News Article | November 29, 2016
KNOXVILLE -- Learning between human social groups may be key to sustaining the environment, according to a new study that uses mathematical modeling to understand what factors most influence societies to conserve natural resources. Researchers at the National Institute for Mathematical and Biological Synthesis (NIMBioS) developed a model to simulate how societies with different social structures and institutions manage their resources. In the model, true to form, societies that over-exploited their environment went extinct, and societies survived when individuals cooperated by limiting their personal consumption. But the researchers went further: they wanted to understand what factors influenced individual cooperation, enabling the societies to survive. The key appeared to be social groups. In the model, societies that were divided into multiple groups were four times more likely to conserve their resources and survive than societies that had no sub-group divisions. "Usually, we assume that everyone has to cooperate to save environmental resources, but what we found was that sustainable use of resources emerged more when societies were broken up into multiple groups, like states in the United States, or countries in Europe," said lead author Tim Waring, an associate professor at the Mitchell Center for Sustainability Solutions and the School of Economics at the University of Maine. The model showed that societies broken up into multiple groups evolved better institutions for managing their resources because each group could learn from the successes and failures of the others. "This between-group learning means that behaviors and institutions that help groups survive can spread among groups," Waring explained. Waring cited the example of the United Nation's first climate change talks at the Rio Earth Summit in 1992, which took a top-down approach and was viewed largely as a failure, whereas the Paris climate change meeting in 2015 was successful in part because it emerged from the grassroots level, initially amongst smaller groups. "Part of the problem is that cooperation is harder to grow in larger groups, but when smaller groups learn to cooperate and be sustainable, their practices can spread," Waring said. The paper was published in Ecological Economics and is available at http://dx. The research was conducted as a part of a theoretical working group, which Waring co-organized, at NIMBioS. The National Institute for Mathematical and Biological Synthesis is an NSF-supported center that brings together researchers from around the world to collaborate across disciplinary boundaries to investigate solutions to basic and applied problems in the life sciences. Citation: Waring TM, Goff SH, Smaldino PE. 2016. The coevolution of economic institutions and sustainable consumption via cultural group selection. Ecological Economics. [Online] The National Institute for Mathematical and Biological Synthesis is an NSF-supported center that brings together researchers from around the world to collaborate across disciplinary boundaries to investigate solutions to basic and applied problems in the life sciences.
Fitzpatrick B.M.,University of Tennessee at Knoxville |
Fitzpatrick B.M.,National Institute for Mathematical and Biological Synthesis
BMC Evolutionary Biology | Year: 2012
Background: Hybridization, genetic mixture of distinct populations, gives rise to myriad recombinant genotypes. Characterizing the genomic composition of hybrids is critical for studies of hybrid zone dynamics, inheritance of traits, and consequences of hybridization for evolution and conservation. Hybrid genomes are often summarized either by an estimate of the proportion of alleles coming from each ancestral population or classification into discrete categories like F1, F2, backcross, or merely "hybrid" vs. "pure". In most cases, it is not realistic to classify individuals into the restricted set of classes produced in the first two generations of admixture. However, the continuous ancestry index misses an important dimension of the genotype. Joint consideration of ancestry together with interclass heterozygosity (proportion of loci with alleles from both ancestral populations) captures all of the information in the discrete classification without the unrealistic assumption that only two generations of admixture have transpired. Methods. I describe a maximum likelihood method for joint estimation of ancestry and interclass heterozygosity. I present two worked examples illustrating the value of the approach for describing variation among hybrid populations and evaluating the validity of the assumption underlying discrete classification. Results: Naively classifying natural hybrids into the standard six line cross categories can be misleading, and false classification can be a serious problem for datasets with few molecular markers. My analysis underscores previous work showing that many (50 or more) ancestry informative markers are needed to avoid erroneous classification. Conclusion: Although classification of hybrids might often be misleading, valuable inferences can be obtained by focusing directly on distributions of ancestry and heterozygosity. Estimating and visualizing the joint distribution of ancestry and interclass heterozygosity is an effective way to compare the genetic structure of hybrid populations and these estimates can be used in classic quantitative genetic methods for assessing additive, dominant, and epistatic genetic effects on hybrid phenotypes and fitness. The methods are implemented in a freely available package "HIest" for the R statistical software. © 2012 Fitzpatrick; licensee BioMed Central Ltd.
