Phenotypic plasticity of life history in the sagebrush lizard (Sceloporus graciosus) [electronic resource].

Sears, Michael Wayne.
198 p.
Local subjects:
Penn dissertations -- Biology.
Biology -- Penn dissertations.
System Details:
Mode of access: World Wide Web.
Geographically widespread species often exhibit variation in life history traits that are a result of differences in the quality and abundance of available resources. Documented body size patterns among populations of sagebrush lizards (Sceloporus graciosus) show that large body size in free-ranging lizards is associated environments that provide longer seasonal activity. It is not known whether these body size differences among populations are environmentally induced or whether they can be attributed to adaptation to local conditions. Additionally, laboratory studies have demonstrated that growth rates increase with the amount of time a lizard can maintain elevated temperatures for activity (thermal opportunity). In this study, I use a combination of field mark-recapture techniques, laboratory measurement of physiological rates, and a common environment rearing study to discern the sources of variation in body size and growth rates of sagebrush lizards. Interestingly, for three populations of sagebrush lizards in Zion National Park that are elevationally separated, the highest elevation population exhibited faster growth despite decreased thermal opportunity compared to low elevation populations. Lizards reared in a common environment exhibit similar growth under conditions of varied food and water resources, suggesting that differences in growth among populations are attributable to mainly environmental differences in resources. Furthermore, field caught, high elevation lizards were found to exhibit lower temperature-specific metabolic rates, suggesting that they may exhibit physiological acclimation that favors more efficient growth. Thus, the atypical growth pattern exhibited among populations of this species is a complex interaction between environmental variability in resources among populations and physiological acclimation to local environments.
Thesis (Ph.D. in Biology) -- University of Pennsylvania, 2001.
Source: Dissertation Abstracts International, Volume: 62-05, Section: B, page: 2213.
Supervisor: Arthur E. Dunham.
Local notes:
School code: 0175.
Dunham, Arthur E., advisor
University of Pennsylvania.
Contained In:
Dissertation Abstracts International 62-05B.
Access Restriction:
Restricted for use by site license.
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