Supersoldier Ants Reveal Evolutionary Secret | Social Insects & Atavisms When eight bizarrely big-headed soldier ants turned up in a wild colony collected from Long Island, N.Y., scientists knew they had found something interesting. This discovery of these oversized versions of soldier ants, whose job is to defend the nest, led researchers to create their own supersoldier ants in the lab with the help of a hormone, and, by doing so, offer an explanation for how ants, and possibly other social insects, take on specific forms with dedicated jobs within their colonies. It turns out these abnormal soldier ants were throwbacks to an ancestral state, one that no longer shows up within their species except, apparently, by accident. "It's been known for a long time that these kinds of slips occur, and they are viewed as the Barnum and Bailey of evolution," said the study's senior researcher Ehab Abouheif, Canada research chair in evolutionary developmental biology at McGill University. Meet the supersoldiers Making a supersoldier So why have supersoldiers?
Return of the super ants An entire genus of ants, comprising more than 1,000 species, has been found to have a hidden ability to make 'supersoldiers' — larger-than-average soldier ants that defend the nest against invaders. And all it takes is a dab of hormone. A few ant species of the Pheidole genus were already known to produce supersoldiers that deter invading army ants by blocking nest entrances with their enormous heads. Scientists have only ever seen these supersoldiers in 8 out of 1,100 Pheidole species. Photo courtesy of Alex Wild/alexanderwild.com Soldiers and supersoldiers from the hyper-diverse ant genus Pheidole marching side by side to defend their nest. The eight species that routinely produce supersoldiers are found only in the southwestern United States and in northern Mexico. Abouheif and his colleagues found that the ants’ supersoldier program is an extension of the same developmental events that set normal soldiers apart from workers. But that is not the case.
Telomere length in birds predicts longevity Protective caps known as telomeres that help to preserve the integrity of chromosomes can also predict lifespan in young zebra finches (Taeniopygia guttata), researchers have found. Telomeres are stretches of repetitive DNA sequence that are found at the ends of chromosomes, where they help to maintain cell viability by preventing the fraying of DNA and the fusion of one chromosome to another. The relationship between normal ageing and telomere decline has long been suspected — and even asserted by some companies that measure customers’ telomere length — but the link remains unproven in humans (see 'Spit test offers guide to health'). P. The lifespan of zebra finches is strongly correlated with the length of the chromosome caps that protect their DNA, known as telomeres, particularly at 25 days old. Most studies of longevity and telomere length have relied on only one or two measurements from an individual during their lifespan.
Resurrecting Evolution to Solve an 800-Million-Year-Old Puzzle | The Loom This is a story of about how the parts of a puzzle locked into place 800 million years ago. The puzzle is an ion pump that you can find in any mushroom, mold, or yeast. I’ve reproduced a picture of it here. Fungus cells, like our own cells, have lots of little pouches inside of them for carrying out special kinds of chemical reactions. In order for those reactions to work, there have to be a lot of positively-charged protons inside the pouches. This pump (which is is offically known as a vacuolar ATPase complex) is a wonderfully complex collection of proteins. Joe Thornton, a biologist at the University of Oregon, and his colleagues wondered how this pump came to be. The closest major group of species to fungi are animals. The scientists compared the genes for these ring proteins to other genes in order to reconstruct their evoluationary history. By comparing Vma3 and Vma11 in yeast, Thornton and his colleagues were able to infer the structure of their ancestral protein.