News Article | December 16, 2015
An adult Gelada monkey plays with a juvenile. A new special issue of Adaptive Behavior examines the evolution and origin of play via mathematical and computational approaches. Credit: Elisabetta Palagi Research on the evolution and function of play at the National Institute for Mathematical and Biological Synthesis (NIMBioS) has culminated in a special issue of the journal Adaptive Behavior. The papers represent the first systematic use of computational and mathematical models to investigate the theoretical and empirical origins of play. In a series of meetings from 2011 to 2013, the NIMBioS Working Group on Play, Evolution and Sociality brought together mathematicians, anthropologists, zoologists, neuroscientists, ecologists, psychologists and other top experts to examine play as a window into cognitive evolution and the rules of sociality. Until the Working Group was established, the field lacked a mathematical and computational approaches for understanding how play evolves. Using mathematical tools, the group aimed to uncover factors predicting the dynamics, occurrence and trajectory of play in the animal kingdom, as well as explore the ecological, psychological and life history factors that facilitate and maintain play. The six papers in the special issue include: Explore further: UT professor defines play, discovers even turtles need recess More information: The full special issue can be found at adb.sagepub.com/content/23/6.toc
News Article | November 10, 2015
Being a leader entails lots of skills, knowledge and attitude to be able to support team members and peers effectively. Researchers from the National Institute for Mathematical and Biological Synthesis (NIMBIOS) embarked on a study to find out the patterns of leadership existing among small-scale mammalian species, including animals and humans. The authors surprisingly found clues on being an effective leader among the members of the animal kingdom. Leadership is an essential point of research among social and biological sciences; however, efforts to combine these within or across disciplines are scarce. Although theories of evolution may help aid such synthesis, further components are still required in order for a strong comparative model to ensue. Difference in leadership can be determined via numerous factors such as ways on how to become a leader (emergence), the scope of leadership (distribution), the amount of power that leaders use on subordinates (power), whether or not the leader gain more or less than followers (relative benefit) and the manner with which a leader of one domain can lead another group (generality). "A comparative framework based on these dimensions can reveal commonalities and differences among leaders in mammalian societies, including human societies," the authors wrote. The authors of the study performed their investigation by studying leadership evidences in four disciplines including movement, conflict mediation within groups, food gathering and group interactions between groups. The domains reviewed were said to enable the researchers to classify leadership patterns in the five factors that differentiate leadership as discussed above. The results of the analysis showed that leadership is commonly attained as humans and animals undergo experiences. However, exceptions to this finding point out to spotted hyenas and Nootka, which gained leadership by inheritance rather than through experiences. Should human leaders be compared to other mammals, the power of the former may not be as robust at all. In other mammalian species, leadership is more likely intensified, with leaders that use more power over followers. Corresponding author Jennifer Smith of Mills College in Oakland, California said that the similarities possibly emulate shared cognitive processes influencing dominance, subordination, compact creation and decision-making. Meanwhile, the difference may partially be justified by humans' inclination to take on more special social positions. "Even in the least complex human societies, the scale of collective action is greater and presumably more critical for survival and reproduction than in most other mammalian societies," Smith said. The study was published online in the journal Trends in Ecology & Evolution on Friday, Nov. 6.
