The honeybee (Apis mellifera) is of crucial importance for humanity. One third of our food is dependent on the pollination of fruits, nuts and vegetables by bees and other insects. Extensive losses of honeybee colonies in recent years are a major cause for concern. Honeybees face threats from disease, climate change, and management practices. To combat these threats it is important to understand the evolutionary history of honeybees and how they are adapted to different environments across the world.
“We have used state-of-the-art high-throughput genomics to address these questions, and have identified high levels of genetic diversity in honeybees. In contrast to other domestic species, management of honeybees seems to have increased levels of genetic variation by mixing bees from different parts of the world. The findings may also indicate that high levels of inbreeding are not a major cause of global colony losses”, says Matthew Webster, researcher at the department of Medical Biochemistry and Microbiology, Uppsala University.
Another unexpected result was that honeybees seem to be derived from an ancient lineage of cavity-nesting bees that arrived from Asia around 300,000 years ago and rapidly spread across Europe and Africa. This stands in contrast to previous research that suggests that honeybees originate from Africa.
“The evolutionary tree we constructed from genome sequences does not support an origin in Africa, this gives us new insight into how honeybees spread and became adapted to habitats across the world”, says Matthew Webster.
Hidden in the patterns of genome variation are signals that indicate large cyclical fluctuations in population size that mirror historical patterns of glaciation. This indicates that climate change has strongly impacted honeybee populations historically.
“Populations in Europe appear to have contracted during ice ages whereas African populations have expanded at those times, suggesting that environmental conditions there were more favourable”, says Matthew Webster.
The researchers also identified specific mutations in genes important in adaptation to factors such as climate and pathogens, including those involved in morphology, behaviour and innate immunity.
“The study provides new insights into evolution and genetic adaptation, and establishes a framework for investigating the biological mechanisms behind disease resistance and adaptation to climate, knowledge that could be vital for protecting honeybees in a rapidly changing world”, says Matthew Webster.
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The animal, known as Hallucigenia due to its otherworldly appearance, had been considered an ‘evolutionary misfit’ as it was not clear how it related to modern animal groups. Researchers from the University of Cambridge have discovered an important link with modern velvet worms, also known as onychophorans, a relatively small group of worm-like animals that live in tropical forests. The results are published in the advance online edition of the journal Nature.
The affinity of Hallucigenia and other contemporary ‘legged worms’, collectively known as lobopodians, has been very controversial, as a lack of clear characteristics linking them to each other or to modern animals has made it difficult to determine their evolutionary home.
What is more, early interpretations of Hallucigenia, which was first identified in the 1970s, placed it both backwards and upside-down. The spines along the creature’s back were originally thought to be legs, its legs were thought to be tentacles along its back, and its head was mistaken for its tail.
Hallucigenia lived approximately 505 million years ago during the Cambrian Explosion, a period of rapid evolution when most major animal groups first appear in the fossil record. These particular fossils come from the Burgess Shale in Canada’s Rocky Mountains, one of the richest Cambrian fossil deposits in the world.
Looking like something from science fiction, Hallucigenia had a row of rigid spines along its back, and seven or eight pairs of legs ending in claws. The animals were between five and 35 millimetres in length, and lived on the floor of the Cambrian oceans.
A new study of the creature’s claws revealed an organisation very close to those of modern velvet worms, where layers of cuticle (a hard substance similar to fingernails) are stacked one inside the other, like Russian nesting dolls. The same nesting structure can also be seen in the jaws of velvet worms, which are no more than legs modified for chewing.
“It’s often thought that modern animal groups arose fully formed during the Cambrian Explosion,” said Dr Martin Smith of the University’s Department of Earth Sciences, the paper’s lead author. “But evolution is a gradual process: today’s complex anatomies emerged step by step, one feature at a time. By deciphering ‘in-between’ fossils like Hallucigenia, we can determine how different animal groups built up their modern body plans.”
While Hallucigenia had been suspected to be an ancestor of velvet worms, definitive characteristics linking them together had been hard to come by, and their claws had never been studied in detail. Through analysing both the prehistoric and living creatures, the researchers found that claws were the connection joining them together. Cambrian fossils continue to produce new information on origins of complex animals, and the use of high-end imaging techniques and data on living organisms further allows researchers to untangle the enigmatic evolution of earliest creatures.
