0000000000555900
AUTHOR
Miquel De Renzi
La funcionalidad, si existe, no deriva de un propósito. Una argumentación desde la biomorfodinámica y la evo-devo
RESUMENLa noción de propósito es inherente a la finalidad (adaptación, función) si se toma ésta como causa principal de las estructuras orgánicas. Éstas surgen a través del desarrollo, que tiene una causalidad propia, sin propósito con respecto al organismo adulto. El desarrollo esta canalizado y sujeto a limitaciones (constraints); por ello, no se alcanzan óptimos adaptativos en general. Sobre tales posibilidades limitadas en variabilidad actúa la selección natural; la modularidad permite combinar selectivamente aspectos independientes, pero siempre dentro de limitaciones. Pueden surgir estructuras no funcionales que llegarán –o no– a constituir exaptaciones, que serán el paso previo a tod…
Rectilinear evolution in arvicoline rodents and numerical dating of Iberian Early Pleistocene sites
Abstract Lozano-Fernandez et al. (2013a) have recently published a method intended for numerical dating of Early Pleistocene sites, which is based on the assumption of uniform, constant rate increase through time of mean lower molar tooth length of water voles ( Mimomys savini ) in a number of levels sampled in the stratigraphic sequence of Atapuerca TD site. They suggest that the regression equation obtained in this local section for site chronology on tooth size could be useful for estimating the numerical age of other localities from southwestern Europe. However, in our opinion this biostratigraphic approach has severe conceptual and methodological problems, which discourage its use as a…
Constraint and adaptation in the evolution of carnivoran skull shape
The evolutionary history of the Order Carnivora is marked by episodes of iterative evolution. Although this pattern is widely reported in different carnivoran families, the mechanisms driving the evolution of carnivoran skull morphology remain largely unexplored. In this study we use coordinate-point extended eigenshape analysis (CP-EES) to summarize aspects of skull shape in large fissiped carnivores. Results of these comparisons enable the evaluation of the role of different factors constraining the evolution of carnivoran skull design. Empirical morphospaces derived from mandible anatomy show that all hypercarnivores (i.e., those species with a diet that consists almost entirely of verte…
Has palaeontology answers for some current environmental problems?
History as an irreversible process has no role from a uniformitarian point of view in geology and palaeobiology. Contingency is another trait of history and particle palaeontology has its foundation on such principles. However, new approaches in physics and the theory of systems point out the need to consider a time arrow. Moreover, chance and necessity are interwoven in synergetics and self-organization theory and there may be some possibility of prediction. The global biota has a history resulting from a process of self-organization. A rich fossil record was produced during the Phanerozoic times and this fossil record shows us how life overcame several important crisis. A clear understand…
The giant hyena Pachycrocuta brevirostris: Modelling the bone-cracking behavior of an extinct carnivore
Abstract The giant hyena Pachycrocuta brevirostris was the largest bone-cracking carnivore that ever existed. With the mass of a lioness, it had massive limbs with shortened distal bones and a heavy, powerfully built mandible with robust, well-developed premolars. All these features reflect its adaptation for dismembering ungulate carcasses, transporting large pieces of them without dragging to the denning site and fracturing bones. This paper estimates the relative contribution of hunting and scavenging to the diet of this extinct hyena, using a combined biomechanical and taphonomic approach. Analysis of the bone-cracking behavior of P. brevirostris was based on the abundance of skeletal e…
David Malcolm Raup (1933-2015) at the starting point of a new paradigm for Palaeontology
This is a tribute to the late David Malcolm Raup, one of the major palaeontologists of the second half of the 20 th century. In addition, it is a critical review of his outstanding contributions, mainly in the field of theoretical palaeontology: quantitative modelling, the introduction of probabilistic methods in palaeontology, as well as his great imagination to use techniques from other fields, such as insurance actuary. After a general outline of his youth, I present a general depiction of the main topics of his research as a palaeobiologist: morphology, the structure of the fossil record, evolution, and extinction. He covered areas ranging from the theoretical morphology of coiled shell…
Coping between crises: Early Triassic–early Jurassic bivalve diversity dynamics
The Triassic is bounded by two of the most severe biotic crises, but nevertheless this time was, for bivalves, both a recovery and a diversification period, and a moment to fully exploit some of their evolutionary novelties. Just how and when this was achieved is analyzed in this paper, which covers Induan to Sinemurian bivalve diversity, based on a newly compiled database. Taxonomic diversity and ecospace dynamics are examined separately. Diversity and evolutionary rates were assessed, extinction selectivity was tested using a resampling algorithm, and cohort analysis was used to study extinction patterns. During the Early Triassic most bivalve genera were survivors from the Permian and th…