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Full-Text Articles in Life Sciences

Patterns Of Body And Tail Length And Body Mass In Sciuridae, Virginia Hayssen Aug 2008

Patterns Of Body And Tail Length And Body Mass In Sciuridae, Virginia Hayssen

Biological Sciences: Faculty Publications

For squirrels, physical size varies with ancestry, locomotion, and sex. Body length has little variation associated with subfamilies or tribes but varies significantly among genera within tribes. Thus, patterns in body size among genera represent more recent evolutionary pressures. Flying squirrels weigh less than similarly sized tree or ground squirrels but ecological profile and ancestry are confounded for flying squirrels. Tail length has clear relationships with ecological profile in squirrels. Tail length is shorter in ground squirrels, longer in tree squirrels, and longest in flying squirrels. In addition, in arboreal squirrels, females have longer tails, relative to body length, than …


Reproduction Within Marmotine Ground Squirrels (Sciuridae, Xerinae, Marmotini): Patterns Among Genera, Virginia Hayssen Jun 2008

Reproduction Within Marmotine Ground Squirrels (Sciuridae, Xerinae, Marmotini): Patterns Among Genera, Virginia Hayssen

Biological Sciences: Faculty Publications

The sciurid tribe Marmotini has a distinctive, highly specialized reproductive profile characterized by annually produced litters of many offspring, each of small mass and fast growth rate. However, not all genera of marmotines follow the reproductive profile of the tribe. In fact, included in the tribe are squirrels with the highest and lowest energetic investment into reproduction of the entire family. Because of its large litter size, Ammospermophilus has the largest energetic investment into reproduction of nearly all squirrels. Also, Ammospermophilus is not limited to 1 litter per year. At the opposite extreme, Marmota has the smallest energetic investment into …


Revisiting A Model Of Ontogenetic Growth: Estimating Model Parameters From Theory And Data, Melanie E. Moses, Chen Hou, William H. Woodruff, Geoffrey B. West, Jeffery C. Nekola, Wenyun Zuo, James H. Brown May 2008

Revisiting A Model Of Ontogenetic Growth: Estimating Model Parameters From Theory And Data, Melanie E. Moses, Chen Hou, William H. Woodruff, Geoffrey B. West, Jeffery C. Nekola, Wenyun Zuo, James H. Brown

Biological Sciences Faculty Research & Creative Works

The ontogenetic growth model (OGM) of West et al. provides a general description of how metabolic energy is allocated between production of new biomass and maintenance of existing biomass during ontogeny. Here, we reexamine the OGM, make some minor modifications and corrections, and further evaluate its ability to account for empirical variation on rates of metabolism and biomass in vertebrates both during ontogeny and across species of varying adult body size. We show that the updated version of the model is internally consistent and is consistent with other predictions of metabolic scaling theory and empirical data. The OGM predicts not …


Reproductive Allometry And The Size-Number Trade-Off For Lizards, Eric Charnov, Robin Warne Jan 2008

Reproductive Allometry And The Size-Number Trade-Off For Lizards, Eric Charnov, Robin Warne

Biology Faculty & Staff Publications

The yearly reproductive allocation shows a 0.75 allometry with adult size across lizard species.