scholarly journals Ontogenetic Allometry and Cranial Shape Diversification Among Human Populations From South America

2011 ◽  
Vol 294 (11) ◽  
pp. 1864-1874 ◽  
Author(s):  
Paula N. Gonzalez ◽  
S. Ivan Perez ◽  
Valeria Bernal
Keyword(s):  
South America ◽  
Human Populations ◽  
Ontogenetic Allometry ◽  
Cranial Shape

scholarly journals Ontogenetic allometry constrains cranial shape of the head-first burrowing worm lizardCynisca leucura(Squamata: Amphisbaenidae)

2016 ◽  
Vol 277 (9) ◽  
pp. 1159-1167 ◽  
Author(s):  
Christy A. Hipsley ◽  
Marc-Nicolas Rentinck ◽  
Mark-Oliver Rödel ◽  
Johannes Müller
Keyword(s):  
Ontogenetic Allometry ◽  
Cranial Shape

Were human-introduced diseases the responsible for Pleistocene-Holocene megafaunal extinctions? First evidence from South America

The Holocene ◽  
2020 ◽  
pp. 095968362098167
Author(s):  
Alberto E Pérez ◽  
Federico L Agnolin
Keyword(s):  
South America ◽  
Late Pleistocene ◽  
Fasciola Hepatica ◽  
Indirect Evidence ◽  
Local Extinction ◽  
Human Populations ◽  
Human Being ◽  
Key Factor ◽  
Definite Host

Diverse hypotheses have been proposed with the aim to explain the extinction of Late Pleistocene/Holocene mammals, including the Megafauna from America. Some authors support that human being was the direct responsible of extinction by means of intensive hunting, as proposed by the “blitzkrieg” or overkilling hypothesis. However, evidence is not conclusive. As is well known by biologists, exotic diseases may play an important role in local extinction of diverse vertebrates. On this basis, some speculated that the arrival of man may also have introduced new diseases that may have played an important role on native mammals, especially megafaunal populations, probably constituting a key factor on their extinction. Recent findings of the parasite Fasciola hepatica in endemic deer from Holocene sites in Patagonia (and also probably from camelids in Peru) previous to Hispanic colonization constitute indirect evidence that may sustain this hypothesis. Because one of the main definite host of this parasite are humans, this potential disease may have been introduced by human populations as hosts and then disperse through the entire continent, as evidenced by the finding of Fasciola hepatica in Patagonia. Its presence in endemic deer and camelids previous to Hispanic colonization, reinforces the proposal that human-related diseases may have played some role in Late Pleistocene extinction of large native mammals.

scholarly journals Widespread population decline in South America correlates with mid-Holocene climate change

2018 ◽  
Author(s):  
Philip Riris ◽  
Manuel Arroyo-Kalin
Keyword(s):  
Climate Change ◽  
South America ◽  
Large Scale ◽  
Climatic Variability ◽  
Population Decline ◽  
Plant Management ◽  
Human Populations ◽  
Resource Base ◽  
Radiocarbon Dates ◽  
Middle Holocene

Quantifying the impacts of climate change on prehistoric demography is crucial for understanding the adaptive pathways taken by human populations. Archaeologists across South America have pointed to patterns of regional abandonment during the Middle Holocene (8200 to 4200 cal BP) as evidence of sensitivity to shifts in hydroclimate over this period. We develop a unified approach to investigate demography and climate in South America and aim to clarify the extent to which evidence of local anthropic responses can be generalised to large-scale trends. We achieve this by integrating archaeological radiocarbon data and palaeoclimatic time series to show that population decline occurred coeval with the transition to the initial mid-Holocene across South America. Through the analysis of radiocarbon dates with Monte Carlo methods, we find multiple, sustained phases of downturn associated to periods of high climatic variability. A likely driver of the duration and severity of demographic turnover is the frequency of exceptional climatic events, rather than the absolute magnitude of change. Unpredictable levels of tropical precipitation had sustained negative impacts on pre-Columbian populations lasting until at least 6000 cal BP, after which recovery is evident. Our results support the inference that a demographic regime shift in the second half of the Middle Holocene were coeval with cultural practices surrounding Neotropical plant management and early cultivation, possibly acting as buffers when the wild resource base was in flux.