“An exciting outcome of this study is that it turns our current understanding of the evolutionary tree of arthropods – the group including spiders, insects and crustaceans – upside down,” said Dr Javier Ortega-Hernandez, the paper’s co-author. “Most gene-based studies suggest that arthropods and velvet worms are closely related to each other; however, our results indicate that arthropods are actually closer to water bears, or tardigrades, a group of hardy microscopic animals best known for being able to survive the vacuum of space and sub-zero temperatures – leaving velvet worms as distant cousins.”
“The peculiar claws of Hallucigenia are a smoking gun that solve a long and heated debate in evolutionary biology, and may even help to decipher other problematic Cambrian critters,” said Dr Smith.
University of Cambridge – Header Image : Hallucigenia : WikiPedia
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Before they sank to the bottom of their shallow marine habitat and were fossilized some 435 million years ago, these arthropods preyed on other denizens of the Silurian seas – although they were not exactly inconspicuous, possessing a bivalved carapace and multiple abdominal limbs. A group of researchers including LMU biologist Carolin Haug recently recognized these fossils as the oldest representatives yet discovered of an enigmatic and now extinct class of arthropods known as Thylacocephala, and assigned them to the new species Thylacares brandonensis. “Where exactly the thylacocephalans belong among the arthropods is still a matter of intense debate,” Haug says, but the new specimens shed light on the phylogenetic affinities of this problematic group of animals.
According to the authors of the study just published, certain aspects of the anatomy of T. brandonensis, together with the results of a detailed investigation of more recent specimens attributable to the group, support the hypothesis that the thylocephalans belong among the crustaceans. Moreover, the anatomy of their posteror appendages and an analysis of the organization of their muscles with the aid of fluorescence microscopy strongly suggest that they can be interpreted as a sister group of the so-called Remipedia. Remipedians, which were first described in the 1980s, are blind crustaceans found in flooded limestone caves in coastal settings in the tropics. These cave systems are typically connected to the sea via subsurface channels and are also open to the surface further inland.
“The main reason why it has been so difficult to work out the precise systematic position of thylacocephalans is that their morphology is so bizarre,” says Haug. “For a long time, researchers couldn’t even agree which end was anterior and which posterior.” Most of the specimens so far described come from strata of Jurassic age, and are therefore 200-250 million years younger than the new species.
Representatives of the group typically have unusually large compound eyes and are equipped with several paired and anteriorly located raptorial appendages, which are almost as long as the rest of the animal. This combination of characters strongly suggests that they were adapted to a predatory lifestyle. “Actually the eyes were initially not recognized as such, and instead were interpreted as stomach pouches by some researchers,” says Haug. By comparison with its spectacular descendants, the new species T. brandonensis can be described as modest and unassuming. “Representatives of this thylacocephalan species have a more ‘normal’ morphology,” says Haug, “their eyes are smaller and the raptorial appendages are shorter.”
The authors of the new study therefore conclude that, like more recent representatives of the group, T. brandonensis also earned its living as a predator, but was less highly specialized than the later forms. Consequently, the morphological specializations seen in the latter probably emerged in the course of the further evolution of the class. “It is quite possible that the extreme degree of specialization seen in specimens from the Jurassic proved to be an evolutionary dead end,” Haug suggests, “for at the close of the Cretaceous, at a time when many other groups of animals disappeared from the fossil record, Thylacocephala also became extinct.” However, we now know that these predators had previously enjoyed a successful career that lasted for more than 350 million years.
Ludwig-Maximilians-Universitaet Muenchen (LMU) – Header Image Credit : biomedcentral
In 1934, American archaeologist Nelson Glueck named one of the largest known copper production sites of the Levant “Slaves’ Hill.” This hilltop station, located deep in Israel’s Arava Valley, seemed to bear all the marks of an Iron Age slave camp — fiery furnaces, harsh desert conditions, and a massive barrier preventing escape. New evidence uncovered by Tel Aviv University archaeologists, however, overturns this entire narrative.
In the course of ongoing excavations at Timna Valley, Dr. Erez Ben-Yosef and Dr. Lidar Sapir-Hen of TAU’s Department of Archaeology and Near Eastern Cultures analyzed remnants of food eaten by copper smelters 3,000 years ago. The result of this analysis, published in the journal Antiquity, indicates that the laborers operating the furnaces were in fact skilled craftsmen who enjoyed high social status and adulation. They believe their discovery may have ramifications for similar sites across the region.