News Article | June 7, 2016
Find Out How Computer Technology Is Changing The World In some parts of the United States, extracting natural gas from shale rock has a negative effect both below and above ground. Such effects of gas extraction on the environment include degrading freshwater systems, displacing rare species, eroding soil and fragmenting fragile habitats. Unfortunately, it has long been established that minimizing the effects of drilling may come at a greater cost for developers. Now, a new algorithm developed by scientists may help reduce environmental impact. Thanks to the algorithm, a team of scientists led by Austin Milt of the National Institute for Mathematical and Biological Synthesis (NIMBioS) have found that the additional costs for developers are actually even smaller than the savings made to the environment. This suggests that the benefits far outweigh the harm. The new NIMBioS study indicates that on average, a 20 percent increase in development costs could cut surface-level environment impact by more than a third. Milt and his colleagues developed an algorithm to quantify the costs of environmental impacts. The main goal was to find out how the construction of additional shale gas sites would help them achieve this plan. The novel algorithm helped them design the construction of access roads, well pads, and pipelines at 84 sites in Pennsylvania, which was chosen to represent shale energy development in the U.S. because of its 10,000 drilled wells. The new algorithm plans infrastructure the same way most developers do, adhering to strict regulations and practices. The only difference is that the primary goal for each plan is to protect the environment, researchers said. In the end, Milt and his team found that while developers can indeed reduce environmental impact at a small cost, the outcomes were dependent on the characteristics of the shale gas site. Several of the effects were easier to address and therefore less costly to avoid than others. For instance, a large portion of the impacts on the environment could be prevented by steering development away from areas considered as habitats for endangered and rare species. Because the results rely on site conditions, scientists say the right approach to regulate infrastructure development is not a one-size-fits-all approach. Milt says there are other, more flexible alternatives that would minimize impacts on the environment at the same or less cost. Details of the study are published in the journal Conservation Biology. © 2016 Tech Times, All rights reserved. Do not reproduce without permission.
News Article | January 25, 2016
Collecting and re-examining more than 5,600 estimates of ocean microbial cell and virus populations recorded over the past 25 years, researchers have found that viral populations vary dramatically from location to location, and at differing depths in the sea. The study highlights another source of uncertainty governing climate models and other biogeochemical measures. "What was surprising was that there was not a constant relationship, as people had assumed, between the number of microbial cells and the number of viruses," said Joshua Weitz, an associate professor in the School of Biology at the Georgia Institute of Technology and one of the paper's two senior co-authors. "Because viruses are parasites, it was assumed that their number would vary linearly with the number of microbes. We found that the ratio does not remain constant, but decreases systematically as the number of microbes increases." The research, which involved authors from 14 different institutions, was initiated as part of a working group from the National Institute for Mathematical and Biological Synthesis (NIMBioS), which is supported by the National Science Foundation. The research was completed with additional support from the Burroughs Wellcome Fund and the Simons Foundation. The research was co-led by Steven Wilhelm, a professor of microbiology at the University of Tennessee, Knoxville. In the datasets examined by the researchers, the ratio of viruses to microbes varied from approximately 1 to 1 and 150 to 1 in surface waters, and from 5 to 1 and 75 to 1 in the deeper ocean. For years, scientists had utilized a baseline ratio of 10 to 1 - ten times more viruses than microbes—which may not adequately represent conditions in many marine ecosystems. "A marine environment with 100-fold more viruses than microbes may have very different rates of microbial recycling than an environment with far fewer viruses," said Weitz. "Our study really begins to challenge the notion of a uniform ecosystem role for viruses." A key target for viruses are cyanobacteria—marine microorganisms that obtain their energy through photosynthesis in a process that takes carbon out of the atmosphere. What happens to the carbon these tiny organisms remove may be determined by whether they are eaten by larger grazing creatures—or die from viral infections. When these cyanobacteria die from infections, their carbon is likely to remain in the top of the water column, where it can nourish other microorganisms. If they are eaten by larger creatures, their carbon is likely to sink into the deeper ocean as the grazers die or