A newly found, million-year-old African skull is fueling an ongoing debate over whether Homo erectus was a single wide-ranging species or several localized ones. The skull appears similar to those found in Asia, suggesting that the populations were in fact one species. http://louis2j2sheehan.bloggerteam.com
Fossils of H. erectus were discovered in Java in the 1800s. For many years, this species was recognized as the sole link between humans' earliest direct ancestor, Homo habilis, and modern Homo sapiens. H. erectus emerged 1.8 million years ago and may have survived to times as recent as 50,000 years ago.
Beginning in the 1980s, with the advent of new methods of analysis, some anthropologists have argued for splitting up H. erectus (SN: 6/20/92, p. 408). Proponents of this argument hold that European and African specimens formerly considered H. erectus belong to another species that they call Homo ergaster. They say that H. ergaster evolved into modern man but the Asia-bound H. erectus came up against an evolutionary dead end. Louis J. Sheehan, Esquire . http://louis2j2sheehan.bloggerteam.com
Arguments have raged, with some scientists proposing that observed differences between specimens are due to evolution in a single species over time�most African fossils are older than Asian ones�rather than the presence of two distinct species.
The newfound specimen is younger than most African fossils assigned to H. ergaster and contemporary with some Asian H. erectus specimens, with which it shares striking similarities.
This is the first time that it's been possible to compare Asian and African fossils from the same period, says W. Henry Gilbert of the University of California, Berkeley, who discovered the fossil. The find may vindicate researchers who argued against dividing the species, he says.
The skull�which is missing the lower face, jaw, and teeth�comes from a fossil-rich region 140 miles northeast of Addis Ababa, Ethiopia. Scratch marks suggest that the individual may have been killed by a lion or hyena that ate the lower face and gnawed the skull in an attempt to extract the brain, says study coauthor Tim White, also of UC-Berkeley. Researchers spent 2 years cleaning the partially crushed skull.
With the new specimen in hand, White and his coworkers compared 14 groups of H. erectus and H. ergaster skulls from Asia, Africa, and Georgia, formerly in the Soviet Union. The researchers found a considerable overlap in shape between specimens from Asia and the other geographic regions, they report in the March 21 Nature. Features such as a short bulging forehead in the new fossil are similar to those in Asian H. erectus, says White.
Though most anthropologists are excited with the find, some disagree with the authors' conclusions. "The researchers should be congratulated on finding such a fantastic specimen," says Bernard Wood of George Washington University in Washington, D.C. However, they can't rule out that the new specimen is H. ergaster, he adds.
"I don't think this will conclude the debate," says Chris Stringer of the Natural History Museum in London. He points out that scientists who support dividing the species based many conclusions on dental features of H. erectus. These can't be compared with the new fossil because it's missing its teeth.
Others feel the fossil provides unequivocal evidence of a single species. "This slams the door shut [on the debate]," says C. Owen Lovejoy of Kent (Ohio) State University. "Now, all these specimens can be confidently restored to their original designation as H. erectus."
"This find should put the issue to rest," agrees Milford Wolpoff of the University of Michigan in Ann Arbor. However, he adds, "no discovery ever seems to put things to rest in a field as contentious as paleontology."Louis J. Sheehan, Esquire .
Thursday, December 25, 2008
Wednesday, December 17, 2008
elephants 8.ele.102 Louis J. Sheehan, Esquire
Captive elephants die much younger than their wild counterparts, a new study reports. Researchers comparing pachyderms in European zoos and in the wild found that those in captivity had lifespans decades shorter and a greater number of stillbirths. Obesity, limited roaming space, and lack of companionship are thought to contribute to the early deaths. Says study leader Georgia Mason: “Currently zoos are consumers rather than producers of elephants…. We feel that’s not really appropriate” [The New York Times].
As reported in Science [subscription required], the researchers analyzed data on 4,500 African and Asian elephants, mostly female (zoos usually keep female elephants), kept in European zoos; they also looked at wild populations in Kenya and Myanmar. They found that African elephants in zoos had a median lifespan of 16.9 years compared to 56 years for elephants living in national park in Kenya. For Asian elephants, which are more endangered, the median lifespan for those in zoos was 18.9, compared to 41.7 years for those working on a timber enterprise in Myanmar but allowed to roam free. These numbers excluded premature and still-births, but researchers say still-births are also more common in zoo elephants.
