126 research outputs found
The Ecological And Economic Failures Of Florida\u27s Mangrove Regulatory Scheme
The mangrove ecosystem is one of the most productive and biologically diverse wetlands on Earth, providing habitats worldwide for thousands of species, including both threatened and endangered species. Although the mangroves of Florida are concurrently governed by federal, state and, often, local regulations, they are still subject to depletion through dredging and filling, and are sacrificed for private riparian rights of view. At the foundation6 of mangrove depletion is the failure of the Florida Legislature and the Florida Department of Environmental Protection (DEP) to fully account for the values served by the mangrove ecosystem in dredge and fill permitting and under the Mangrove Trimming and Preservation Act ( Mangrove Act ). This article will briefly identify the use and nonuse values served by the mangrove ecosystem, examine the real societal cost of dredging or trimming a mangrove under the current legal structure in Florida, and propose adjustments to account for the loss incurred by society when a mangrove is dredged or trimmed
The Ecological And Economic Failures Of Florida\u27s Mangrove Regulatory Scheme
The mangrove ecosystem is one of the most productive and biologically diverse wetlands on Earth, providing habitats worldwide for thousands of species, including both threatened and endangered species. Although the mangroves of Florida are concurrently governed by federal, state and, often, local regulations, they are still subject to depletion through dredging and filling, and are sacrificed for private riparian rights of view. At the foundation6 of mangrove depletion is the failure of the Florida Legislature and the Florida Department of Environmental Protection (DEP) to fully account for the values served by the mangrove ecosystem in dredge and fill permitting and under the Mangrove Trimming and Preservation Act ( Mangrove Act ). This article will briefly identify the use and nonuse values served by the mangrove ecosystem, examine the real societal cost of dredging or trimming a mangrove under the current legal structure in Florida, and propose adjustments to account for the loss incurred by society when a mangrove is dredged or trimmed
Australopithecus afarensis endocasts suggest ape-like brain organization and prolonged brain growth
Human brains are three times larger, are organized differently, and mature for a longer period of time than those of our closest living relatives, the chimpanzees. Together, these characteristics are important for human cognition and social behavior, but their evolutionary origins remain unclear. To study brain growth and organization in the hominin species Australopithecus afarensis more than 3 million years ago, we scanned eight fossil crania using conventional and synchrotron computed tomography. We inferred key features of brain organization from endocranial imprints and explored the pattern of brain growth by combining new endocranial volume estimates with narrow age at death estimates for two infants. Contrary to previous claims, sulcal imprints reveal an ape-like brain organization and no features derived toward humans. A comparison of infant to adult endocranial volumes indicates protracted brain growth in A. afarensis, likely critical for the evolution of a long period of childhood learning in hominins
Neurocranium versus Face: A Morphometric Approach with Classical Anthropometric Variables for Characterizing Patterns of Cranial Integration in Extant Hominoids and Extinct Hominins
The relative importance of the two main cranial complexes, the neurocranium and the splanchnocranium, has been examined in the five species of extant hominoids and in a huge sample of extinct hominins using six standard craniometric variables that measure the length, width and height of each cranial module. Factor analysis and two-block partial least squares were used for establishing the major patterns of developmental and evolutionary integration between both cranial modules. The results obtained show that all extant hominoids (including the anatomically modern humans) share a conserved pattern of developmental integration, a result that agrees with previous studies. The pattern of evolutionary integration between both cranial modules in australopiths runs in parallel to developmental integration. In contrast, the pattern of evolutionary and developmental integration of the species of the genus Homo is the opposite, which is probably the consequence of distinctive selective regimes for both hominin groups.JAPC, JMJA and PP received fundings from Ministerio de Ciencia e Innovación, Gobierno de España (http://www.idi.mineco.gob.es), project CGL2011-30334, and Consejería de Economía, Innovación, Ciencia y Empleo, Junta de Andalucía, España (http://www.juntadeandalucia.es/organismos/economiainnovacioncienciayempleo.html), project P11-HUM-7248 and Research Groups RNM-146 and HUM-607
Extraordinary Biomass-Burning Episode and Impact Winter Triggered by the Younger Dryas Cosmic Impact ∼12,800 Years Ago. 2. Lake, Marine, and Terrestrial Sediments
Part 1 of this study investigated evidence of biomass burning in global ice records, and here we continue to test the
hypothesis that an impact event at the Younger Dryas boundary (YDB) caused an anomalously intense episode of
biomass burning at ∼12.8 ka on a multicontinental scale (North and South America, Europe, and Asia). Quantitative
analyses of charcoal and soot records from 152 lakes, marine cores, and terrestrial sequences reveal a major peak in
biomass burning at the Younger Dryas (YD) onset that appears to be the highest during the latest Quaternary. For the
Cretaceous-Tertiary boundary (K-Pg) impact event, concentrations of soot were previously utilized to estimate the
global amount of biomass burned, and similar measurements suggest that wildfires at the YD onset rapidly consumed
∼10 million km2 of Earth’s surface, or ∼9% of Earth’s biomass, considerably more than for the K-Pg impact. Bayesian
analyses and age regressions demonstrate that ages for YDB peaks in charcoal and soot across four continents are
synchronous with the ages of an abundance peak in platinum in the Greenland Ice Sheet Project 2 (GISP2) ice core and
of the YDB impact event (12,835–12,735 cal BP). Thus, existing evidence indicates that the YDB impact event caused
an anomalously large episode of biomass burning, resulting in extensive atmospheric soot/dust loading that triggered
an “impact winter.” This, in turn, triggered abrupt YD cooling and other climate changes, reinforced by climatic
feedback mechanisms, including Arctic sea ice expansion, rerouting of North American continental runoff, and subsequent ocean circulation changes
The position of Australopithecus sediba within fossil hominin hand use diversity
The human lineage is marked by a transition in hand use, from locomotion towards increasingly dexterous manipulation, concomitant with bipedalism. The forceful precision grips used by modern humans probably evolved in the context of tool manufacture and use, but when and how many times hominin hands became principally manipulative remains unresolved. We analyse metacarpal trabecular and cortical bone, which provide insight into behaviour during an individual’s life, to demonstrate previously unrecognized diversity in hominin hand use. The metacarpals of the palm in Australopithecus sediba have trabecular morphology most like orangutans and consistent with locomotor power-grasping with the fingers, while that of the thumb is consistent with human-like manipulation. This internal morphology is the first record of behaviour consistent with a hominin that used its hand for both arboreal locomotion and human-like manipulation. This hand use is distinct from other fossil hominins in this study, including A. afarensis and A. africanus
Two interpretations of human evolution: Essentialism and Darwinism
Despite intensive studies of a large number of fossils discovered during the 20th century there is no consensus as to the interpretation of the process of hominin evolution. Some authors see as many as six genera and some 17 species, while others argue for a single lineage from Plio/Pleistocene until today. Such diversity of interpretations of the same facts indicates lack of a uniform theoretical basis underlying studies of human evolution. Debates can be resolved using basic principles of scientific inquiry - parsimony and falsification of null hypotheses. Hypothesis testing is now possible with respect to the evolution of basic hominin characteristics such as brain size, body size and the size of the dentition that have sample sizes of a few hundred individual data points each. These characters display a continuous change with time. Analyses of variance do not falsify the null hypothesis of the existence of only one species at any time - variances around regression lines on time do not differ from the variance observed in the single species of Homo sapiens - distributions of residuals are normal. Thus, splitting of the hominin lineage into coeval species can only be based on descriptive characteristics that are liable to errors of subjective judgment.Maciej Henneber
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