Today, however, with global warming, climate change is happening much faster than it has in the past some species may not be able to adapt quickly enough and may face extinction. One thing they caution is that these natural adaptations took place due to the climate over long periods of time. Through past glacial and interglacial episodes, they were able to detect adaptations in certain species, such as voles. One of the interesting conclusions they made is that of species evolution and adaptation. A major climate change that took place 800,000 years ago was identified. In their studies, they have analyzed environmental conditions of the area over a large span of time and have identified evidence of climate changes, such as glacial and interglacial events. So, climate changes like the global warming we are seeing today are probably happening too fast to cause anything but extinction." It takes a long time for a species to change, and even the major climatic change 800,000 years ago wasn't dramatic enough to cause the origin of a new species."īased on his studies, Barnosky concludes, "It's likely that specia-tion takes place over a longer time interval than extinction. Our study suggests that species adapt to handle routine climate change, and only something out of the ordinary initiates significant evolutionary change. This is the first study where we've actually taken a living species and looked back almost a million years at the population level to see how it changes through time. According to Tony Barnosky, "Everything in the cave has been nicely preserved at a controlled temperature and humidity, like putting the stuff in a refrigerator for 750,000 years. Due to the arid cave's controlled temperature and humidity, the specimens were well preserved. Spaulding, photographer)Īn associate professor of geology at the University of Texas at Austin- discovered a pack rat collection of teeth and bones that dates back to between 600,000 and 1 million years ago. (NOAA Paleoclimatology Paleo Slide Set W.G. It was not until the 1960s that paleoecologists realized that middens could be used as a tool to reconstruct past climatic conditions. (NOAA Paleoclimatology Paleo Slide Set Ken Cole, USGS, photographer) Paul Martin of the University of Arizona is examining a pack rat midden. The plant remains and other debris become cemented into large masses of crystallized urine that can survive for tens of thousands of years and be used as climate proxies. They gather plant materials at close range and accumulate them in dry caves and crevices. Pack rats are roughly the size of laboratory rats. In a cave in Colorado, other researchers- Tony Barnosky, a paleo -biologist from the University of California, Berkeley, and Chris J. To date, the USGS has been involved in pack rat midden and climate change studies in Arizona, California, Colorado, and Utah. According to the USGS, radiocarbon dating has identified some middens that are more than 50,000 years old.īecause these samples are useful so far back in time, their analysis has become important for reconstructing biotic communities and envi ronmental conditions. Scientists derive this data through analysis of the ratios of stable isotopes of oxygen, carbon, and deuterium. Information about past atmospheric conditions is also contained in the middens. These findings help reconstruct the past environment, illustrating what the climate conditions were at the time. Fossil pack rat (also known as wood rat) middens (crystallized urine) often con -tain abundant fossilized remains of leaves, twigs, fruits, seeds, bones, shells, and other dateable materials. Geological Survey (USGS) is currently involved in research along these lines in the southwestern United States. Another proxy method that scientists use to reconstruct past periods of climate change is through analysis of plant remains from fossil pack rat middens.
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