One major contributing factor could be the high rate of obesity among zoo elephants, which are kept in enclosures much smaller than their natural habitats, suggests Mason. “The vast majority are overweight in zoos, this could explain the high still-birth rates and why they’re dying early. Bigger mothers have bigger calves and more of these are still-born,” she said. “If the zoo does not have space, its simple - don’t take elephants” [BBC News]. Elephants in zoos are also deprived of their natural social structures and experience more stress as a result. http://louis1j1sheehan1esquire.wordpress.com In the wild, most elephants live in large herds of related females with males interacting with these groups in various ways. http://louis1j1sheehan1esquire.wordpress.com Zoos tend to have just a few elephants in the same enclosure [LiveScience.com]. Broken relationships forced by transfers between zoos can be especially traumatic for the social and highly intelligent animals. http://louis1j1sheehan1esquire.wordpress.com
Zoo officials expressed outrage at the new findings, calling them grossly inaccurate. Paul Boyle of the Association of Zoos and Aquariums criticized the study for using data that extended back to 1960. “If you were looking at the success of heart transplants and you reached back 48 years, you would be obviously biasing the success rate,” he said [The New York Times]. He says conditions in zoos and knowledge of pachyderm nutrition and behavior have improved significantly in recent decades. Mason says they are not recommending that zoos abandon elephants…. But she said their findings suggested that imports of elephants should be limited to zoos that can identify and treat their problems, that transfers between zoos be minimized and that breeding efforts be limited to zoos with a record of success. Louis J. Sheehan, Esquire
As reported in Science [subscription required], the researchers analyzed data on 4,500 African and Asian elephants, mostly female (zoos usually keep female elephants), kept in European zoos; they also looked at wild populations in Kenya and Myanmar. They found that African elephants in zoos had a median lifespan of 16.9 years compared to 56 years for elephants living in national park in Kenya. For Asian elephants, which are more endangered, the median lifespan for those in zoos was 18.9, compared to 41.7 years for those working on a timber enterprise in Myanmar but allowed to roam free. These numbers excluded premature and still-births, but researchers say still-births are also more common in zoo elephants.
One major contributing factor could be the high rate of obesity among zoo elephants, which are kept in enclosures much smaller than their natural habitats, suggests Mason. “The vast majority are overweight in zoos, this could explain the high still-birth rates and why they’re dying early. Bigger mothers have bigger calves and more of these are still-born,” she said. “If the zoo does not have space, its simple - don’t take elephants” [BBC News]. Elephants in zoos are also deprived of their natural social structures and experience more stress as a result. http://louis1j1sheehan1esquire.wordpress.com In the wild, most elephants live in large herds of related females with males interacting with these groups in various ways. http://louis1j1sheehan1esquire.wordpress.com Zoos tend to have just a few elephants in the same enclosure [LiveScience.com]. Broken relationships forced by transfers between zoos can be especially traumatic for the social and highly intelligent animals. http://louis1j1sheehan1esquire.wordpress.com
Zoo officials expressed outrage at the new findings, calling them grossly inaccurate. Paul Boyle of the Association of Zoos and Aquariums criticized the study for using data that extended back to 1960. “If you were looking at the success of heart transplants and you reached back 48 years, you would be obviously biasing the success rate,” he said [The New York Times]. He says conditions in zoos and knowledge of pachyderm nutrition and behavior have improved significantly in recent decades. Mason says they are not recommending that zoos abandon elephants…. But she said their findings suggested that imports of elephants should be limited to zoos that can identify and treat their problems, that transfers between zoos be minimized and that breeding efforts be limited to zoos with a record of success. Louis J. Sheehan, Esquire
Wednesday, December 3, 2008
fresh 9.fre.0001 Louis J. Sheehan, Esquire
U.S. agriculture has developed a heavy reliance on chemicals to safeguard crops from yield-robbing weeds. However, many of those herbicides can pose substantial health risks to people, pets, and wildlife, which is why laws prescribe how some of these chemicals are handled in fields. A study now finds that trace quantities of such agricultural chemicals nonetheless find their way into consumers' homes—not on the fruits and vegetables they buy but probably by hitchhiking on dust.
