نتایج جستجو برای: fossil record
تعداد نتایج: 121933 فیلتر نتایج به سال:
One way the effects of both ecology and environment on species can be observed in the fossil record is as changes in geographical distribution and range size. The prevalence of competitive interactions and species replacements in the fossil record has long been investigated and many evolutionary perspectives, including those of Darwin, have emphasized the importance of competitive interactions ...
The fossil record of early vertebrates has been influential in elucidating the evolutionary assembly of the gnathostome bodyplan. Understanding of the timing and tempo of vertebrate innovations remains, however, mired in a literal reading of the fossil record. Early jawless vertebrates (ostracoderms) exhibit restriction to shallow-water environments. The distribution of their stratigraphic occu...
Vestigial structures occur at both the anatomical and molecular levels, but studies documenting the co-occurrence of morphological degeneration in the fossil record and molecular decay in the genome are rare. Here, we use morphology, the fossil record, and phylogenetics to predict the occurrence of "molecular fossils" of the enamelin (ENAM) gene in four different orders of placental mammals (Tu...
Volume 2, The Earth system: biological and ecological dimensions of global environmental change, pp 297–301
Evidence of fossil Peronosporomycetes has been slow to accumulate. In this review various fossils historically assigmed to the Peronosporomycets are dicussed briefly and an explanation is provided as to why the fossil record of this grouop has remained inconsistent. In recent year there has been several new reports of fossil peronosporomycetes based on structurally preserved oogonium-antheridiu...
Diversification rates are estimated from phylogenies, typically without fossils, except in paleontological studies. By nature, rate estimations depend heavily on the time data provided in phylogenies, which are divergence times and (when used) fossil ages. Among these temporal data, fossil ages are by far the most precisely known (divergence times are inferences calibrated with fossils). We pro...
Insects provide a severe challenge for Darwinian evolution. In contrast with the vertebrate fossil record, for example, where only bones are available, evolutionary speculation can run wild, but the exquisite detail of fossil insects has produced virtual silence on this front. A review of the insect fossil record literature reveals a complete lack of evidence for the evolution of insects and ot...
BACKGROUND Caviidae is a diverse group of caviomorph rodents that is broadly distributed in South America and is divided into three highly divergent extant lineages: Caviinae (cavies), Dolichotinae (maras), and Hydrochoerinae (capybaras). The fossil record of Caviidae is only abundant and diverse since the late Miocene. Caviids belongs to Cavioidea sensu stricto (Cavioidea s.s.) that also inclu...
A fossil tarantula (Araneae: Mygalomorphae: Theraphosidae) is described from an exuvium in Tertiary (Miocene) Chiapas amber, Simojovel region, Chiapas State, Mexico. It is difficult to assign it further taxonomically, but it is the first mygalomorph recorded from Chiapas amber and only the second unequivocal record of a fossil theraphosid. With a carapace length of ca. 0.9 cm and an estimated l...
The fossil record provides a powerful basis for analyzing the controlling factors and impact of biological evolution over a wide range of temporal and spatial scales and in the context of an evolving Earth. An increasingly interdisciplinary paleontology has begun to formulate the next generation of questions, drawing on a wealth of new data, and on methodological advances ranging from high-reso...
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