All Stages From Life To Death
Taken on the grounds of the Gilcrease Museum in Tulsa, Oklahoma.
I thought it was very cool how this one leaf displays all of the stages from life to death.
Via Flicker.........
Posted by: Jessica Permalink Source
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Taken on the grounds of the Gilcrease Museum in Tulsa, Oklahoma. I thought it was very cool how this one leaf displays all of the stages from life to death. Via Flicker......... Posted by: Jessica Permalink Source Myths about species abundance
"When we evaluated data from published studies that looked at species abundance at multiple sites across a range, we found almost no evidence that supported the so-called 'abundant-center hypothesis' and good evidence that contradicted it," said Raphael D. Sagarin, associate director for oceans and coastal policy at Duke University's Nicholas Institute for Environmental Policy Solutions. "This is troubling," Sagarin said, "because a lot of current thinking on ecological and evolutionary issues -- including how species will respond to climate change, how to identify probable locations of pest outbreaks, how genetic diversity is distributed among populations and where to locate habitat preserves -- has been based on the hypothesis". The validity of these ideas now needs to be re-examined using empirical studies, he said. Sagarin is one of the principal authors of the report, which appeared in the September 2006 issue of the journal Trends in Ecology and Evolution. Other authors are Steven D. Gaines of the University of California-Santa Barbara's Marine Science Institute and Department of Ecology, Evolution and Marine Biology; and Brian Gaylord of the University of California-Davis's Bodega Marine Laboratory and Section of Evolution and Ecology......... Posted by: Ashley Permalink Source Reintroducing Megafauna To North America
A massive Ecological History Park of North America with free-roaming elephants, lions and other large animals that went extinct 13,000 years ago in North America.
Credit: Illustration by Carl Buell In the recent issue of The American Naturalist, a group of 12 ecologists and conservationists provide a detailed proposal for the restoration of North America's lost megafauna. Using the same species from different locales or closely related species as analogs, their project "Pleistocene Rewilding" is conceived as carefully managed experiments in an attempt to learn about and partially restore important natural processes to North American ecosystems that were present for millennia until humans played a significant role in their demise 13,000 years ago. "Over the past 30 years, more and more evidence suggests that if we lose large animals from ecosystems, they often collapse and biodiversity, along with society, are the ultimate losers," says Josh Donlan (Cornell University). "For millions of years, large animals were the norm all over the world we should start thinking about reintroducing these large animals and restoring these important processes back to ecosystems"......... Posted by: Ashley Permalink Source Big Welcome For A Big Cat
©WCS/J.Maher
Click here to read more about the expedition and diplomatic collaboration that led to Leo's relocation. First lady of Pakistan Sebha Musharraf was among the honored guests to officially welcome Leo. "Wildlife is among our greatest resources," she said. "It provides both beauty and a discovery of the natural world around us. Leo is a most fitting wildlife ambassador, representing both Pakistan and his species. It is our hope that he will inspire others to care". Assistant Secretary of State for Oceans, Environment and Science Claudia A. McMurray also attended the welcome ceremony. She commented, "Today we celebrate the arrival of this beautiful snow leopard cub as a symbol of hope for the global effort to save endangered wildlife. I am especially pleased that diplomacy between the United States and Pakistan played a key role in making this accomplishment possible". The 14-month-old male cub will remain at the Bronx Zoo until an appropriate facility can be constructed in Pakistan. As a world leader in snow leopard care-and the first zoo in the Western Hemisphere to exhibit these big cats, in 1903-the Bronx Zoo will provide a secure refuge for the growing cub......... Posted by: Ashley Permalink Source Hearts Or Tails?