excrete the carbon in in their feces. "Viruses have a role in shunting some of the carbon away from the deep ocean and keeping it in the surface ocean," said Wilhelm. "Quantifying the strength of the viral shunt remains a vital issue." Influenza and measles come to mind when most people think of viruses, but the bulk of world's viruses actually infect microorganisms. Estimates suggest that a single liter of seawater typically contain more than ten billion viruses. To better understand this population, the researchers conducted a meta-analysis of the microbial and virus abundance data that had been collected over multiple decades, including datasets collected by many of the co-authors whose laboratories are based in the United States, Canada and Europe. The data had been obtained using a variety of techniques, including epifluorescence microscopy and flow cytometry. By combining data collected by 11 different research groups, the researchers created a big picture from many smaller ones. The statistical relationships between viruses and microbial cells, analyzed by first-author Charles Wigington from Georgia Tech and second-author Derek Sonderegger from Northern Arizona University, show the range of variation. The available data provides information about the abundance of viral particles, not their diversity. Viruses are selective in the microbes the target, meaning the true rates of infection require a renewed focus on virus-microbe infection networks. "Future research should focus on examining the relationship between ocean microorganisms and viruses at the scale of relevant interactions," said Weitz, "And more ocean surveys are needed to fill in the many blanks for this critical part of the carbon cycle. Indeed, virus infections of microbes could change the flux of carbon and nutrients on a global scale." Explore further: Decade-long study reveals recurring patterns of viruses in the open ocean More information: Re-examination of the relationship between marine virus and microbial cell abundances, DOI: 10.1038/nmicrobiol.2015.24
News Article | January 6, 2016
A study from the National Institute for Mathematical and Biological Synthesis develops new methods to detect the onset of critical transitions in infectious disease epidemics, such as malaria. "Billions of dollars are spent annually on various interventions to stop diseases like malaria, and the investments have made a difference. But, government and public health agencies need the will to continue making these investments after the initial reduction of cases has occurred. The question becomes at what point does the continued investment pay off?" said lead author and NIMBioS postdoctoral fellow Suzanne O'Regan. "Quantitative evaluation tools can go a long way in helping governments and philanthropic organizations choose the optimal level of investment in control and elimination activities after the number of cases slows down." The method developed in the study, which was published in the journal Theoretical Ecology, identifies the critical slowing-down period in human cases of the mosquito-borne parasite that causes malaria, suggesting that eradicating the disease could be anticipated even without a full of understanding of the underlying mechanisms that are causing the slow down. The researchers used a mathematical model to study the gradual implementation of four common tactics used to control and eliminate malaria: using bed nets to reduce the number of mosquito bites, spraying indoor insecticides to shorten mosquito lifespans, administering drugs that reduce the human infectious period, and eliminating mosquito habitat. The analysis focuses on malaria, but the findings are relevant to other mosquito-borne infections, such as yellow fever, also endemic in some parts of the world. "Our work suggests that online algorithms for detecting changes in leading indicators may be achievable and could eventually be developed, possibly aiding sustainment of the gains made by elimination programs," O'Regan said. Explore further: Virus evolution differs by species of mosquito carrier
Zefferman M.R.,National Institute for Mathematical and Biological Synthesis |
Mathew S.,Arizona State University
Evolutionary Anthropology | Year: 2015
When humans wage war, it is not unusual for battlefields to be strewn with dead warriors. These warriors typically were men in their reproductive prime who, had they not died in battle, might have gone on to father more children. Typically, they are also genetically unrelated to one another. We know of no other animal species in which reproductively capable, genetically unrelated individuals risk their lives in this manner. Because the immense private costs borne by individual warriors create benefits that are shared widely by others in their group, warfare is a stark evolutionary puzzle that is difficult to explain. Although several scholars have posited models of the evolution of human warfare, these models do not adequately explain how humans solve the problem of collective action in warfare at the evolutionarily novel scale of hundreds of genetically unrelated individuals. We propose that group-structured cultural selection explains this phenomenon. © 2015 Wiley Periodicals, Inc.
