6 results on '"Diachronic"'
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2. Successional Pathways of Avifauna in a Shifting Mosaic Landscape: Interplay between Land Abandonment and Wildfires.
- Author
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Prodon, Roger
- Subjects
- *
SHRUBLANDS , *NUMBERS of species , *FOREST succession , *WILDLIFE conservation , *FOREST birds , *BIRD breeding , *WILDFIRE prevention , *FIREFIGHTING - Abstract
In Mediterranean hinterlands, land abandonment has led to the encroachment of woody vegetation prone to fire. The resulting alternation between vegetation closure and sudden opening modifies the composition of avifauna. We first conducted a stratified sampling of the avifauna in a grassland-to-forest gradient representing the closure of vegetation after abandonment (space-for-time substitution). We then conducted postfire diachronic sampling (up to 42 years) on stations belonging to this gradient. Mid-successional shrubland avifauna was the most radically modified after fire—ground-nesting species replacing shrub-nesting species—without significant change in species numbers. In the medium term, shrub-nesting birds widened their distribution in the landscape. While avifauna postfire successions in shrubland paralleled the spontaneous colonization of grasslands by woody vegetation, postfire forest successions were distinguished by the persistence of certain forest birds, resulting in assemblages of high diversity in which open-habitat birds coexisted with forest species. This temporary vegetation–avifauna mismatch results from both the reluctance of open-habitat birds to enter burned areas because of numerous snags, and the site fidelity of breeding birds. This inertia mitigates the short-term impact of fire. In the long term, spontaneous or postfire successions converge towards a homogeneous forest avifauna, to the detriment of open-habitat species of high conservation value. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
3. Heterochrony as Diachronically Modified Cell-Cell Interactions.
- Author
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Torday, John S.
- Subjects
- *
HETEROCHRONY (Biology) , *CELL communication , *PROTEIN receptors - Abstract
Heterochrony is an enabling concept in evolution theory that metaphorically captures the mechanism of biologic change due to mechanisms of growth and development. The spatio-temporal patterns of morphogenesis are determined by cell-to-cell signaling mediated by specific soluble growth factors and their cognate receptors on nearby cells of different germline origins. Subsequently, down-stream production of second messengers generates patterns of form and function. Environmental upheavals such as Romer's hypothesized drying up of bodies of water globally caused the vertebrate water-land transition. That transition caused physiologic stress, modifying cell-cell signaling to generate terrestrial adaptations of the skeleton, lung, skin, kidney and brain. These tissue-specific remodeling events occurred as a result of the duplication of the Parathyroid Hormone-related Protein Receptor (PTHrPR) gene, expressed in mesodermal fibroblasts in close proximity to ubiquitously expressed endodermal PTHrP, amplifying this signaling pathway. Examples of how and why PTHrPR amplification affected the ontogeny, phylogeny, physiology and pathophysiology of the lung are used to substantiate and further our understanding through insights to the heterochronic mechanisms of evolution, such as the fish swim bladder evolving into the vertebrate lung, interrelated by such functional homologies as surfactant and mechanotransduction. Instead of the conventional description of this phenomenon, lung evolution can now be understood as adaptive changes in the cellular-molecular signaling mechanisms underlying its ontogeny and phylogeny. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
4. Homeostasis as the Mechanism of Evolution.
- Author
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Torday, John S.
- Subjects
- *
BIOLOGICAL evolution , *HOMEOSTASIS , *EMBRYOLOGY - Abstract
Homeostasis is conventionally thought of merely as a synchronic (same time) servo-mechanism that maintains the status quo for organismal physiology. However, when seen from the perspective of developmental physiology, homeostasis is a robust, dynamic, intergenerational, diachronic (across-time) mechanism for the maintenance, perpetuation and modification of physiologic structure and function. The integral relationships generated by cell-cell signaling for the mechanisms of embryogenesis, physiology and repair provide the needed insight to the scale-free universality of the homeostatic principle, offering a novel opportunity for a Systems approach to Biology. Starting with the inception of life itself, with the advent of reproduction during meiosis and mitosis, moving forward both ontogenetically and phylogenetically through the evolutionary steps involved in adaptation to an ever-changing environment, Biology and Evolution Theory need no longer default to teleology. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
5. Homeostasis as the Mechanism of Evolution
- Author
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John S. Torday
- Subjects
teleology ,1.1 Normal biological development and functioning ,Biology ,phylogeny ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,0302 clinical medicine ,Underpinning research ,evolution ,homeostasis ,lcsh:QH301-705.5 ,development ,030304 developmental biology ,Genetics ,0303 health sciences ,General Immunology and Microbiology ,epigenetics ,Mechanism (biology) ,Biological Sciences ,Hypothesis ,Structure and function ,Evolution theory ,lcsh:Biology (General) ,Teleology ,diachronic ,embryogenesis ,Developmental physiology ,Adaptation ,General Agricultural and Biological Sciences ,Cell-cell signaling ,cell-cell signaling ,Neuroscience ,030217 neurology & neurosurgery ,Homeostasis ,scale-free - Abstract
Homeostasis is conventionally thought of merely as a synchronic (same time) servo-mechanism that maintains the status quo for organismal physiology. However, when seen from the perspective of developmental physiology, homeostasis is a robust, dynamic, intergenerational, diachronic (across-time) mechanism for the maintenance, perpetuation and modification of physiologic structure and function. The integral relationships generated by cell-cell signaling for the mechanisms of embryogenesis, physiology and repair provide the needed insight to the scale-free universality of the homeostatic principle, offering a novel opportunity for a Systems approach to Biology. Starting with the inception of life itself, with the advent of reproduction during meiosis and mitosis, moving forward both ontogenetically and phylogenetically through the evolutionary steps involved in adaptation to an ever-changing environment, Biology and Evolution Theory need no longer default to teleology.
- Published
- 2015
6. Does Conversion to Organic Farming Impact Vineyards Yield? A Diachronic Study in Southeastern France.
- Author
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Merot, Anne and Smits, Nathalie
- Subjects
- *
ORGANIC farming , *PEST control , *GRAPE yields , *VINEYARDS , *DISEASE management , *CONSUMPTION (Economics) - Abstract
Given the need to reduce pesticide use and rising consumer demand for healthy food, organic vineyard areas have increased since 2000. Converting to organic farming requires numerous changes in pest and disease management, fertilization and weeding techniques. These changes can lead to difficulties in sustaining yields. Some studies have highlighted higher yields in conventional farming than in organic agriculture, but knowledge on yield dynamics during conversion is lacking. A set of 26 plots, under conventional management and in conversion to organic farming, were monitored from 2013 to 2016 in southern France throughout the three-year conversion phase to investigate the dynamics of grape yield and yield components. The survey showed that the yield and yield components remained similar levels as in conventional farming from the third year of conversion. However, the first two years of conversion were a transitional and less successful period during which yield and yield components decreased. Based on the in-depth analysis of the yield components, we have put forwards hypotheses on the processes at play and technical advice that could support winegrowers as they convert to organic farming. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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