Giant Galapagos tortoise extinct for 150 years might still be alive | ZME Science Giant Galapagos Tortoises in Isabela Island, Galapagos. Adults of large subspecies can weigh over 300 kilograms (660lb) and measure 1.2 meters (4 ft) long. Although the maximum life expectancy of a wild tortoise is unknown, the average life expectancy is estimated to be 200 years. A subspecies of the the giant Galapagos tortoise, Chelonoidis elephantopus, long thought to be extinct for more than 150 years, is now believed to might still exist, scientists say. Yale University researchers conducted a highly thorough genetic analysis of various Galapagos giant tortoises in the region, which allowed them to speculate that at least a few dozen specimens of the elusive Chelonoidis elephantopus might still be alive! In 1835 during his antological Beagle expedition to the archipelago, Charles Darwin extensively studied the giant tortoises there, which he reserved a special chapter in his theory of evolution by natural selection. source
Trees Cocooned in Webs After Flood Photograph courtesy Russell Watkins, U.K. Department for International Development Trees shrouded in ghostly cocoons line the edges of a submerged farm field in the Pakistani village of Sindh, where 2010's massive floods drove millions of spiders and possibly other insects into the trees to spin their webs. Beginning last July, unprecedented monsoons dropped nearly ten years' worth of rainfall on Pakistan in one week, swelling the country's rivers. The water was slow to recede, creating vast pools of stagnant water across the countryside. "It was a very slow-motion kind of disaster," said Russell Watkins, a multimedia editor with the U.K.' According to Watkins, who photographed the trees during a trip to Pakistan last December, people in Sindh said they'd never seen this phenomenon before the flooding. (See pictures: "World's Biggest, Strongest Spider Webs Found.") As for what exactly had spun the webs, Watkins said: "There wasn't a scientific analysis of this being done. —Ker Than
Wrestling ninjas – why sabre-toothed predators have massive arms | Not Exactly Rocket Science A cat-like animal explodes from the long grass and leaps onto an antelope. Its huge bulk drags the target to the ground and its muscled forelegs pin it down. With two long sabre-shaped canine teeth, it stabs its victim in the throat, just the once, severing its blood vessels and windpipe. Death comes quickly. The hunter could be Smilodon, a sabre-toothed cat that lived throughout North and South America, around one or two million years ago. Or, it could be a nimravid, another group of hunters that looked like cats, but belonged to a separate, closely-related family. Or, it could be Barbourofelis, a member of yet another group of sabre-toothed not-quite-cats, which lived between 16 and 9 million years ago. Julie Meachen-Samuels from the National Evolutionary Synthesis Center has shown that all three groups shared the same adaptations: massive powerful front legs for pinning their prey, and strikingly large canines for delivering precise one-hit kills. Reference: Meachen-Samuels. 2011.
Fossils Reveal Secrets of Insects' Weird Ears | Evolution of Hearing | Fossil Insects & Green River Formation Various species of insects boast ears in the strangest places, including on their necks and under their wings. Now, a new examination of 50-million-year-old cricket and katydid fossils finds that these odd ears evolved before even the appearance of the predators that these ears can hear. Crickets, moths and other flying insects can hear the ultra high-pitched sonar of hunting bats, a talent that helps them avoid being eaten. "Their bat-detecting abilities may have simply become apparent later," study researcher Dena Smith of the University of Colorado, Boulder, said in a statement. Insects have evolved ears at least 17 times in different lineages, and other insects, such as the blue morpho butterfly, may even be able to distinguish between low and high pitches with their primitive under-wing ears. That level of detail is key, because the researchers were looking for katydid and cricket ears. "The next step," Smith said, "is to look for ears in other insect groups."
Yılın kitabı Türkiye'den - Doğal Hayat Güncelleme: 09:45 TSİ 02 Ocak. 2012 Pazartesi KuzeyDoğa Derneği Başkanı Doç. Dr. Çevre, doğa tarihi ve yaban hayat konularında dünyanınen kapsamlı ve saygın yayınevi olan İngiliz Natural History Book Service, 2011yılında yayınlanmış, en ilginç, orijinal ve bilgilendirici, okuyuculara yeni bakış açıları kazandıran, eski konulara yeni yaklaşımlar getiren ve insanları daha fazla anlamaya ve araştırmaya yönelten 10 kitap listesini yayınladı. Yayınevi 2011’de yılın kitabı seçtiği bu kitaplailgili yaptığı açıklamada şu sözlere yer verdi, “Kuşlar, hâli hazırda etkilerini gördüğümüz iklim değişikliği konusunda bizi uyarıyor. Düşük Yüksek 24 kullanıcıdan 4.5 puan.