scholarly journals conservation of freshwater and euryhaline elasmobranchs: a review

2005 ◽  
Vol 85 (5) ◽  
pp. 1049-1073 ◽  
Author(s):  
r. aidan martin
Keyword(s):  
South America ◽  
Conservation Biology ◽  
Life Histories ◽  
Significant Risk ◽  
Trophic Levels ◽  
Published Data ◽  
Human Populations ◽  
Geographic Ranges ◽  
Freshwater Habitats ◽  
Anthropogenic Threats

published data on the diversity, life history, ecology, and status of freshwater and euryhaline elasmobranchs was reviewed in the context of anthropogenic threats and principles of conservation biology. at least 171 species of elasmobranch, representing 68 genera and 34 families, are recorded from fresh or estuarine waters. of these, over half are marginal in estuaries, less than one-tenth are euryhaline, and one-fifth are obligate in fresh water. obligate freshwater elasmobranchs are dominated by myliobatoid stingrays, of which two-thirds are potamotrygonids endemic to atlantic drainages of south america. freshwater and euryhaline elasmobranchs adhere to strongly k-selected life histories and feed at high trophic levels, similar to those of their marine relatives. however, freshwater and euryhaline elasmobranchs are also subject to habitat constraints, notably more limited volume and physicochemical variability than the ocean, that may render them more vulnerable than marine elasmobranchs to the effects of human activities. the greatest diversity and abundance of freshwater and euryhaline elasmobranchs occur in tropical countries with enormous and rapidly increasing human populations, notably south america, west africa, and south-east asia. knowledge of the biology, distribution, ecology, and status of freshwater and euryhaline elasmobranchs is frustrated by unresolved taxonomic problems, which are briefly summarized. to clarify selected issues in the conservation of freshwater and euryhaline elasmobranchs, special attention is given to sharks of the genus glyphis, pristids, and potamotrygonids. to foster live release when possible as well as prevent discard of specimens and loss of data, an illustrated key to differentiate carcharhinus from glyphis sharks is provided. obligate freshwater elasmobranchs with limited geographic ranges are deemed most vulnerable to extinction, but euryhaline elasmobranchs that require access to the sea to breed are also at significant risk. based on the foregoing data and principles of conservation biology, suggested action plans for the conservation of freshwater and euryhaline elasmobranchs and the conservation of freshwater habitats are provided.

scholarly journals The Chilean Strawberry (Fragaria chiloensis): Over 1000 Years of Domestication

HortScience ◽  
2013 ◽  
Vol 48 (4) ◽  
pp. 418-421 ◽  
Author(s):  
Chad E. Finn ◽  
Jorge B. Retamales ◽  
Gustavo A. Lobos ◽  
James F. Hancock
Keyword(s):  
South America ◽  
Fruit Size ◽  
Human Populations ◽  
Western Coast ◽  
Breeding Programs ◽  
Land Races ◽  
South Central ◽  
Fragaria Chiloensis ◽  
White Form ◽  
The University

