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Allometric scaling and metabolic ecology of microorganisms and major evolutionary transitions


Please use this identifier to cite or link to this item: http://hdl.handle.net/1928/13163

Allometric scaling and metabolic ecology of microorganisms and major evolutionary transitions

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dc.contributor.author Okie, Jordan G.
dc.date.accessioned 2011-08-31T16:09:03Z
dc.date.available 2011-08-31T16:09:03Z
dc.date.issued 2011-08-31
dc.date.submitted July 2011
dc.identifier.uri http://hdl.handle.net/1928/13163
dc.description.abstract My dissertation centers around investigating big-picture questions related to understanding the consequences of metabolism and energetics on the evolution, ecology, and physiology of life. The evolutionary transitions from prokaryotes to unicellular eukaryotes to multicellular organisms were accompanied by major innovations in metabolic design. In my first chapter, I show that the scaling of metabolic rate, population growth rate, and production efficiency with body size have changed across these transitions. Metabolic rate scales with body mass superlinearly in prokaryotes, linearly in protists, and sublinearly in metazoans, so Kleiber’s 3/4 power scaling law does not apply universally across organisms. This means that major changes in metabolic processes during the early evolution of life overcame existing physical constraints, exploited new opportunities, and imposed new constraints on organism physiology. Surface areas of physiological structures of organisms impose fundamental constraints on metabolic rate. In my second chapter, I demonstrate that organisms have a variety of options for increasing the scaling of the area of their metabolic surfaces with body sizes. I develop models and examples illustrating the role of cell membrane elaborations, mitochondria, vacuoles, vesicles, inclusions, and shape-shifting in the architectural design, evolution, and ecology of unicellular microbes. I demonstrate how these surface-area scaling adaptations have played important roles in the evolution of major biological designs of cells and the physiological ecology of organisms. In my third and final chapter, I integrate and synthesize findings from the previous two chapters with important developments in geochemistry, microbiology, and astrobiology in order to identify the fundamental physical and biological dimensions that characterize a metabolic theory of ecology of microorganisms. These dimensions are thermodynamics, chemical kinetics, physiological harshness, cell size, and levels of biological organization. I show how addressing these dimensions can inform understanding of the physical and biological factors governing the metabolic rate, growth rate, and geographic distribution of cells. I propose a unifying theory to understand how the major ecological and evolutionary transitions that led to increases in levels of organization of life, such as endosymbiosis, multicellularity, eusociality, and multi-domain complexes, influences the metabolism and growth and the metabolic scaling of these complexes. en_US
dc.description.sponsorship The Howard Hughes Medical Institute (HHMI) under the HHMI–National Institute of Biomedical Imaging and Bioengineering Interfaces Initiative (through the Program in Interdisciplinary Biological and Biomedical Science at the University of New Mexico); University of New Mexico's Biology Grove Research Scholarship and Melinda Bealmer Memorial Scholarship, University of New Mexico Student Research Allocation Committee Grants. en_US
dc.language.iso en_US en_US
dc.subject Major evolutionary transitions en_US
dc.subject Metabolic theory of ecology en_US
dc.subject Microbial ecology en_US
dc.subject Thermodynamics en_US
dc.subject Kinetics en_US
dc.subject Allometric scaling en_US
dc.subject Unicellular organisms en_US
dc.subject Body size en_US
dc.subject Cell physiological ecology en_US
dc.title Allometric scaling and metabolic ecology of microorganisms and major evolutionary transitions en_US
dc.type Dissertation en_US
dc.description.degree Biology en_US
dc.description.level Doctoral en_US
dc.description.department University of New Mexico. Biology Dept. en_US
dc.description.advisor Brown, James H.
dc.description.committee-member Michod, Richard
dc.description.committee-member Moses, Melanie
dc.description.committee-member Sinsabaugh, Robert

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