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Evolutionary Consequences Of Bluebird Aggression
This study, conducted by Renee Duckworth, Ph.D., suggests the birds may play more active roles in their own natural selection than traditional models of evolution would support. "The traditional view of evolution is that organisms are passive creatures on which natural selection operates," said Duckworth, who just completed her doctoral training at Duke. But her research results, published online on Wednesday, April 12, 2006, in the journal Proceedings of the Royal Society B, suggest a different model, at least among these bluebirds. "By selecting the environment in which they live, animals can actively affect the natural selection they experience," Duckworth said in an interview. "The main message of this study is that the ability of organisms to choose their environment needs to be made a more explicit part of evolutionary theory". In her studies, funded by the National Science Foundation, Duckworth followed up on previous findings that adult western bluebirds aggressively defend large breeding territories and also use different foraging strategies in wooded and open habitats......... Posted by: Ashley Permalink Source Global Warming May Lead To Mass Species Extinctions
Given its potential to damage areas far away from human habitation, the study finds that global warming represents one of the most pervasive threats to our planet's biodiversity - in some areas rivaling and even surpassing deforestation as the main threat to biodiversity. The study expands on a much-debated 2004 paper reported in the journal Nature that suggested a quarter of the world's species would be committed to extinction by 2050 as a result of global warming. This latest study picks up where the Nature paper left off, incorporating critiques and suggestions from other researchers while increasing the global scope of the research to include diverse hotspots around the world. The results reinforce the massive species extinction risks identified in the 2004 study. "Climate change is rapidly becoming the most serious threats to the planet's biodiversity," said lead author Dr. Jay Malcolm, an assistant forestry professor at the University of Toronto. "This study provides even stronger scientific evidence that global warming will result in catastrophic species loss across the planet."........ Posted by: Ashley Permalink Source Ants Arose 140-168 Million Years Ago
But these resilient insects, now found in terrestrial ecosystems the world over, apparently began to diversify only about 100 million years ago in concert with the flowering plants, the scientists say. "This study integrates numerous fossil records and a large molecular data set to infer the evolutionary radiation of ants, which have deeper roots than we thought," said Chuck Lydeard, program director in NSF's Division of Environmental Biology, which funded the research. The study was also supported by the Green Fund. Led by biologists Corrie Moreau and Naomi Pierce of Harvard University, the researchers reconstructed the ant family tree using DNA sequencing of six genes from 139 representative ant genera, encompassing 19 of 20 ant subfamilies around the world. "Ants are a dominant feature of nearly all terrestrial ecosystems, and yet we know surprisingly little about their evolutionary history: the major groupings of ants, how they are related to each other, and when and how they arose," said Moreau. "We now have a clear picture of how this extraordinarily dominant - in ecological terms - and successful - in evolutionary terms - group of insects originated and diversified"......... Posted by: William Permalink Source War between the sexes influences evolution
Birds, butterflies, and snakes have a genetic war between the sexes that influences the way they evolve, according to a new theory published in the April 7 issue of the journal Science. "Genetic conflict is of great interest in evolutionary biology," explained first author Paige M. Miller. Miller is a postdoctoral fellow in the Department of Ecology, Evolution and Marine Biology (EEMB) at the University of California, Santa Barbara. The recent publication of the chicken genome has sparked new interest in ZW species, explained William R. Rice, co-author and professor in the Department of EEMB at UC Santa Barbara. Chickens serve as model organisms in many areas of research. Unlike mammals, the females are heterozygous; they have two different sex chromosomes, Z and W. In the human female, the sex chromosomes are XX; they are homozygous. Butterflies, birds and snakes are ZW species. The authors explain that maternal-effect genes are those that are expressed in the mother, are packaged in the egg, and influence the development of offspring. "We think that the maternal-effect genes are a new arena for conflict in ZW species," said Rice. "The mathematical models support this conclusion. 'Son killers' are predicted to accumulate on the W chromosome and 'daughter killers' to accumulate on the Z"......... Posted by: Ashley Permalink Source Filling the Evolutionary Gap Between Fish and Land Animals
Credit: Zina Deretsky, National Science Foundation
The new species has a skull, neck, ribs, and parts of a fin that resemble the earliest limbed animals, called tetrapods. But the creature also has fins and scales like a fish. "This animal is both fish and tetrapod. We jokingly call it a fishapod," said Neil Shubin of the University of Chicago. He and paleontologists from the Academy of Natural Sciences in Philadelphia, the University of Chicago, and Harvard University conducted the research. They report the finding in two papers published this week in the journal Nature. "Paleontologists have known that animals first appeared on land in the Devonian Period," said Richard Lane, program director in the National Science Foundation (NSF)'s division of earth sciences, which funded the research. "To reach this evolutionary milestone, a skeletal progression from fish to land-roaming tetrapods would have been needed. Now we have new evidence of that progression". The back of the animal's skull, neck, ribs and fins "are especially tetrapod-like while the snout, lower jaws, and scale-cover are similar to those seen in closely related fish," Shubin said. The animal was a predator with sharp teeth, a crocodile-like head and a flattened body......... Posted by: William Permalink Source Monitoring Plant Health