“What we found represents a general trend or reality related to metal workers in antiquity,” said Dr. Ben-Yosef. “They had a very unique role in society, and we can demonstrate this by looking at Timna.”Examining ancient leftovers
The rare arid conditions of Timna have resulted in unparalleled preservation of organic materials usually destroyed by the march of time: bones, seeds, fruits, and even fabric dating back to the 10th century B.C. Using a technique called “wet sieving,” the archaeologists found miniscule animal and fish bones, evidence of a rich and diverse diet.
“The copper smelters were given the better cuts of meat — the meatiest parts of the animals,” said Dr. Sapir-Hen. “Someone took great care to give the people working in the furnaces the best of everything. They also enjoyed fish, which must have been brought from the Mediterranean hundreds of kilometers away. This was not the diet of slaves but of highly-regarded, maybe even worshipped, craftsmen.”
Copper, used at the time to produce tools and weapons, was the most valuable resource in ancient societies. According to Dr. Ben-Yosef, the smelters needed to be well-versed in the sophisticated technology required to turn stone into usable copper. This knowledge was so advanced for the time it may have been considered magical or supernatural.
“Like oil today, copper was a source of great power,” said Dr. Ben-Yosef. “If a person had the exceptional knowledge to ‘create copper,’ it is not surprising he would have been treated well. In comparing our findings to current ethnographic accounts from Africa, we see smelters worshipped and even honored with animal sacrifices.”
Copper production is a complex operation requiring many levels of expertise. Ancient mine workers at Timna may have indeed been slaves or prisoners, because theirs was a simple task performed under severe conditions. However, the act of smelting, turning stone into metal, required an enormous amount of skill and leadership. The smelter had to build a furnace out of clay in precise dimensions, provide the right amount of oxygen and charcoal, maintain a 1,200 degree (Celsius) heat, connect bellow pipes, blow a fixed amount of air, and add an exact mixture of minerals. All told, the smelter had to manage some 30-40 variables in order to produce the coveted copper ingots.Reconstructing social diversity
According to Dr. Sapir-Hen, an expert on early complex societies, the food remains reflect the social stratification of different laborers at the site. “By studying the remains of domesticated food animals, we reveal differential access to meat that may indicate different levels of specialization among workers at the same site. This allowed us to reconstruct social diversity at the site,” said Dr. Sapir-Hen.
The remains of the wall found at the Timna site, once considered a barrier used to contain slave laborers, apparently played a different role as well. “We now know it was a wall used to defend the sophisticated technology and its most precious product — the ingot, the result of the complex copper smelting process,” said Dr. Ben-Yosef.
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Researchers at McGill University published in the journal Nature, turned to a living fish, called Polypterus, to help show what might have happened when fish first attempted to walk out of the water. Polypterus is an African fish that can breathe air, ‘walk’ on land, and looks much like those ancient fishes that evolved into tetrapods. The team of researchers raised juvenile Polypterus on land for nearly a year, with an aim to revealing how these ‘terrestrialized’ fish looked and moved differently.
“Stressful environmental conditions can often reveal otherwise cryptic anatomical and behavioural variation, a form of developmental plasticity”, says Emily Standen, a former McGill post-doctoral student who led the project, now at the University of Ottawa. “We wanted to use this mechanism to see what new anatomies and behaviours we could trigger in these fish and see if they match what we know of the fossil record.”Remarkable anatomical changes
The fish showed significant anatomical and behavioural changes. The terrestrialized fish walked more effectively by placing their fins closer to their bodies, lifted their heads higher, and kept their fins from slipping as much as fish that were raised in water. “Anatomically, their pectoral skeleton changed to became more elongate with stronger attachments across their chest, possibly to increase support during walking, and a reduced contact with the skull to potentially allow greater head/neck motion,” says Trina Du, a McGill Ph.D. student and study collaborator.
