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Articles 151 - 165 of 165

Full-Text Articles in Other Ecology and Evolutionary Biology

Mechanisms For Decisions About The Future, Jeffrey R. Stevens Jan 2011

Mechanisms For Decisions About The Future, Jeffrey R. Stevens

Jeffrey Stevens Publications

Evolutionary and psychological perspectives on decision making remain largely separate endeavors. The bounded rationality approach integrates these two perspectives by focusing on simple, plausible mechanisms of decision making and the cognitive capacities needed to implement these mechanisms. Decisions about the future provide a class of decisions that lend themselves to a bounded rationality approach. Though many different mechanisms may exist for making decisions about the future, only a subset of these mechanisms actually require a representation of the future. The bounded rationality approach helps focus on the cognitive capacities and decision mechanisms that are necessary for a full understanding of …

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Ecological Effects Of Virus-Resistant Transgenic Squash, Holly R. Prendeville Nov 2010

Ecological Effects Of Virus-Resistant Transgenic Squash, Holly R. Prendeville

School of Biological Sciences: Dissertations, Theses, and Student Research

Two ecological risks associated with the use of transgenic crops include the effects of transgene products on non-target organisms and the effects of a transgene after it moves from crops into a wild plant population. In work presented here, we specifically investigate the ecological risks of virus-resistant transgenic squash. We observed pollinator behavior to determine if pollinators are affected by nontarget effects of the virus-resistant transgene. We found that pollinator behavior did differ between conventional and virus-resistant transgenic squash due to pleiotropic effects of the transgene. This difference in pollinator behavior can affect plant mating patterns, thereby affecting crop-wild hybridization …

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The Complexity-Independence Of The Origin Of Life, Radu Popa Nov 2009

The Complexity-Independence Of The Origin Of Life, Radu Popa

Systems Science Friday Noon Seminar Series

It is often stated that the macroevolution of life is driven toward increased Complexity, and indeed, biosystems situated at higher evolutionary level show higher levels of Complexity. Yet, evidence also shows that some dynamic systems evolve toward lower entropy states, and not by increasing Complexity, but by increasing Organization. Organization is a parameter with two almost orthogonal components: Order and Complexity. Hence, it is possible for a dynamic system to experience changes in Organization in ways that do not elicit changes in Complexity. Whether Order or Complexity controls changes in Organization is dictated by the capacity of a system to …

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Hamadryas Visual Identification Guide, David W. Markman Jan 2009

Hamadryas Visual Identification Guide, David W. Markman

David W Markman

No abstract provided.

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Letter From The Dean, Lalit Verma Jan 2009

Letter From The Dean, Lalit Verma

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

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In The Heat Of The Law, It's Not Just Steam: Geothermal Resources And The Impact On Thermophile Biodiversity, Donald J. Kochan, Tiffany Grant Dec 2006

In The Heat Of The Law, It's Not Just Steam: Geothermal Resources And The Impact On Thermophile Biodiversity, Donald J. Kochan, Tiffany Grant

Donald J. Kochan

Significant research has been conducted into the utilization of geothermal resources as a ‘green’ energy source. However, minimal research has been conducted into geothermal resource utilization and depletion impacts on thermophile biodiversity. Thermophiles are organisms which have adapted over millions of year to extreme temperature and chemical compositions and exist in hot springs and other geothermal resources. Their ability to withstand high temperatures makes them invaluable to scientific and medical research. Current federal and California case law classify geothermal resources as a mineral, not a water resource. Acquisition of rights to develop a geothermal resource owned or reserved by the …

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Perspectives On Reproduction And Life History In Baboons, Larissa Swedell, Steven R. Leigh Jan 2006

Perspectives On Reproduction And Life History In Baboons, Larissa Swedell, Steven R. Leigh

Publications and Research

No abstract provided.

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A Conceptual Framework For Non-Kin Food Sharing: Timing And Currency Of Benefits, Jeffrey R. Stevens, Ian C. Gilby Jan 2004

A Conceptual Framework For Non-Kin Food Sharing: Timing And Currency Of Benefits, Jeffrey R. Stevens, Ian C. Gilby

Jeffrey Stevens Publications

Many animal species, from arthropods to apes, share food. This paper presents a new framework that categorizes nonkin food sharing according to two axes: (1) the interval between sharing and receiving the benefits of sharing, and (2) the currency units in which benefits accrue to the sharer (especially food versus nonfood). Sharers can obtain immediate benefits from increased foraging efficiency, predation avoidance, mate provisioning, or manipulative mutualism. Reciprocity, trade, status enhancement and group augmentation can delay benefits. When benefits are delayed or when food is exchanged for nonfood benefits, maintaining sharing can become more difficult because animals face discounting and …

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The Selfish Nature Of Generosity: Harassment And Food Sharing In Primates, Jeffrey R. Stevens Jan 2004

The Selfish Nature Of Generosity: Harassment And Food Sharing In Primates, Jeffrey R. Stevens

Jeffrey Stevens Publications

Animals may share food to gain immediate or delayed fitness benefits. Previous studies of sharing have concentrated on delayed benefits such as reciprocity, trade and punishment. This study tests an alternative model (the harassment or sharing–under–pressure hypothesis) in which a food owner immediately benefits because sharing avoids costly harassment from a beggar. I present an experiment that varies the potential ability of the beggar to harass, and of the owner to defend the food, to examine the effects of harassment on food sharing in two primate species: chimpanzees (Pan troglodytes) and squirrel monkeys (Saimiri boliviensis). For …

