Month: March 2017
Was The Amazon Rainforest Man Made? Traditionally, historians have argued that the Amazon rainforest was sparsely populated prior to the arrival of Europeans, a cultural blackhole when compared to the richly populated rest of pre-Columbian South America. Extremely fertile land found radiating out from the remains of ancient settlements over the last few years has led some archaeologists to argue that for millennia people were enriching the relatively poor soil of the Amazon to use for farming. A study published by the Proceedings of the Royal Society of London B: Biological Sciences in 2015 went as far as to argue that a massive civilisation had once domesticated much of the land in the Amazon. They claimed that food production projections supported estimates of 8 million people living in the rainforest as late as 1492. Trees Support the Man Made Amazon Theory Levis and colleagues’ study used the Amazon’s trees as a means to look at the rainforest’s history of cultivation. “For many years, ecological studies ignored the influence of pre-Columbian peoples on the forests we see today. We found that a quarter of Amazonia’s domesticated species are widely distributed in the basin and dominate large expanses of forest. These results clearly indicate that the Amazonian flora is in part a surviving heritage of its past inhabitants,” Levis explained. The team overlayed data from over 1000 forest surveys of the Amazon Tree Diversity network on a map of over 3000 archaeological sites in the Amazon. Comparing forest composition at various distances from archaeological sites generated a picture of how pre-Colombian peoples influenced Amazon biodiversity. 85 tree species known to have been domesticated by ancient Amazonians for shelter, food or other uses formed the basis of the study. Remarkably, the team found that these 85 species were far more likely to be common in the tree surveys than non-domesticated species. These domesticated species were also found to be much more common close to archaeological sites. “This lays to rest the long-standing myth of the ’empty Amazon’,” says Charles Clement, senior researcher at INPA, Manaus, and a coauthor of the study. “Early European naturalists reported scattered indigenous populations living in huge and apparently virgin forests, and that idea has continued to fascinate the media, policy makers, development planners and even some scientists. This study confirms that even areas of the Amazon that look empty today are crowded with ancient footprints.” ]]>
New Scientist. “The results add to increasing evidence that these effects are often the outcome of changes to the genetic switches,” said Tony Capra of Vanderbilt University in Nashville, Tennessee. His own results published last year revealed Neanderthal influences on a variety of human disorders, including depression and addiction. The control of Neanderthal DNA decreased the most in regions of the brain critical for perception and fine motor skills, the basal ganglia and the cerebellum, which further evolved in humans to enable advanced thinking, behavior and the ability to process language. NTRK2 is another Neanderthal gene with fading influence. This gene is key to neuron survival in addition to the development of brain connections and its reduced influence illustrates the sort of fine-tuning which may have permitted our ancestors to take off intellectually. Another gene in which Neanderthal DNA lost control is a testes gene that affects a sperm’s ability to penetrate and subsequently fertilize an egg. Researchers theorize that once control of this gene was relinquished, neither the Neanderthals nor the human- Neanderthal hybrids were able to mate with humans. This theory is consistent with research results showing a reduction in the health of male offspring from hybrid unions. ]]>
Ancient Mesoamerica, can be found here]]>
history of the flightless seabirds. Situated in New Zealand’s Canterbury region, the fossil sites along the Waipara River have long been a vital resource to scientists for the abundance of avian fossils which became embedded in the sand just four million years after the dinosaurs went extinct. “Among the finds from these sites, the skeletons of Waimanu, the oldest known penguin to date, are of particular importance,” explained Dr. Gerald Mayr of the Senckenberg Research Institute in Frankfurt. Hugely significant is the fact the bones of the recently discovered giant penguin differ markedly from those of others from the same time period, suggesting there was much greater diversity among Paleocene penguins than previously assumed. In their study published in the Springer Journal Science of Nature, the team postulate that the newly discovered giant penguin fossil could point to the evolution of the birds having started much earlier than previously thought, perhaps even during the age of the dinosaurs. “What sets this fossil apart are the obvious differences compared to the previously known penguin remains from this period of geological history,” explained Mayr, an ornithologist from Frankfurt. “The leg bones we examined show that during its lifetime, the newly described penguin was significantly larger than its already described relatives. Moreover, it belongs to a species that is more closely related to penguins from later time periods.” Although impressive with its 1.5 metre length, the newly described giant penguin was still not as big as Anthropornis nordenskjoeld, the largest penguin fossil ever discovered, which lived on the Antarctic coast between 45 and 33 million years ago. Evidence has been found suggesting A.nordenskjoeld could reach heights of up to two metres from beak to toe. According to Mayr, it’s highly significant that the newly discovered penguin is much older than A.nordenskjoeld. “This shows that penguins reached an enormous size quite early in their evolutionary history, around 60 million years ago”. The team believe that the newly discovered species would have already adopted the unique, waddling gait which characterises modern penguins. This is something which would have distinguished it from other, more primitive species in the genus Waimanu – a genus of early penguin which lived during the Early Paleocene. “The discoveries show that penguin diversity in the early Paleocene was clearly higher than we previously assumed,” concluded Mayr, adding, “In turn, this diversity indicates that the first representatives of penguins already arose during the age of dinosaurs, more than 65 million years ago.” Image courtesy of Senckenberg Gesellschaft für Naturforschung (Senckenberg Nature Research Society) The newly published study is available from Sprnger Nature ]]>