151 research outputs found
Inclusive Fitness and Differential Productivity Across the Life Course Determine Intergenerational Transfers in a Small-Scale Human Society
Transfers of resources between generations are an essential element in current models of human life-history evolution accounting for prolonged development, extended lifespan and menopause. Integrating these models with Hamilton’s theory of inclusive fitness, we predict that the interaction of biological kinship with the age-schedule of resource production should be a key driver of intergenerational transfers. In the empirical case of Tsimane’ forager–horticulturalists in Bolivian Amazonia, we provide a detailed characterization of net transfers of food according to age, sex, kinship and the net need of donors and recipients. We show that parents, grandparents and siblings provide significant net downward transfers of food across generations. We demonstrate that the extent of provisioning responds facultatively to variation in the productivity and demographic composition of families, as predicted by the theory. We hypothesize that the motivation to provide these critical transfers is a fundamental force that binds together human nuclear and extended families. The ubiquity of three-generational families in human societies may thus be a direct reflection of fundamental evolutionary constraints on an organism’s life-history and social organization
The Question of Questions: What is a Gene? Comments on Rolston and Griffths & Stotz
If the question “What is a gene?” proves to be worth asking it must be able to elicit an answer which both recognizes and address the reasons why the concept of the gene ever seemed to be something worth getting excited about in the first place as well analyzing and evaluating the latest develops in the molecular biology of DNA. Each of the preceding papers fails to do one of these and sufferrs the consequences. Where Rolston responds to the apparent failure of molecular biology to make good on the desideratum of the classical gene by veering off into fanciful talk about “cybernetic genes,” Griffiths and Stotz lose themselves in the molecular fine print and forget to ask themselves why “genes” should be of any special interst anyway
Molecular dynamics simulation of multivalent ion mediated DNA attraction
All atom molecular dynamics simulations with explicit water were done to
study the interaction between two parallel double-stranded DNA molecules in the
presence of the multivalent counterions putrescine (2+), spermidine (3+),
spermine (4+) and cobalt hexamine (3+). The inter-DNA interaction potential is
obtained with the umbrella sampling technique. The attractive force is
rationalized in terms of the formation of ion bridges, i.e. multivalent ions
which are simultaneously bound to the two opposing DNA molecules. The lifetime
of the ion bridges is short on the order of a few nanoseconds.Comment: 4 pages, 5 figures, to be published in Physical Review Letter
How khipus indicated labour contributions in an Andean village: an explanation of colour banding, seriation and ethnocategories
This research was supported by a Global Exploration Grant from the National Geographic Society (GEFNE120-14).New archival and ethnographic evidence reveals that Inka style khipus were used in the Andean community of Santiago de Anchucaya to record contributions to communal labour obligations until the 1940s. Archival testimony from the last khipu specialist in Anchucaya, supplemented by interviews with his grandson, provides the first known expert explanation for how goods, labour obligations, and social groups were indicated on Inka style Andean khipus. This evidence, combined with the analysis of Anchucaya khipus in the Museo Nacional de Arqueología, Antropología y Historia Peruana, furnishes a local model for the relationship between the two most frequent colour patterns (colour banding and seriation) that occur in khipus. In this model, colour banding is associated with individual data whilst seriation is associated with aggregated data. The archival and ethnographic evidence also explains how labour and goods were categorized in uniquely Andean ways as they were represented on khipus.PostprintPeer reviewe
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Pre-Columbian land use in the ring-ditch region of the Bolivian Amazon
The nature and extent of pre-Columbian (pre-1492 AD) human impact in Amazonia is a contentious issue. The Bolivian Amazon has yielded some of the most impressive evidence for large and complex pre-Columbian societies in the Amazon basin, yet there remains relatively little data concerning the land use of these societies over time. Palaeoecology, when integrated with archaeological
data, has the potential to fill these gaps in our knowledge. We present a 6,000-year record of anthropogenic burning, agriculture and vegetation change, from an oxbow lake located adjacent to a pre-Columbian ring-ditch in north-east Bolivia (13°15’44” S, 63°42’37” W). Human occupation around the lake site is inferred from pollen and phytoliths of maize (Zea mays L.) and macroscopic charcoal evidence of anthropogenic burning. First occupation around the lake was radiocarbon dated to ~2500 years BP. The persistence of maize in the record from ~1850 BP suggests that it was an important crop grown in the ringditch region in pre-Columbian times, and abundant macroscopic charcoal suggests that pre-Columbian land management entailed more extensive burning of the landscape than the slash-and-burn agriculture practised around the site today. The site was occupied continuously until near-modern times, although there is evidence for a decline in agricultural intensity or change in land use strategy, and possible population decline, from ~600-500 BP. The long and continuous occupation, which predates the establishment of rainforest in the region, suggests that pre-Columbian land use may have had a significant
influence on ecosystem development at this site over the last ~2000 years
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