Physiological ecology of phrynosomatid lizards/ Michael Austin Robson.

Format:

Book

Manuscript

Microformat

Thesis/Dissertation

Author/Creator:

Robson, Michael Austin.

Contributor:

Dunham, Arthur Earl, advisor.

University of Pennsylvania.

Language:

English

Subjects (All):

Penn dissertations--Biology.

Biology--Penn dissertations.

Biology.

Academic Dissertations as Topic.

Medical Subjects:

Biology.

Academic Dissertations as Topic.

Local Subjects:

Penn dissertations--Biology.

Biology--Penn dissertations.

Physical Description:

xviii, 168 pages : illustrations ; 29 cm

Production:

2000.

Summary:

Locomotor performance measures may be used to explain functional links between lower level traits; i.e. morphology and higher level traits associated with fitness; i.e. survivorship or reproductive success. In a five-year longitudinal study of the banded rock lizard, Petrosaurus mearnsi , I estimated these functional links. Additionally, the physiological response to environmental variation was evaluated experimentally among three closely related species in the family Phrynosomatidae. I focused on skeletal traits that are presumed to affect locomotor performance. I used two measures of performance, maximum sprint speed and endurance, which are assumed to have a profound influence on fitness. Maximum sprint speeds attained by juveniles approached or were equivalent to adults. However, endurance increased with age. Years with high rainfall resulted in higher survivorship, of juveniles and stronger correlations between limb length, narrower pelvic characters and sprint speed. Drought years exhibited predominantly older individuals, wider pelves and greater endurance. Endurance differed significantly among age-classes and exhibited a significant age by year interaction. Longitudinal analyses revealed significant differences in both performance variables with age and through time. The response of endurance at higher or lower elevations was determined for Sceloporus occidentalis from an intermediate elevation, S. graciosus from high elevation, and S. scalaris from intermediate and high elevations. S. occidentalis and intermediate elevation S. scalaris demonstrated no response to acute differences in ambient pO2. High elevation S. graciosus and S. scalaris increased endurance at lower elevations. S. graciosus and high and intermediate elevation S. scalaris were acclimated to high, intermediate and low elevations. S. graciosus and high elevation S. scalaris increased endurance and decreased hematocrit at lower elevations. Intermediate elevation S. scalaris also increased endurance and decreased hematocrit. S. scalaris were re-evaluated at resident elevations to assess any persistent response. High elevation S. scalaris endurance returned to preacclimation levels; however, a persistent increase in endurance occurred in intermediate elevation S. scalaris. Incorporating detailed demographic information, as well as the context in which variation is measured, provides insights into the proximate and ultimate factors that influence performance.

Notes:

Adviser: Arthur Earl Dunham.

Thesis (Ph.D. in Biology) -- University of Pennsylvania, 2000.

Includes bibliographical references.

Local Notes:

University Microfilms order no.: 9989645.

OCLC:

244971807