News Article | November 6, 2015
As the American media continues to buzz over who is more or less likely to secure the Republican and Democratic nominations for U.S. President, researchers in the journal Trends in Ecology & Evolution review some interesting perspectives on the nature of leadership. The experts from a wide range of disciplines examined patterns of leadership in a set of small-scale mammalian societies, including humans and other social mammals such as elephants and meerkats. "While previous work has typically started with the premise that leadership is somehow intrinsically different or more complex in humans than in other mammals, we started without a perceived notion about whether this should be the case," said Jennifer Smith of Mills College in Oakland, California. "By approaching this problem with an open mind and by developing comparable measures to compare vastly different societies, we revealed more similarities than previously appreciated between leadership in humans and non-humans." Chimpanzees travel together, capuchins cooperate in fights, and spotted hyenas cooperate in hunting, but the common ways that leaders promote those collective actions has remained mysterious, Smith and her colleagues say. It wasn't clear just how much human leaders living in small-scale societies have in common with those in other mammalian societies either. To consider this issue, a group of biologists, anthropologists, mathematicians, and psychologists gathered at the National Institute for Mathematical and Biological Synthesis. These experts reviewed the evidence for leadership in four domains—movement, food acquisition, within-group conflict mediation, and between-group interactions—to categorize patterns of leadership in five dimensions: distribution across individuals, emergence (achieved versus inherited), power, relative payoff to leadership, and generality across domains. Despite what those ongoing presidential primaries might lead one to think, the analysis by the scientific experts finds that leadership is generally achieved as individuals gain experience, in both humans and non-humans. There are notable exceptions to this rule: leadership is inherited rather than gained through experience among spotted hyenas and the Nootka, a Native Canadian tribe on the northwest coast of North America. In comparison to other mammal species, human leaders aren't so powerful after all. Leadership amongst other mammalian species tends to be more concentrated, with leaders that wield more power over the group. Smith says the similarities probably reflect shared cognitive mechanisms governing dominance and subordination, alliance formation, and decision-making—humans are mammals after all. The differences may be explained in part by humans' tendency to take on more specialized roles within society. "Even in the least complex human societies, the scale of collective action is greater and presumably more critical for survival and reproduction than in most other mammalian societies," Smith said. The researchers now plan to further quantify the various dimensions identified in the new work. There's still plenty more to learn. "As ambitious as our task was, we have only just scraped the surface in characterizing leadership across mammalian societies and some of the most exciting aspects of the project are still yet to come as biologists and anthropologists implement our novel scheme for additional taxa and societies," Smith said. Explore further: Spotted hyenas can increase survival rates by hunting alone More information: Trends in Ecology & Evolution, Smith et al.: "Leadership in Mammalian Societies: Emergence, Distribution, Power, and Payoff" dx.doi.org/10.1016/j.tree.2015.09.013
News Article | November 30, 2015
The tiger salamander might provide some clues. A new study from a team of scientistsfrom the National Institute for Mathematical and Biological Synthesis (NIMBioS) andClemson University evaluates what mechanisms drive diversity in bone function,providing new insight into the evolution of how tetrapods—the earliest four-leggedvertebrate animals—took their first steps on land. In order to understand the biology of fossilized animals, researchers often turn to livinganimals with similarities that help model how extinct animals moved. Salamanders areparticularly good organisms for studying how locomotion onto land evolved, as theiranatomy and ecology is similar to the earliest tetrapods. Bones must regularly withstand a variety of different forces, or "loads," from both thecontraction of muscles and from interaction with the environment. Limb bones inparticular must accommodate some of the highest forces. Fossil records suggest thatthe forelimb and hind limb may have had different functions for walking on land, but thespecific mechanisms that contributed to these differences are less known. Theresearchers wanted to test what factors could have driven diversity in skeletal design inthe evolution of early tetrapods. The mechanics of bone loading in the salamanders were tested in a variety of ways,including filming the salamanders as they walked across a custom-built platform thatmeasured forces on the limb bones. A comparison of forelimbs and hind limbs and ananalysis of limb joints were conducted. Mathematical models were used to evaluate howthe limb bones were able to withstand the physical demands of walking on land. To assure a good test, salamanders that turned, stopped or fell on the platform orwalked diagonally, for example, were excluded from the study.The study found that the forelimbs, compared to the hind limbs, had lower yield stresses,higher mechanical hardness, and a greater ability to withstand loads higher than normal. "These results offer new perspectives in modeling how tetrapods may have taken theirfirst steps onto land, by considering the unique contributions of both the forelimbs andhind limbs, " said lead author Sandy Kawano, a postdoctoral fellow at NIMBioS. Explore further: A small step for lungfish, a big step for the evolution of walking More information: S. M. Kawano et al. Comparative limb bone loading in the humerus and femur of the tiger salamander Ambystoma tigrinum: testing the 'mixed-chain' hypothesis for skeletal safety factors, Journal of Experimental Biology (2015). DOI: 10.1242/jeb.125799