Thais (Nucella) emarginata is a common predatory gastropod of the
rocky intertidal system of western North America. It is usually found at
low tide on top of its sedentary prey, barnacles and mussels. Thais
is also highly polymorphic for shell color, and breeding of isolated
females has shown that the...
The gonadal steroids, testosterone and estradiol, are known to be important
modulators of neuronal functions and behaviors in most vertebrate species. These
steroid hormones also elicit changes in neuropeptide synthesis and secretion, alter
specific neurohormone receptor levels, and alter neuronal morphology and
electrophysiology. Many of the actions of androgens and...
Invasive species are a growing global economic and ecological problem. Invasive Indo-Pacific lionfish (Pterois spp.) are known to have extreme negative effects on coral-reef communities in the Bahamas, so understating their distribution within and among reefs, what limits their local movements, and the effects they have on native prey species...
A major goal of conservation biology is to elucidate the population genetic structure in threatened species and assess the relative importance of the evolutionary forces that shape that population genetic structure. I conducted three studies in the declining amphibian Rana cascadae to assess levels of population genetic differentiation and the...
Recent experimental and theoretical work has examined the possible genetic causes of senescence. These are reviewed, and four types of factors are found to be responsible for the evolution of senescence and age specific fecundity curves: 1. Age specific mortality schedules, 2.Density dependent factors, 3. Density independent factors, 4. Random...
This dissertation focuses on the evolutionary forces of genetic drift and gene flow in frog populations. The balance of these two forces and the force of mutation largely determine the amount of neutral genetic variation within populations as well as the degree of genetic similarity among populations. The stochastic evolutionary...