Guy Hoelzer

University of Nevada, Reno | UNR · Department of Biology

There has been a renewed interest in the effects of genetic diversity on population-level and community-level processes. Many of these studies have found non-additive, positive effects of diversity, but these studies have rarely examined ecological mechanisms by which diverse populations increase productivity. We used the seed beetle Callosobruchus...

Biodiversity is hierarchically structured both phylogenetically and functionally. Phylogenetic hierarchy is understood as a product of branching organic evolution as described by Darwin. Ecosystem biologists understand some aspects of functional hierarchy, such as food web architecture, as a product of evolutionary ecology; but functional hierarchy...

http://www.bilalgonen.com/research/biology/Default.aspx

Wild et al. argue that the evolution of reduced virulence can be understood from the perspective of inclusive fitness, obviating the need to evoke group selection as a contributing causal factor. Although they acknowledge the mathematical equivalence of the inclusive fitness and multilevel selection approaches, they conclude that reduced virulence...

A lo largo de un período de siete años, usamos técnicas de marcado y recaptura en una población de Otus flammeolus en las montañas Zuni, New Mexico, para estimar la fidelidad de los adultos a los sitios de cría, la fidelidad de las parejas, la filopatría natal y las distancias de dispersión. También usamos huellas dactilares de ADN para examinar la...

We used DNA fingerprinting to estimate the frequency of extra-pair fertilization in the Flammulated Owl (Otus flammeolus), a socially monogamous species often found nesting in aggregations. We observed owls on 44 territories, 42 of which were located in aggregations of 3 to 10 territories with a mean nearest-neighbor distance of 539 m (± 160 m). We...

Short dispersal distance with oubreeding depression. (7.38 MB MPG)

Short dispersal distance without outbreeding depression (7.23 MB MPG)

Longer dispersal distance without outbreeding depression (6.15 MB MPG)

A commonly held view in evolutionary biology is that speciation (the emergence of genetically distinct and reproductively incompatible subpopulations) is driven by external environmental constraints, such as localized barriers to dispersal or habitat-based variation in selection pressures. We have developed a spatially explicit model of a biologica...

We present and critically examine a statistical criterion for the selection of outgroup taxa for rooting evolutionary trees. The criterion is the amount of phylogenetic signal for the ingroup when the states of the candidate outgroup taxa are assumed to be plesiomorphic relative to the ingroup for the purpose of measuring plesiomorphy content of th...

Conventional wisdom in the field of population genetics suggests that discrete boundaries between distinctive, geographically adjacent biological populations must reflect the influence of external factors, such as differential selection or a barrier to dispersal [Endler 1977]. Therefore, empirical observations of such boundaries are usually taken a...

Most evolutionary biologists cherish Darwin's theory of natural selection (NS) as the process of adaptive evolution more than 140 years after publication of his first book on the subject. However, in the past few decades the study of self-organization (SO) in complex dynamical systems has suggested that adaptation may occur through intrinsic reorga...

The study described in this chapter aimed to elucidate the historical biogeography of howler monkeys in Central America. We expected to find evidence supporting an invasion from a common ancestor of the three species proceding northward from South America into Central America, with mantled howlers and black howlers being sister species that diverge...

Over a seven-year period, we used mark-recapture in a population of Flammulated Owls (Otus flammeolus) in the Zuni Mountains, New Mexico, to estimate adult breeding-site fidelity, mate fidelity, natal philopatry, and dispersal distances. We also used DNA fingerprinting to examine the genetic population structure of Flammulated Owls among four mount...

Patterns of genetic diversity within species mark both familial relationships and subpopulation membership. They can also influence ongoing evolutionary processes. For these reasons, data on intraspecific genetic diversity are important to the study of primate social structure and historical biogeography, as well as to the design of management plan...

The phylogeographical and systematic relationships among species in the tropical marine fish genus Dascyllus were inferred using mitochondrial DNA (mtDNA) sequence data. Although our results were generally consistent with previously published phylogenies based on both morphological and mitochondrial data, our broad taxonomic and geographical sampli...