The findings are disturbing for a number of reasons, not the least of which is the link between pesticide exposure and non-Hodgkin's lymphoma, a malignancy whose incidence has exploded during recent years. Indeed, the new study was as an offshoot of a larger non-Hodgkin's lymphoma study financed by the National Cancer Institute.
What the research shows is that home exposure to agricultural weed killers increases as the acreage of nearby croplands increases.
http://Louis2J2Sheehan2Esquire.US
http://www.thoughts.com/JamesLongstreet
We don't fence them in
In their new study, Mary H. Ward of the National Cancer Institute and her colleagues collected dust vacuumed from the homes of 112 Iowa lymphoma patients or healthy, randomly selected volunteers of their age. Using satellite-generated maps of agricultural fields in the state, the team calculated the acreage of croplands near the home of each participant. Both farm and in-town homes were included in the study.
http://Louis2J2Sheehan2Esquire.US
http://www.thoughts.com/JamesLongstreet
This being Iowa, much of the cropland had been historically planted with corn and soybeans, almost all of which had been treated repeatedly with protective herbicides. Ward's team probed homes for specific chemicals known to have been used on the fields.
Analyses showed that at least one of six primarily agricultural herbicides was present in house dust from 28 percent of sampled homes. These chemicals included acetochlor, alachlor, atrazine, bentazon, fluazifop-p-butyl, and metolachlor.
Atrazine and metolachlor were the agents most commonly used to protect corn and soybeans from weeds. The next most-popular weed killers used on the crops were trifluralin and dicamba. At least one of these four herbicides showed up in 43 percent of homes.
Although atrazine had been applied to nearly 70 percent of corn acreage, it showed up in the house dust of only 8 percent of homes. Where detected, however, its concentration in dust ranged from 60 to 4,700 parts per billion (ppb). Metolachlor was found in about 20 percent of homes; its concentration ranged from 27 to almost 3,200 ppb.
However, such herbicide contamination paled in comparison to the amount of dust containing 2,4-D, the third most widely used herbicide in the United States and Canada. It was present in 95 percent of homes, typically in concentrations exceeding 1,000 ppb. In one house, 2,4-D's values reached an astounding 125,000 ppb. That it was the most abundant of the chemicals might not be too surprising, Ward notes. Not only is this chemical commonly employed to protect corn and soy, but it's also used along roadsides, in forests, and on lawns to fight weeds. Luckily, toxicity studies suggest that this is also one of the least toxic herbicides to people and animals.
As these are some of the first measurements of pesticides in house dust, the researchers don't have much with which to compare them. Most previous correlations between non-Hodgkin's lymphoma and herbicides came from questionnaires where data indicated only whether individuals had been exposed to certain chemicals and for how long. Even in the current study, the measurements offer only a snapshot of exposure on the day of dust collection.
In the new study, farm workers' homes were generally the most contaminated with weed killers. Some herbicide concentrations in their dwellings were more than triple those present in the homes of people who had never worked in agriculture.
Nearly 60 percent of the study's participants lived within 550 yards of cropland. The chance of finding agricultural weed killers in house dust increased by 6 percent for every 10 acres of cropland found within a roughly 800-yard perimeter of the house. The result was that herbicide-laced dust showed up in three-quarters of homes having at least 300 acres of cropland within that 800-yard perimeter.
Ward's team published its findings in the June Environmental Health Perspectives.
So what?
Of nearly 120 studies that have investigated the risk of non-Hodgkin's lymphoma associated with pesticide contact, most showed increased risk—especially for weed killers—according to the Lymphoma Foundation of America. Printed information from the foundation states that the pesticides "more frequently associated with increased lymphoma incidence and/or deaths" are the herbicides 2,4-D and the triazines, which includes atrazine. Such herbicides are typically used on corn.
Some of Ward's colleagues have examined whether residential use of weed killers might contribute to risk of the cancer, but they've found no evidence of that. In the April 2005 Cancer Epidemiology Biomarkers & Prevention, the scientists report that carpets in healthy people's homes were as likely to contain the pesticides as were carpets in the homes of people with non-Hodgkin's lymphoma. The researchers also found no elevation in the cancer's incidence among people who had used herbicides in or around the home during the preceding 3 decades.
