Consumer Life History and Demography in Dynamic Environments
Date
2014-09-30
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Abstract
Individual demographic performance is the outcome of a complex interaction between a set of physiological rules predetermined at a genetic level, the individual, and a particular context, the environment. Both are highly dynamical entities. The environment varies in response to many deterministic and stochastic forces, and individuals respond to their environment as a function of their own internal conditions. My thesis combines empirical and theoretical works on consumer-resource systems in order to study how genetic and environmental factors interact to generate patterns of phenotypic expression and assess their effects on resulting ecological and evolutionary dynamics.
I first present methods for carrying out sensitivity analysis of dynamic energy budget models. These techniques are then used to study how the feedback loop between consumer and resource dynamics affects individual life-history and emerging demographical patterns. Thirdly, I present the results of large manipulative experiments on Daphnia-algae systems aiming at characterizing how the combined effect of genetic variation and environmental fluctuations affect the population demographic patterns and their underlying energetic basis. The genomic response of individuals was further characterized through microarray experiments. Finally, I integrate some of these results within a simplified model framework to draw general implications for the dynamics of ecological systems.
Sensitivity analysis reveals that including the effect of the environmental feedback drastically alters the predictions that are made on the patterns of expression in individual life history, and tends to buffer genotypic variation. Experimentations decouple this environmental feedback to reveal that the demography of the different clones is impacted in a different way by environmental food fluctuations. This result arises because the relation between individual energetics and food density is qualitatively affected by dynamic variation in the food environment. The genomic analysis supports these results and also emphasizes the importance of consumer-resource interactions for the functioning of biological organisms, as up to 84% of the Daphnia genome was found to respond to variation in food conditions.
All the results of this thesis converge to highlight the fact that dynamical aspects in the environment significantly affect patterns of genetic expression at both the individual and population level.
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Ecology
Citation
Richard, R. (2014). Consumer Life History and Demography in Dynamic Environments (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/25433