“Because many of the anatomical changes mirror the fossil record, we can hypothesize that the behavioural changes we see also reflect what may have occurred when fossil fish first walked with their fins on land”, says Hans Larsson, Canada Research Chair in Macroevolution at McGill and an Associate Professor at the Redpath Museum.Unique experiment
The terrestrialized Polypterus experiment is unique and provides new ideas for how fossil fishes may have used their fins in a terrestrial environment and what evolutionary processes were at play.
Larsson adds, “This is the first example we know of that demonstrates developmental plasticity may have facilitated a large-scale evolutionary transition, by first accessing new anatomies and behaviours that could later be genetically fixed by natural selection”.
McGill University – Header Image Credit : Photo: A. Morin, E.M. Standen, T. Du and H. Larsson
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Attaching a stone tip on to a wooden spear shaft was a significant innovation for early modern humans living around 500,000 years ago. However, it was also a costly behavior in terms of time and effort to collect, prepare and assemble the spear. Stone tips break more frequently than wooden spears, requiring more frequent replacement and upkeep, and the fragility of a broken point could necessitate multiple thrusts to an angry animal. So, why did early hunters begin to use stone-tipped spears?
To learn if there was a “wounding” advantage between using a wooden spear or a stone-tipped spear, ASU postdoctoral researcher Jayne Wilkins, doctoral student Benjamin Schoville and coauthor Kyle Brown from the University of Cape Town, conducted controlled experiments using tipped and untipped spear replications, a calibrated crossbow and ballistics gelatin. The experiments looked at the size and shape of the “wound,” penetration depth and damage done by extraction of the spear. Wilkins and Schoville are affiliated with the Institute of Human Origins, a research center of the ASU College of Liberal Arts and Sciences in the School of Human Evolution and Social Change.
Their experiments found that although tipped spears did not penetrate deeper than the untipped spears as is commonly thought, the tipped spears create wider wound cavities. These wider wound cavities would have caused more debilitating tissue damage to internal organs of animals, making hunts more successful. This is one explanation for an evolutionary advantage for tipped a spear with a stone, an innovation that may have significantly impacted the evolution of human life-history.
“Putting a fragile stone tip on a spear is risky,” said Schoville, “but we show that there are serious rewards in terms of both the size and shape of the wound created that made this innovation extremely worthwhile during our evolution.”
The authors also posit that the manufacture of the stone-tipped spears may represent the origin of new cognitive and social development in our human ancestors. Working memory (the ability to hold attention to multiple tasks in order to collect, prepare and combine different kinds of raw materials into a weapon), and constructive memory (the ability to imagine and plan for future tasks), were mental capacities required for tipped spear construction. In addition, since a stone-tipped spear is a skill likely to have been learned by being passed from generation to generation through social or group learning, stone-tipped technology is evidence of the evolutionary impact of “cumulative culture.”
The flip side of this greater human cooperation is where groups and individuals are more likely to cooperate when others have very lethal weapons—a situation still in play today.
Wine production, distribution, and consumption are thought to have played a role in the lives of those living in the Mediterranean and Near East during the Middle Bronze Age (1900-1600 BC), but little archaeological evidence about Bronze Age wine is available to support art and documentation about the role wine played during this period.
During a 2013 excavation of the Middle Bronze Age Canaanite palace in modern-day Israel, the researchers in this study found 40 large storage vessels in an enclosed room located to the west of the central courtyard.
An organic residue analysis using mass spectrometry revealed that all of the relatively uniform jars contained chemical compounds indicative of wine. The authors also detected subtle differences in the ingredients or additives within similarly shaped wine jars, including honey, storax resin, terebinth resin, cedar oil, cyperus, juniper, and possibly mint, myrtle, and cinnamon.
The researchers suggest the detection of these additives indicates that humans at the time had a sophisticated understanding of plants and skills necessary to produce a complex beverage that balanced preservation, palatability, and psychoactivity. According to the authors, these results may contribute to a greater understanding of ancient viticulture and the Canaanite palatial economy.
Andrew Koh added, “Based on the nature of the room, it was anticipated from the beginning that residue samples extracted and studied under virtually identical circumstances with minimal variability would have the potential to reveal new and significant insights from both a scientific and archaeological perspective.
We believe this study will not only change our understanding of ancient viticulture and palatial social practices, but also the manner in which we approach organic residue analysis (ORA) as an integrated, qualitative, and interdisciplinary exercise that is as field dependent as it is laboratory intensive.”
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