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Discounting And Reciprocity In An Iterated Prisoner’S Dilemma, David W. Stephens, Colleen M. Mclinn, Jeffrey R. Stevens Jan 2002

Discounting And Reciprocity In An Iterated Prisoner’S Dilemma, David W. Stephens, Colleen M. Mclinn, Jeffrey R. Stevens

Jeffrey Stevens Publications

The Iterated Prisoner’s Dilemma (IPD) is a central paradigm in the study of animal cooperation. According to the IPD framework, repeated play (repetition) and reciprocity combine to maintain a cooperative equilibrium. However, experimental studies with animals suggest that cooperative behavior in IPDs is unstable, and some have suggested that strong preferences for immediate benefits (that is, temporal discounting) might explain the fragility of cooperative equilibria. We studied the effects of discounting and strategic reciprocity on cooperation in captive blue jays. Our results demonstrate an interaction between discounting and reciprocity. Blue jays show high stable levels of cooperation in treatments with …

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Out Of Africa: Origins Of The Taenia Tapeworms In Humans, Eric P. Hoberg, Nancy L. Alkire, Alan De Queiroz, Arlene Jones Jan 2001

Out Of Africa: Origins Of The Taenia Tapeworms In Humans, Eric P. Hoberg, Nancy L. Alkire, Alan De Queiroz, Arlene Jones

Harold W. Manter Laboratory of Parasitology: Faculty and Staff Publications

Phylogenetic and divergence date analyses indicate that the occurrence of Taenia tapeworms in humans pre-dates the development of agriculture, animal husbandry and domestication of cattle (Bos spp.) or swine (Sus scrofa) Taeniid tapeworms in Africa twice independently colonized hominids and the genus Homo prior to the origin of modern humans. Dietary and behavioural shifts, from herbivory to scavenging and carnivory, as early Homo entered the carnivore guild in the Pliocene/Pleistocene, were drivers for host switching by tapeworms to hominids from carnivores including hyaenids and felids. Parasitological data provide a unique means of elucidating the historical ecology, foraging behavior …

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Amphicyonidae, Robert Hunt Jan 1998

Amphicyonidae, Robert Hunt

University of Nebraska State Museum: Mammalogy Papers

The Amphicyonidae occur in North America from late Eocene (~40 Ma) to early late Miocene (~9 Ma), a span of 31 million years. In the North American land mammal biochronology, this diverse family extends from the Duchesnean to the end of the Clarendonian and is especially well represented in the Miocene (~5-24 Ma). In the Old World, amphicyonids survive no longer than in North America: The last European records are Vallesian (Dinotheriensande, Mainz Basin, Germany, Kuss, 1965, Tobien, 1980; Vallés-Penédes Basin, Spain, Crusafont-Pairó and Kurten, 1976), and the last representative may occur at about 9 Ma at Kohfidisch, Austria (latest …

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Taxonomic Status Of The Enigmatic Cryptotis Avia (Mammalia: Insectivora: Soricidae), With Comments On The Distribution Of The Colombian Small-Eared Shrew, Cryptotis Colombiana, Neal Woodman Oct 1996

Taxonomic Status Of The Enigmatic Cryptotis Avia (Mammalia: Insectivora: Soricidae), With Comments On The Distribution Of The Colombian Small-Eared Shrew, Cryptotis Colombiana, Neal Woodman

Neal Woodman

Cryptotis avia G. M. Allen 1823, from the Eastern Andean Cordillera of Colombia, is a small-eared shrew previously known from, at most, five specimens. Review of the holotype, consisting of an understuffed skin and a partial skull, and three potential topotypes indicates that they are refereable to Cryptotis thomasi Merriam, 1897, and C. avia should be considered ajunior synonym of that name. Cryptotis thomasi is restricted to highlands around Bogotá in the Eastern Cordillera. Another specimen previously referred to C. avia is the second known specimen of Cryptotis colombiana Woodman & Timm 1993. This second record expands the known distribution …

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Areographic Representation Of Faunal Characteristics Through A "Second Order" Relational Approach, Charles H. Smith Aug 1983

Areographic Representation Of Faunal Characteristics Through A "Second Order" Relational Approach, Charles H. Smith

DLPS Faculty Publications

Areographic analysis has traditionally depended on primary data consisting of location-specific tallies of presence or absence of given forms. In the present work, an alternate manner of representing distributions is suggested. Regional units are first established, and presence and absence of the forms under consideration in these units is noted. The relation of the biota at any given point location to all others is then established through examination of the former's characteristics of inclusion in the latter. This is accomplished by detailing regional level trends of inclusion and setting up a "second-order" distribution of associations. Two kinds of descriptive information …

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Evaporative Water Loss In Two Northwest Snakes: Pituophis Catenifer And Crotalus Viridis, Donald R. Woolery Jun 1971

Evaporative Water Loss In Two Northwest Snakes: Pituophis Catenifer And Crotalus Viridis, Donald R. Woolery

All Master's Theses

A study by Gans, Krakauer and Paganelli (1968) dealt with twenty-six species of snakes representing five families. They found that the "rate of water loss was proportional to surface area" and that water loss correlates with the aridity of the selected habitat. No comparative information resulting from the direct separation of the pulmonary and cutaneous avenues of water loss is currently available. Also, no direct comparisons of this separation in sympatric species are available. These comparisons are the basis for this study.

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