RESUMEN
This study statistically assesses the relationship between the planktic foraminiferal long-term diversity pattern (~170 Ma to Recent) and four major paleobiological diversification models: (i) the 'Red Queen' (Van Valen, 1973; Raup et al., 1973), (ii) the turnover-pulse (Vrba, 1985; Brett and Baird, 1995), (iii) the diversity-equilibrium (Sepkoski, 1978; Rosenzweig, 1995), and (iv) the 'complicated logistic growth' (Alroy, 2010a). Our results suggest that the long-term standing diversity pattern and the interplay between origination and extinction rates displayed by this group do not correspond to the first three models, but can be more readily explained by the fourth scenario. Consequently, these patterns are likely controlled by a combination of planktic foraminiferal interspecific competition as well as various environmental changes such as marine global temperatures that could impacted the niches within the upper mixed layer within the oceans. Moreover, as other global long-term patterns have been interpreted as reflecting 'complicated logistic growth', this study further suggests that the interplay between abiotic and biotic factors are fundamental elements influencing the evolutionary processes over the extensive history of the biota.
Este estudio evalúa estadísticamente la relación entre el patrón de diversidad global de los foraminíferos planctónicos en el largo plazo (~170 Ma al Reciente) y los cuatro modelos de diversificación propuestos desde la rama de la paleobiología: (i) "Reina Roja" (Van Valen, 1973; Raup et al., 1973), (ii) remplazo pausado (Vrba, 1985; Brett y Baird, 1995), (iii) diversidad en equilibrio (Sepkoski, 1978; Rosenzweig, 1995), y (iv) el "crecimiento logístico complicado" (Alroy, 2010a). Nuestros resultados sugieren que la forma de este patrón global de diversidad y la inter-relación entre las tasas de extinción y originación de este grupo no corresponden con los primeros tres modelos anteriormente citados. Sin embargo, estos pueden ser explicados bajo el cuarto escenario. Consecuentemente, las dinámicas de diversidad (i.e. patrón de diversidad y tasas de extinción y originación) de este grupo posiblemente son controladas por la combinación de la competencia interespecífica de los foraminíferos planctónicos y varios cambios ambientales tales como temperaturas globales marinas que pudieron impactar el número de nichos dentro de la capa superior de los océanos. Además, otros patrones globales de diversidad en el largo plazo han sido interpretados como el reflejo del modelo de crecimiento logístico complicado, lo que sugiere que la relación entre factores abióticos y bióticos tiene un carácter fundamental en los procesos evolutivos que han sucedido a lo largo de la historia de la vida.
RESUMEN
This paper presents some of the recent challenges to the Modern Synthesis of evolutionary theory, which has dominated evolutionary thinking for the last sixty years. The focus of the paper is the challenge of soft inheritance - the idea that variations that arise during development can be inherited. There is ample evidence showing that phenotypic variations that are independent of variations in DNA sequence, and targeted DNA changes that are guided by epigenetic control systems, are important sources of hereditary variation, and hence can contribute to evolutionary changes. Furthermore, under certain conditions, the mechanisms underlying epigenetic inheritance can also lead to saltational changes that reorganize the epigenome. These discoveries are clearly incompatible with the tenets of the Modern Synthesis, which denied any significant role for Lamarckian and saltational processes. In view of the data that support soft inheritance, as well as other challenges to the Modern Synthesis, it is concluded that that synthesis no longer offers a satisfactory theoretical framework for evolutionary biology.
RESUMEN
Catfishes constitute a highly diversified, cosmopolitan group that represents about one third of all freshwater fishes and is one of the most diverse Vertebrate taxa. The detailed study of the Siluriformes can, thus, provide useful data, and illustrative examples, for broader discussions on general phylogeny and macroevolution. In this short note I briefly expose how the study of this remarkably diverse group of fishes reveals an example of highly homoplasic, complex 'mosaic' morphological evolution.
Los peces gato constituyen un grupo cosmopolita ampliamente diversificado, el cual representa cerca de un tercio de todos los peces de agua dulce, y es uno de los taxones más diversos de vertebrados. El detallado estudio de los Siluriformes puede, de esta forma, proveer datos útiles y ejemplos ilustrativos para amplias discusiones de filogenia general y macroevolución. En esta comunicación expondré brevemente cómo el estudio de este grupo notoriamente diverso revela un ejemplo de amplia homoplasia y un complejo «mosaico¼ de evolución morfológica.
Asunto(s)
Animales , Filogenia , Bagres , Evolución BiológicaRESUMEN
Among the comparative approaches that have been used to understand the patterns of morphologicaldiversification, those related to the detection and evaluation of large-scale evolutionary trends have recentlybeen highlighted. A new method known as the analysis of skewness (ANSKEW) allows partitioning betweenthe passive and driven trends associated with the random occupation of a bounded morphological spaceand a single morphological attractor, respectively. This partitioning provides a better understanding of therelative role of processes that occur at distinct hierarchical levels associated with the macroevolutionarytrends of morphological diversification. In this paper, we used this new approach to understand the patternsof morphological diversification in Erodiscini (Coleoptera, Curculionidae, Otidocephalinae) beetles. Whengenera were used as subclades, ANSKEW revealed that 19.9% of the body size variation in the Erodiscini wasattributable to driven trends, i.e., a morphological attractor, whereas 80.1% of the variation was attributableto the occupation of different adaptive zones by distinct subclades (a passive process), with the passivecomponents being significant (based on 5,000 bootstrap samples). This simple approach to partitioningprovided insights into the intrinsic dynamics of body size evolution in this group without the need to considerexplicit phylogenetic structures. Such analyses could provide a starting point for further evaluation of adaptivevariation at multiple hierarchical levels and of the processes underlying the relationship between variationin body size and other ecological, physiological and behavioral aspects.