Wings, tails, fins: Study looks at how animals propel themselves

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The wonder of animal movement — from the tiniest of insects to the largest fish in the sea — has been a subject of mystery for ages. But when it comes to animal propulsion, there are almost infinite kinds, but also limits that can’t be pushed or breakdowns will occur, according to an unusual study from a team that includes a Texas A&M University at Galveston researcher.Nathan Johnson, a graduate student at Texas A&M-Galveston who also teaches in the marine biology department, and colleagues from Harvard, California Institute of Technology, Indiana University and the Woods Hole Oceanographic Institute have studied the complex ways animal movements have evolved over millions of years and through hundreds of species. Their findings have been published in the current issue of Nature Communications.The team narrowed animal subjects down to 59 species for the study, and concentrated on ways each one is able to propel itself — through air, land or water.The key word appears to be “bend.” One common trait they found was each creature being able to “bend” its means of propulsion, but only to a certain point.”If you take the wing of a bird or a bat, or the fins on a fish or a manta ray, you find that their means of propulsion are flexible,” Johnson explains. “They can move back or forth or sideways easily, or they bend. But this bending and flexibility will only go so far, and it can’t bend any more.”For example, the fixed wing on an airplane is not flexible, while nature has had millions of years to figure out the best way to do it better than we can. So we wanted to see if there any patterns to this flexibility.”For most creatures, there is a certain angle that these propulsion devices will reach and won’t exceed. It’s not that they probably can’t exceed these angles, but rather doing so is just not energetically efficient for them.”There does seem to be a universal range of movement in the species we looked at, from the fruit fly to the humpback whale.”The team found that a 30 to 60-degree angle seems to be the magic range of how far animal propulsion can bend. “This appears to be especially true with bird wings, while insect wings typically bend slightly less than other organisms we looked at,” Johnson adds.Also, the researchers agreed that environmental factors could be a factor in the range of movement. And some species move almost identically to vastly different species; they found that much of the motion made by marine life is almost identical to that of birds — that is, the fin of a fish moves just like the wing of a bird.”We need to understand a lot of these motion patterns in much more detail,” Johnson says.”There are some current day tests being done with man-made materials to see if they can duplicate animal motion, such as some being done with jellyfish. The more we learn about animal propulsion and the way it’s been developed over millions of years of evolution, the more it can help us with human engineering and how we can improve our own movement.”The project was funded by the National Science Foundation.Story Source:The above story is based on materials provided by Texas A&M University. …


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#Agriculture, #Alzheimer, #Animal, #California, #Galveston, #Health, #Study, #University

Cities support more native biodiversity than previously thought

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The rapid conversion of natural lands to cement-dominated urban centers is causing great losses in biodiversity. Yet, according to a new study involving 147 cities worldwide, surprisingly high numbers of plant and animal species persist and even flourish in urban environments — to the tune of hundreds of bird species and thousands of plant species in a single city.Contrary to conventional wisdom that cities are a wasteland for biodiversity, the study found that while a few species — such as pigeons and annual meadow grass — are shared across cities, overall the mix of species in cities reflects the unique biotic heritage of their geographic location. The findings of the study conducted by a working group at UC Santa Barbara’s National Center for Ecological Analysis and Synthesis (NCEAS) and funded by the National Science Foundation were published today in the Proceedings B, a journal of the Royal Society of Biological Sciences.”While urbanization has caused cities to lose large numbers of plants and animals, the good news is that cities still retain endemic native species, which opens the door for new policies on regional and global biodiversity conservation,” said lead author and NCEAS working group member Myla F. J. Aronson, a research scientist in the Department of Ecology, Evolution and Natural Resources at Rutgers, The State University of New Jersey.The study highlights the value of green space in cities, which have become important refuges for native species and migrating wildlife. This phenomenon has been named the Central Park Effect because of the surprisingly large number of species found in New York’s Central Park, a relatively small island of green within a metropolis.Unlike previous urban biodiversity research, this study looks beyond the local impacts of urbanization and considers overall impacts on global biodiversity. The research team created the largest global dataset to date of two diverse taxa in cities: birds (54 cities) and plants (110 cities).Findings show that many plant and animal species, including threatened and endangered species, can flourish in cities, even as others decline or disappear entirely. Cities with more natural habitats support more bird and plant species and experience less loss in species as the city grows. Overall, cities supported far fewer species (about 92 percent less for birds and 75 percent less for native plants) than expected for similar areas of undeveloped land.”We do pay a steep price in biodiversity as urbanization expands,” said coauthor Frank La Sorte, a research associate at the Cornell Lab of Ornithology. “But even though areas that have been urbanized have far fewer species, we found that those areas retain a unique regional flavor. …


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#Animal, #Centralpark, #Ecology, #Jersey, #Losses, #Major, #Nceas, #Pregnancy, #Science

Giant mass extinction quicker than previously thought: End-Permian extinction happened in 60,000 years

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The largest mass extinction in the history of animal life occurred some 252 million years ago, wiping out more than 96 percent of marine species and 70 percent of life on land — including the largest insects known to have inhabited Earth. Multiple theories have aimed to explain the cause of what’s now known as the end-Permian extinction, including an asteroid impact, massive volcanic eruptions, or a cataclysmic cascade of environmental events. But pinpointing the cause of the extinction requires better measurements of how long the extinction period lasted.Now researchers at MIT have determined that the end-Permian extinction occurred over 60,000 years, give or take 48,000 years — practically instantaneous, from a geologic perspective. The new timescale is based on more precise dating techniques, and indicates that the most severe extinction in history may have happened more than 10 times faster than scientists had previously thought.”We’ve got the extinction nailed in absolute time and duration,” says Sam Bowring, the Robert R. Shrock Professor of Earth and Planetary Sciences at MIT. “How do you kill 96 percent of everything that lived in the oceans in tens of thousands of years? It could be that an exceptional extinction requires an exceptional explanation.”In addition to establishing the extinction’s duration, Bowring, graduate student Seth Burgess, and a colleague from the Nanjing Institute of Geology and Paleontology also found that, 10,000 years before the die-off, the oceans experienced a pulse of light carbon, which likely reflects a massive addition of carbon dioxide to the atmosphere. This dramatic change may have led to widespread ocean acidification and increased sea temperatures by 10 degrees Celsius or more, killing the majority of sea life.But what originally triggered the spike in carbon dioxide? The leading theory among geologists and paleontologists has to do with widespread, long-lasting volcanic eruptions from the Siberian Traps, a region of Russia whose steplike hills are a result of repeated eruptions of magma. To determine whether eruptions from the Siberian Traps triggered a massive increase in oceanic carbon dioxide, Burgess and Bowring are using similar dating techniques to establish a timescale for the Permian period’s volcanic eruptions that are estimated to have covered over five million cubic kilometers.”It is clear that whatever triggered extinction must have acted very quickly,” says Burgess, the lead author of a paper that reports the results in this week’s Proceedings of the National Academy of Sciences, “fast enough to destabilize the biosphere before the majority of plant and animal life had time to adapt in an effort to survive.”Pinning dates on an extinctionIn 2006, Bowring and his students made a trip to Meishan, China, a region whose rock formations bear evidence of the end-Permian extinction; geochronologists and paleontologists have flocked to the area to look for clues in its layers of sedimentary rock. …


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#Alternative-Medicine, #Animal, #China, #Marine, #Permian, #Science, #Species, #Traps