Funded under the European Commission's FET (Future and Emerging Technologies) initiative of the IST programme, the PLANTS project sought to develop a unique system that linked plants, technology and people to continuously assess the state of crop health. Using sensors, transmitters and specialist software, the system monitors the state of the crop on a plant-by-plant basis, in near real-time. Dr Anthony Morrissey at Tyndall National Institute (Ireland) led the project which included partners from University College Cork (Ireland), Computer Technology Institute (CTI, Greece) and Eden Project Ltd (UK). "You could almost walk away from the crop and let it grow on its own," says Dr Fiona Tooke of the Eden Project, a unique public education facility in the UK's Cornwall region that gathers all the planet's major agricultural systems under a series of spectacular, and immense, plastic domes that function as high tech glasshouses. Eden joined the PLANTS project to help promote, and disseminate the ideas and philosophy behind the project......... Posted by: Ashley Permalink Source Scent Of A Lady Spider
Female Australian redback spider eating male spider, Image: Ken Jones, UTSC
Not the ideal honeymoon, perhaps. But redback males, who get only one mating opportunity - an uncommon occurrence in nature - have a few tricks up their (eight) sleeves. A new study by researchers at the University of Toronto at Scarborough has identified developmental adaptations in male Australian redback spiders (Latrodectus hasselti) that give these guys an edge in their deadly dating game. The study in the April 4 issue of Current Biology reports that males develop faster based on the population density of males and females around them - the first time such a phenomenon has been shown in any animal. "It shows that males are really tracking the selection pressures that they're facing in an environment - they're aware of male density and the amount of competition they're going to be facing," says Michael Kasumovic, a PhD candidate in the UTSC laboratory of Professor Maydianne Andrade. "It's the first time that it's been shown that males are actually changing their development in response to both sexual and natural selection"......... Posted by: Ashley Permalink Source Birds dodge Malta massacre
Restrictions are being imposed on the annual shoot of wild birds on the small Mediterranean island. Some of the estimates of birds killed annually by thousands of Maltese shotgun hunters include 200,000 to 300,000 song thrushes; 100,000 to 200,000 turtle doves; 50,000 to 100,000 robins; 20,000 to 50,000 skylarks; 40,000 swifts, swallows and house martins; 5000 to 8000 nightjars; and 3000 to 5000 marsh harriers......... Posted by: Ashley Permalink Source Canadian Prairies Facing Water Crisis
"The western prairies are worse than other areas of Canada," said Schindler, co-author of a paper published in the journal "Proceedings of National Academy of Sciences," early online edition. "One of the referees on this paper said, 'wow, this is like looking out the window of a locomotive 10 seconds before the train crashes.' It is a very dire situation". Although most global studies rank Canada among the top five countries in terms of per-capita water supply, those rankings can be deceptive, argue Schindler and Dr. Bill Donahue, who co-authored the paper. Canada's western prairie provinces (WPP), for example, have an area of 2 million kms that lie in the rain shadow of the Rocky Mountains and as a result, are the driest large area of southern Canada. Little research has been done on the cumulative effects of climate warming, drought and human activity on water shortages. Schindler and Donahue found that the biggest threat was a combined one, made up of several ingredients. First, there is now considerable evidence that the 20th century, when settlers arrived, was the wettest century for at least a couple of millenia. What we think of as normal was not normal in the long-term. "Most earlier centuries had one or more prolonged droughts, some of 10-40 years," said Schindler. "So we should probably not expect a second wet century in a row"......... Posted by: Ashley Permalink Source 57 Billion Dollar Service By Insects
"Most insects tirelessly perform functions that improve our environment and lives in ways that scientists are only beginning to understand," Losey says. "Don't let the insects' small stature fool you - these minute marvels provide valuable services". The study found that native insects are food for wildlife that supports a $50 billion recreation industry, provide more than $4.5 billion in pest control, pollinate $3 billion in crops and clean up grazing lands, which saves ranchers some $380 million a year. And these are "very conservative" estimates that probably represent only a fraction of the true value, reports Losey, associate professor of entomology at Cornell. This analysis of the economic value of these insect services is the first analysis of its type, said Losey, who co-authored the study with Mace Vaughan, Cornell M.S. '99, conservation director of the Xerces Society for Invertebrate Conservation in Portland, Ore., which works to protect native insect habitats through education and research......... Posted by: Ashley Permalink Source |
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