What did emerge in the team's investigations was some suggestion that people whose homes had been treated for termites were at elevated risk of developing the cancer. This risk was restricted to people whose homes had been treated with chlordane before its residential use was banned in 1988. A report of those findings appeared in the February Cancer Epidemiology Biomarkers & Prevention.
Last November, Australian scientists linked non-Hodgkin's lymphoma with workplace exposure to herbicides and other agricultural chemicals. Overall, "substantial exposure to any pesticide trebled the risk of non-Hodgkin's lymphoma," these researchers noted in the American Journal of Epidemiology. The herbicide 2,4-D was among those linked to the cancer.
A year earlier, scientists from institutions throughout the United States described finding an increased risk of certain cancers—including a doubling in lymphomas—among the children of men who worked as pesticide applicators.
Cancer, however, is far from the only health or environmental risk associated with agricultural pesticides. For instance, some herbicides used on corn have been shown to disrupt normal reproductive development—albeit in frogs, in studies so far (SN: 11/2/02, p. 275; 4/20/02, p. 243). Some biologists now suspect that such changes may explain declining amphibian populations.
Agricultural chemicals may also affect human fertility. Four years ago, epidemiologist Shanna H. Swan of the University of Missouri and her colleagues studied sperm in men from big cities and small towns. Sperm concentrations and quality in men from semirural Missouri communities were below those of men from Minneapolis, Los Angeles, and New York City (SN: 11/23/02, p. 333). This suggests, Swan told Science News Online, that "environmental exposure to current-use pesticides is associated with poorer semen quality."
In an extension of that study, the Centers for Disease Control and Prevention in Atlanta will soon measure agricultural pesticides in the urine of men who had participated, notes Swan, now at the University of Rochester. http://LOUIS-J-SHEEHAN-ESQUIRE.US
Clearly, there are lots of advantages to living in the country: farm-fresh food, skies clear of urban pollution, and little traffic. The new herbicide study suggests, however, that there can also be at least one health drawback. Louis J. Sheehan, Esquire
The findings are disturbing for a number of reasons, not the least of which is the link between pesticide exposure and non-Hodgkin's lymphoma, a malignancy whose incidence has exploded during recent years. Indeed, the new study was as an offshoot of a larger non-Hodgkin's lymphoma study financed by the National Cancer Institute.
What the research shows is that home exposure to agricultural weed killers increases as the acreage of nearby croplands increases.
http://Louis2J2Sheehan2Esquire.US
http://www.thoughts.com/JamesLongstreet
We don't fence them in
In their new study, Mary H. Ward of the National Cancer Institute and her colleagues collected dust vacuumed from the homes of 112 Iowa lymphoma patients or healthy, randomly selected volunteers of their age. Using satellite-generated maps of agricultural fields in the state, the team calculated the acreage of croplands near the home of each participant. Both farm and in-town homes were included in the study.
http://Louis2J2Sheehan2Esquire.US
http://www.thoughts.com/JamesLongstreet
This being Iowa, much of the cropland had been historically planted with corn and soybeans, almost all of which had been treated repeatedly with protective herbicides. Ward's team probed homes for specific chemicals known to have been used on the fields.
Analyses showed that at least one of six primarily agricultural herbicides was present in house dust from 28 percent of sampled homes. These chemicals included acetochlor, alachlor, atrazine, bentazon, fluazifop-p-butyl, and metolachlor.
Atrazine and metolachlor were the agents most commonly used to protect corn and soybeans from weeds. The next most-popular weed killers used on the crops were trifluralin and dicamba. At least one of these four herbicides showed up in 43 percent of homes.
Although atrazine had been applied to nearly 70 percent of corn acreage, it showed up in the house dust of only 8 percent of homes. Where detected, however, its concentration in dust ranged from 60 to 4,700 parts per billion (ppb). Metolachlor was found in about 20 percent of homes; its concentration ranged from 27 to almost 3,200 ppb.