Image courtesy of Harvard University
Brad Davidson and his colleagues in Michael Levine's lab at UC Berkeley have discovered that the transcription factor Ets1/2, along with the signaling molecule FGF, controls early heart formation in the sea squirt, Ciona intestinalis. Sea squirts are most usually found in shallow ocean waters attached to algae, rocks or seaweed. They have been used for over 100 years as a highly useful experimental model organism for the study of animal development. A simple chordate, Ciona is being used in the lab to study the heart development of higher organisms because it shares several characteristics with vertebrates - eventhough ultimately, Ciona, develops a heart with just one chamber (as opposed to vertebrates' multi-chambered heart). All of the cells that form the Ciona heart are originally derived from two early embryonic cells (called bastomeres). These cells divide into separate lineages: the smaller rostral cells become heart muscle, while the larger caudal cells become tail muscle. Davidson and his colleagues observed that Ets1/2 underlies the cells' decision to become either heart or tail. When activated, Ets1/2 instructs cells to form heart muscle......... Posted by: Ashley Permalink Source Polar Bear Habitat Preferences
Polar bear habitat preferences and prey availability in a changing sea ice environment. In the Beaufort Sea, polar bears (Ursus maritimus), ringed seals (Phoca hispida), and bearded seals (Eriginathus barbatus), inhabit a seasonably dynamic environment that has experienced climate-induced changes. During most seasons polar bears prefer mixed ice habitats near ice edges in shallow waters over the continental shelf. In past decades, polar bears could maintain this habitat preference for nearshore ice, but in recent years, extensive ice melt has forced most polar bears to summer in deepwater ice habitat more than 200 km from the mainland coast. A smaller segment of the population is forced to use shoreline habitat. Other research suggests that prey resources may be diminished for polar bears force to occupy land and the deep water pack ice during summer. For example, the winter and spring distribution of ringed seals, the most important prey for polar bears, reflects the general distribution of polar bears. During summer, while some ringed seals may track the ice edge as it retreats north, others may have an open water life style and thus would be unavailable to polar bears. Bearded seals, due to their bottom-feeding habits, have not been available to polar bears summering over deep-water habitats during recent summers. In addition, a changing sea ice environment may affect reproduction of both predator and prey. A number of pregnant polar bears in Alaska den on the active sea ice, the thinning of which brings into question whether winter ice has the stability necessary for successful denning. Seals also depend on sea ice for birth and hence are also susceptible to changes in the composition of sea ice. George Durner and Steven Amstrup, Session 33, Tuesday, Sept. 26, 8:40-9:00 a.m......... Posted by: Ashley Permalink Source Groundbreaking Study By On Lions Mane Variability
According to the overall findings of the study, wild lions generally develop manes in accordance with local climate regimes. In Equatorial east Africa, climate is determined by elevation. Thus lions with the most profuse manes occur at the upper limit of their altitudinal range, while similar aged males in the lowest and warmest environments like Tsavo typically carry only modest or scanty manes. However, the authors also found, paradoxically, that the majority of lions in regions like the greater Tsavo ecosystem (which is famed for its "maneless" lions), did appear to acquire respectable manes, eventually, contrary to most recent popular and scientific accounts of the lions from that region. "We knew about the climate/elevation correlation since we were the first to publish those preliminary results in GEO 2001, but this new development really threw us for a loop," says Tom Gnoske, of the Field Museum's Zoology Department and senior author of the paper. "However once we analyzed all of the statistical data we found a very strong correlation linking increased age and continued mane development, a significant variable ignored by all previous authors."........ Posted by: Ashley Permalink Source Wild Bees Make Honeybees Better Pollinators
"As honeybees become more scarce, it becomes more important to have better pollinators," said Sarah Greenleaf, a postdoctoral researcher at UC Davis and first author on the study. As a graduate student at Princeton University, Greenleaf carried out a two-year study of honeybees used to pollinate sunflower crops on farms in Yolo County, Calif., near UC Davis. Compared to honeybees, wild bees did not contribute much directly to crop pollination. But on farms where wild bees were abundant, honeybees were much more effective in pollinating flowers and generating seeds, Greenleaf found. There appear to be two reasons for that. Male wild bees, probably looking for mates, will latch onto worker honeybees, which are sterile females, causing them to move from one flower to another. Secondly, female wild bees appear to "dive bomb" honeybees, forcing them to move. Frequent movement between flowers spreads pollen around more effectively. Greenleaf and her co-author Claire Kremen, now a professor at UC Berkeley, calculated that wild bees contributed about $10 million of value to the $26-million sunflower industry alone......... Posted by: Ashley Permalink Source Watch Genes Activating In Live Tissue
Using multiphoton fluorescence microscopy, a technique pioneered at Cornell by physicist Watt W. Webb, scientists have for the first time been able to watch chromosomes change their form in order to activate their genes to synthesize key proteins in fruit fly cells. The advance could be a significant step toward understanding the basic processes that underlie gene expression. The discovery was the result of cross-disciplinary collaboration between Webb and John Lis, Cornell's Barbara McClintock Professor of Molecular Biology and Genetics. Jie Yao, who recently earned his Ph.D. at Cornell, initiated and facilitated the work. "This technology will revolutionize the way we see gene expression in organisms," said Lis. "We're watching transcription in real time in living cells". The research was described in the Aug. 31 issue of the journal Nature. The team's experiments focused on gene regulatory mechanisms: specifically, what happens in a cell's nucleus when an external stimulus (heat) prompts specific genes to activate, and how those activated genes direct the production of proteins that protect the fly against the stress of heating......... Posted by: Ashley Permalink Source Hidden Messages From Squid Skin
In research published recently in the journal Biology Letters, MBL (Marine Biological Laboratory) scientists Lydia Mäthger and Roger Hanlon present evidence that the polarized aspect of the skin of the longfin inshore squid, Loligo pealeii, is maintained after passing through the pigment cells responsible for camouflage. While the notion that a few animals produce polarization signals and use them in communication is not new, Mäthger and Hanlon's findings present the first anatomical evidence for a "hidden communication channel" that can remain masked by typical camouflage patterns. Their results suggest that it might be possible for squid to send concealed polarized signals to one other while staying camouflaged to fish or mammalian predators, most of which do not have polarization vision. Mäthger notes that these messages could contain information regarding the whereabouts of other squid, for example. "Whether signals could also contain information regarding the presence of predators (i.e., a warning signal) is speculation, but it may be possible," she adds......... Posted by: Ashley Permalink Source |
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