The cultivated strawberry of South America, the octoploid Fragaria chiloensis, has a long and interesting history. Although the origin of the species in Chile has not been completely determined, it may have been introduced from North America by birds. After making landfall in Chile, the species spread from the coast into the mountains eventually developing four biotypes. At least two native peoples, the Mapuche, between Rio Bío-Bío and south–central Chile, and the Picunche, between Rio Itata and Rio Bío-Bío, began the domestication process. Although white- and red-fruited forms were domesticated, the white form (likely because of its fruit size) may have been preferred because the red-fruited types are not mentioned as frequently in the literature. At the time of the Spanish invasion of Chile, F. chiloensis was widely grown in small garden plots. Under the Spanish rule, larger plantings, first of 1 to 2 ha and later of many hectares, were grown. As the Spanish continued their exploration and conquest of South America, they carried F. chiloensis with them up the western coast to Perú and Ecuador. For many years these scattered plantings were the source of fresh fruit for the burgeoning human populations. The cultivated F. ×ananassa was introduced in Chile ≈1830 but F. chiloensis was still preferentially grown. In the early 1900s, a large canning industry emerged serving hundreds of acres of F. chiloensis. By the 1950s, F. ×ananassa began to predominate and the rise in importance of the University of California and European-developed cultivars displaced much of the traditional F. chiloensis production. An increased awareness of this vast native Chilean genetic resource arose in the 1980s and 1990s. Scientists at the Universidad de Talca, associated with USDA-ARS Plant Exploration Office-sponsored trips to Chile, and with El Instituto de Investigaciones Agropecuarias–Cauquenes in Chile have collected and characterized germplasm that represents not only tremendous diversity, but captures many of the land races that have been developed. This germplasm has been used in small commercial plantings (0.1 to 0.3 ha) and in breeding programs to further develop F. chiloensis commercial cultivars. A small but vibrant community of small growers, particularly in Chile and Ecuador, produce the land races for commercial sale in local markets. Approximately 30 to 40 ha of open-field plantings are cultivated in Chile with yields averaging ≈3 to 4 tons/ha. The selected F. chiloensis genotypes and collected clones from the wild have served as a valuable source of germplasm in modern breeding programs and the development of new cultivars with the white color and aromatic flavor typical of some of the traditional selections well underway.

Past human populations and landscapes in the Fuegian Archipelago, southernmost South America

2019 ◽  
Vol 92 (2) ◽  
pp. 304-322
Author(s):  
Ivana Laura Ozán ◽  
María Cecilia Pallo
Keyword(s):  
South America ◽  
Probability Distributions ◽  
Volcanic Eruptions ◽  
Human Populations ◽  
Human Occupation ◽  
Land Use Patterns ◽  
Long Distance ◽  
Beagle Channel ◽  
Environmental Deterioration ◽  
European Colonization

AbstractThis contribution discusses possible relationships between human populations and Holocene environmental deterioration phenomena (cold/arid pulses and volcanic eruptions) in the Fuegian Archipelago (South America), based on summed probability distributions of archaeological dates, paleoenvironmental information, geospatial data, and archaeological evidence. During the first millennia after peopling, only the Hudson (ca. 7700 cal yr BP) and the first Monte Burney (ca. 8600 cal yr BP) eruptions might have played a role in human dispersion. Particularly, a more intense human occupation around the Beagle Channel and long-distance interactions are proposed as risk-buffer strategies related to the Hudson eruption. A cooling phase and a demographic growth at ca. 5500 cal yr BP might have favored more dispersed spatial occupations and a subsistence diversification in the Beagle Channel. In the northern steppes, the second Monte Burney eruption (ca. 4300 cal yr BP) and an arid episode (ca. 2600 cal yr BP) are proposed as the main triggers for changes in land-use patterns, long-network interactions, and subsistence strategies. Even though occupation changes in the Fuegian Archipelago coexist with environmental deterioration episodes after 1500 cal yr BP, demographic processes and the European colonization most likely explain this trend. Similarities between the steppe/ecotone and forest occupation curves suggest common behavioral patterns across the Holocene.

scholarly journals Evolutionary Dynamics of Oropouche Virus in South America

2019 ◽  
Vol 94 (5) ◽  
Author(s):  
Bernardo Gutierrez ◽  
Emma L. Wise ◽  
Steven T. Pullan ◽  
Christopher H. Logue ◽  
Thomas A. Bowden ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
South America ◽  
Amazon Basin ◽  
Evolutionary Dynamics ◽  
Yellow Fever Virus ◽  
Surface Proteins ◽  
Human Populations ◽  
Evolutionary Processes ◽  
Public Health Burden ◽  
Evolutionary Forces