A Touch of Understanding: Gene Tweak Opens Sensory Black Box | Wired Science A new technique for color-coding nerves involved in touch gives neuroscientists a much-needed tool for studying that mysterious sense. For nearly 250 years, the intricate detail and complexity of skin’s nervous-system wiring has thwarted attempts at understanding it. But if researchers studying skin could be imagined as technicians reverse-engineering a supercomputer’s peripherals, they’d have just traced about four lines back to the motherboard. “Of all five major senses, the skin sense is the least understood. 'Of all five major senses, the skin sense is the least understood. More obstacles to decoding touch are clusters of tissue called ganglia. To untangle the wiring, Woodbury and other researchers led by neuroscientist David Ginty of Johns Hopkins University began with mouse nervous systems. The researchers identified genes active only in types of LTMRs at the base of ultra-sensitive hairs. Updated: Dec. 29, 2011; 10 p.m.
The Evolution of Antibiotic Resistance: Insight into the Roles of Molecular Mechanisms of Resistance and Treatment Context - - R. Craig MacLean - Discovery Medicine Abstract: The widespread use of antibiotics has markedly improved public health over the last 60 years. However, the efficacy of antibiotic treatment is rapidly decreasing as a result of the continual spread of antibiotic resistance in pathogen populations. The evolution of antibiotic resistance is an amazingly simple example of adaptation by natural selection, and there is growing interest among evolutionary biologists in using evolutionary principles to help understand and combat the spread of resistance in pathogen populations. In this article, we review recent progress in our understanding of the underlying evolutionary forces that drive antibiotic resistance. Introduction The classic model for the evolution of antibiotic resistance is as follows (Figure 1). Figure 1. Molecular Mechanisms Figure 2. Bacteria acquire antibiotic resistance as a result of spontaneous chromosomal mutations, or by acquiring plasmid-borne resistance alleles by horizontal gene transfer. Treatment Context
High genetic diversity in an ancient Hawaiian clone Public release date: 22-Dec-2011 [ Print | E-mail Share ] [ Close Window ] Contact: Anna FarneskiAfarnesk@ramapo.edu 201-684-6844Wiley-Blackwell The entire Hawaiian population of the peat moss Sphagnum palustre appears to be a clone that has been in existence for some 50,000 years researchers have discovered. The study is published in New Phytologist. Among the most long-lived of organisms, every plant of the Hawaiian population appears to have been produced by vegetative rather than sexual propagation and can be traced back to a single parent. Surprisingly, the genetic diversity of the Hawaiian clone is comparable to that detected in populations of S. palustre that do propagate sexually and occur across vaster regions. As the Hawaiian Islands are the most remote high volcanic island system in the world, the comparatively high genetic diversity detected in the Hawaiian population of S. palustre is unusual. [ Print | E-mail AAAS and EurekAlert!
Chinese fossils shed light on the evolutionary origin of animals from single-cell ancestors Posted by TANNChina, Evolution, Fossils, Origin of Life, Palaeontology1:00 PM Evidence of the single-celled ancestors of animals, dating from the interval in Earth's history just before multicellular animals appeared, has been discovered in 570 million-year-old rocks from South China by researchers from the University of Bristol, the Swedish Museum of Natural History, the Paul Scherrer Institut and the Chinese Academy of Geological Sciences. All life evolved from a single-celled universal common ancestor, and at various times in Earth history, single-celled organisms threw their lot in with each other to become larger and multicellular, resulting, for instance, in the riotous diversity of animals. However, fossil evidence of these major evolutionary transitions is extremely rare. The researchers studied the microscopic fossils using high energy X-rays at the Swiss Light Source in Switzerland, revealing the organisation of the cells within their protective cyst walls.
Dr. Ömer Gökçümen ile evrimin genetiği üzerine Açık Bilim Cepyayını’nın ikincisini, evrim genetiği üzerinde çalışan Dr. Ömer Gökçümen ile yaptık. Podcast: Play in new window | Download Dr. Ömer Gökçümen Dr. Bunun yanı sıra yazıya da önem veriyor, Shepherds of Arcadia adlı bir güncenin kurucusu, ve Radikal gazetesinde yazıları yayınlanıyor. Kendisine söyleşi için bir kez daha teşekkür ederiz. Şekil 1. Notlar Kopya sayısı değişiklikleri bir değişinim (mutasyon) türüdür (Şekil 1). Bunu beğen: Beğen Yükleniyor...