those of the earth. As time passed, morning whales many of these descendants continued to chew food, distinguished from the previous one. But the oceans around them changed and the animals evolved, new nutrition strategies emerged, including the feeding of whales filters, says National Museum of Natural History before Dr. Carlos Mauricio Peredo. Maiabalaena fossils
Whales were the first mammals of the whale's evolution, and other mammals do not use any anatomical structure, although they are remotely consuming similar predators. But frustratingly, whales, whose chemical composition is like hair or nails rather than bone, does not keep well. It is rarely found in the fossil record, leaving the paleontologist without proof of its past or origin. Instead, scientists carry out examinations of fossil and fetal whales in their stomachs and collect traces of whales.
As a result, it is not clear or not, as they are evolving, at the beginning of the whale's whale the ancestors' teeth were maintained until a filtering system was maintained. At the beginning presupposition, Peredo said that mammals in ocean homes should eat their teeth or whales, but some whales live to contradict this idea. Sperm whales have teeth on the bottom jaw, but not at the top, so they can not bite or chew. The only teeth of Narwhals are their long tusks, and they do not use them to feed. And if there are some species that are wholly made up, they have no such thing.
Peredo said that paleontologists suspected Maiabalaena It can contain important traces of whale evolution. Fossil is a time of massive geological change. During the second major phase of the evolution of the whale, the time of Eocene occurred at the time of the Oligocene. With the outward and separating continents, ocean currents hanged around the Antarctic for the first time, with water cooling dramatically. The fossil record indicates that whale feeder styles have rapidly disappeared over time over time, a group that leads to the current filtering feeder whale and the other ecolocation.
As a result, Maiabalaena In the 1970s, he received a lot of research in Oregon, but the fossil matrix and fossil material still had many features hidden. Until then, Peredo opted for the fossil clearing of CT technology with advanced technology. MaiabalaenaThe lack of the tooth defects in the bone was clear, but the CT analysis revealing the anatomy of the fossils, scientists said something new: MaiabalaenaThe upper thigh was thin and narrow, with a poor surface and dropping the emptiness of whales.
"The baleen whale of life has a large, wide roof in the mouth, and it also thickens the whale attachments," said Peredo. "Maiabalaena It does not. However, we can say that this fossil species did not say the teeth, and it might not be whales either. "
Meanwhile Maiabalaena It would not be possible to filter the feeders or filters, the muscles of the throat in the bones would indicate a powerful and painful retina. These characteristics could be absorbed with water in the mouth, taking fish and squid in the process. The suction feed ability should render their teeth, which requires a lot of energy-intensive development, useless. Therefore, the loss of the teeth caused a whale-stroke evolution, and scientists estimated 5 million and 7 million years later.
Peredo and Pyenson explore the evolution of whales to understand survival in today's fast-moving oceans. As the baleen generation suggests, the loss of whales due to mold-making evidence suggests that whale may be capable of adapting to today's ocean challenges. However, Peredo explains that evolutionary changes can be slow, because they can be large, have a long life and play for a long time.
"Given the current scale and rate of ocean change, we do not know exactly what they mean for all kinds of filter feeders," he said. "We know that we know about changes in the past, we are changing the ocean or any obstacle we are doing quite quickly."
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