ABSTRACT The Amazon basin is home to numerous arthropod-borne viral pathogens that cause febrile disease in humans. Among these, Oropouche orthobunyavirus (OROV) is a relatively understudied member of the genus Orthobunyavirus, family Peribunyaviridae, that causes periodic outbreaks in human populations in Brazil and other South American countries. Although several studies have described the genetic diversity of the virus, the evolutionary processes that shape the OROV genome remain poorly understood. Here, we present a comprehensive study of the genomic dynamics of OROV that encompasses phylogenetic analysis, evolutionary rate estimates, inference of natural selective pressures, recombination and reassortment, and structural analysis of OROV variants. Our study includes all available published sequences, as well as a set of new OROV genome sequences obtained from patients in Ecuador, representing the first set of genomes from this country. Our results show differing evolutionary processes on the three segments that comprise the viral genome. We infer differing times of the most recent common ancestors of the genome segments and propose that this can be explained by cryptic reassortment. We also present the discovery of previously unobserved putative N-linked glycosylation sites, as well as codons that evolve under positive selection on the viral surface proteins, and discuss the potential role of these features in the evolution of OROV through a combined phylogenetic and structural approach. IMPORTANCE The emergence and reemergence of pathogens such as Zika virus, chikungunya virus, and yellow fever virus have drawn attention toward other cocirculating arboviruses in South America. Oropouche virus (OROV) is a poorly studied pathogen responsible for over a dozen outbreaks since the early 1960s and represents a public health burden to countries such as Brazil, Panama, and Peru. OROV is likely underreported since its symptomatology can be easily confounded with other febrile illnesses (e.g., dengue fever and leptospirosis) and point-of-care testing for the virus is still uncommon. With limited data, there is a need to optimize the information currently available. Analysis of OROV genomes can help us understand how the virus circulates in nature and can reveal the evolutionary forces that shape the genetic diversity of the virus, which has implications for molecular diagnostics and the design of potential vaccines.

scholarly journals HTLV in South America: Origins of a silent ancient human infection

2020 ◽  
Vol 6 (2) ◽  
Author(s):  
Ricardo Ishak ◽  
Marluísa de Oliveira Guimarães Ishak ◽  
Vânia Nakauth Azevedo ◽  
Luiz Fernando Almeida Machado ◽  
Izaura Maria Cayres Vallinoto ◽  
...  
Keyword(s):  
South America ◽  
Molecular Subtype ◽  
Clinical Manifestations ◽  
Human Infection ◽  
Human Migration ◽  
Indigenous Populations ◽  
Aggressive Lymphoma ◽  
Human Populations ◽  
Sexually Transmitted ◽  
T Lymphotropic Virus

Abstract The description of the first human retrovirus, human T-lymphotropic virus 1 (HTLV-1), was soon associated with an aggressive lymphoma and a chronic inflammatory neurodegenerative disease. Later, other associated clinical manifestations were described, affecting diverse target organs in the human body and showing the enormous burden carried by the virus and the associated diseases. The epidemiology of HTLV-1 and HTLV-2 showed that they were largely distributed around the world, although it is possible to locate geographical areas with pockets of low and very high prevalence and incidence. Aboriginal Australians and indigenous peoples of Brazil are examples of the large spread of HTLV-1 and HTLV-2, respectively. The epidemiological link of both situations is their occurrence among isolated, epidemiologically closed or semi-closed communities. The origin of the viruses in South America shows two different branches with distinct timing of entry. HTLV-1 made its probable entrance in a more recent route through the east coast of Brazil at the beginning of the slave trade from the African continent, starting in the 16th century and lasting for more than 350 years. HTLV-2 followed the ancient route of human migration from the Asian continent, crossing the Behring Strait and then splitting in South America as the population became separated by the Andes Mountains. By that time, HTLV-2c probably arose and became isolated among the indigenous populations in the Brazilian Amazon. The study of epidemiologically closed communities of indigenous populations in Brazil allowed tracing the most likely route of entry, the generation of a new molecular subtype (HTLV-2c), the elucidation of the vertical transmission of HTLV-2, the intrafamilial aggregation of cases and the escape and spread of the virus to other areas in Brazil and abroad. Despite the burden and impact of both viruses, they are maintained as silent infections among human populations because 1, health authorities in most South American countries in which national surveillance is poor have little interest in the disease, 2, the information is commonly lost as indigenous groups do not have specific policies for HTLV and other sexually transmitted infections, and 3, health access is not feasible or properly delivered.

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