However, such herbicide contamination paled in comparison to the amount of dust containing 2,4-D, the third most widely used herbicide in the United States and Canada. It was present in 95 percent of homes, typically in concentrations exceeding 1,000 ppb. In one house, 2,4-D's values reached an astounding 125,000 ppb. That it was the most abundant of the chemicals might not be too surprising, Ward notes. Not only is this chemical commonly employed to protect corn and soy, but it's also used along roadsides, in forests, and on lawns to fight weeds. Luckily, toxicity studies suggest that this is also one of the least toxic herbicides to people and animals.
As these are some of the first measurements of pesticides in house dust, the researchers don't have much with which to compare them. Most previous correlations between non-Hodgkin's lymphoma and herbicides came from questionnaires where data indicated only whether individuals had been exposed to certain chemicals and for how long. Even in the current study, the measurements offer only a snapshot of exposure on the day of dust collection.
In the new study, farm workers' homes were generally the most contaminated with weed killers. Some herbicide concentrations in their dwellings were more than triple those present in the homes of people who had never worked in agriculture.
Nearly 60 percent of the study's participants lived within 550 yards of cropland. The chance of finding agricultural weed killers in house dust increased by 6 percent for every 10 acres of cropland found within a roughly 800-yard perimeter of the house. The result was that herbicide-laced dust showed up in three-quarters of homes having at least 300 acres of cropland within that 800-yard perimeter.
Ward's team published its findings in the June Environmental Health Perspectives.
So what?
Of nearly 120 studies that have investigated the risk of non-Hodgkin's lymphoma associated with pesticide contact, most showed increased risk—especially for weed killers—according to the Lymphoma Foundation of America. Printed information from the foundation states that the pesticides "more frequently associated with increased lymphoma incidence and/or deaths" are the herbicides 2,4-D and the triazines, which includes atrazine. Such herbicides are typically used on corn.
Some of Ward's colleagues have examined whether residential use of weed killers might contribute to risk of the cancer, but they've found no evidence of that. In the April 2005 Cancer Epidemiology Biomarkers & Prevention, the scientists report that carpets in healthy people's homes were as likely to contain the pesticides as were carpets in the homes of people with non-Hodgkin's lymphoma. The researchers also found no elevation in the cancer's incidence among people who had used herbicides in or around the home during the preceding 3 decades.
What did emerge in the team's investigations was some suggestion that people whose homes had been treated for termites were at elevated risk of developing the cancer. This risk was restricted to people whose homes had been treated with chlordane before its residential use was banned in 1988. A report of those findings appeared in the February Cancer Epidemiology Biomarkers & Prevention.
Last November, Australian scientists linked non-Hodgkin's lymphoma with workplace exposure to herbicides and other agricultural chemicals. Overall, "substantial exposure to any pesticide trebled the risk of non-Hodgkin's lymphoma," these researchers noted in the American Journal of Epidemiology. The herbicide 2,4-D was among those linked to the cancer.
A year earlier, scientists from institutions throughout the United States described finding an increased risk of certain cancers—including a doubling in lymphomas—among the children of men who worked as pesticide applicators.
Cancer, however, is far from the only health or environmental risk associated with agricultural pesticides. For instance, some herbicides used on corn have been shown to disrupt normal reproductive development—albeit in frogs, in studies so far (SN: 11/2/02, p. 275; 4/20/02, p. 243). Some biologists now suspect that such changes may explain declining amphibian populations.
Agricultural chemicals may also affect human fertility. Four years ago, epidemiologist Shanna H. Swan of the University of Missouri and her colleagues studied sperm in men from big cities and small towns. Sperm concentrations and quality in men from semirural Missouri communities were below those of men from Minneapolis, Los Angeles, and New York City (SN: 11/23/02, p. 333). This suggests, Swan told Science News Online, that "environmental exposure to current-use pesticides is associated with poorer semen quality."
In an extension of that study, the Centers for Disease Control and Prevention in Atlanta will soon measure agricultural pesticides in the urine of men who had participated, notes Swan, now at the University of Rochester. http://LOUIS-J-SHEEHAN-ESQUIRE.US
Clearly, there are lots of advantages to living in the country: farm-fresh food, skies clear of urban pollution, and little traffic. The new herbicide study suggests, however, that there can also be at least one health drawback. Louis J. Sheehan, Esquire
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