Life Sciences Commons^™

Estimation Of Short-Term Tag-Induced Mortality In Horseshoe Crabs Limulus Polyphemus, Jennifer Mattei, Mark Beekey, H. R. Potter, C. S. Bond, Alyssa Woronik, J. A. Roberts, K. A. Smith

Biology Faculty Publications

Horseshoe crabs Limulus Polyphemus range along the East Coast of the United States and over 150,000 of them have been marked with U.S. Fish and Wildlife Service disk tags. It has been assumed that the tags do not harm the animals and are similar to common epibionts often found on the shells of the horseshoe crabs. We investigated whether newlv tagged adult female horseshoe crabs would exhibit higher short-term mortality rates than untagged adult females. All crabs were collected from a beach in Connecticut and then were transported to a laboratory for the experiment. Tagging involved drilling a small hole …

The Response Of Banksia Roots To Change In Water Table Level In A Mediterranean-Type Environment, Caroline Canham

Theses: Doctorates and Masters

For phreatophytic plants to persist in a given habitat they need to maintain a functional connection to the water table, and the capacity for roots to respond to changes in the water table is a key aspect of this. If root growth is limited by season, plants may not be able to grow roots to adjust to changes in the water table at a particular time of the year. The redistribution of roots, particularly the capacity for roots to follow the water table down in summer and autumn months, is vital for phreatophytic plants to maintain a functional connection with …

Intracellular Invasion Of Green Algae In A Salamander Host, Ryan Kerney, Eunsoo Kim, Roger Hangater, Aaron Heiss, Cory Bishop, Brian Hall

Ryan Kerney

The association between embryos of the spotted salamander (Ambystoma maculatum) and green algae (“Oophila amblystomatis” Lamber ex Printz) has been considered an ectosymbiotic mutualism. We show here, however, that this symbiosis is more intimate than previously reported. A combination of imaging and algal 18S rDNA amplification reveals algal invasion of embryonic salamander tissues and cells during development. Algal cells are detectable from embryonic and larval Stages 26–44 through chlorophyll autofluorescence and algal 18S rDNA amplification. Algal cell ultrastructure indicates both degradation and putative encystment during the process of tissue and cellular invasion. Fewer algal cells were detected in later-stage larvae …

Symbioses Between Salamander Embryos And Green Algae, Ryan Kerney

Ryan Kerney

The symbiosis between Ambystoma maculatum (spotted salamander) embryos and green algae was initially described over 120 years ago. Algae populate the egg capsules that surround individual A. maculatum embryos, giving the intracapsular fluid a characteristic green hue. Early work established this symbiosis to be a mutualism, while subsequent studies sought to identify the material benefits of this association to both symbiont and host. These studies have shown that salamander embryos benefit from increased oxygen concentrations provided by their symbiotic algae. The algae, in turn, may benefit from ammonia excreted by the embryos. All of these early studies considered the associ- …

Molecular Anatomy Of The Developing Limb In The Coqu ́I Frog, Eleutherodactylus Coqui, Joshua Gross, Ryan Kerney, James Hanken, Clifford Tabin

Ryan Kerney

The vertebrate limb demonstrates remark- able similarity in basic organization across phylogenetically disparate groups. To gain further insight into how this mor- phological similarity is maintained in different developmental contexts, we explored the molecular anatomy of size-reduced embryos of the Puerto Rican coqu ́ı frog, Eleutherodactylus coqui. This animal demonstrates direct development, a life- history strategy marked by rapid progression from egg to adult and absence of a free-living, aquatic larva. Nonethe- less, coqu ́ı exhibits a basal anuran limb structure, with four toes on the forelimb and five toes on the hind limb. We in- vestigated the extent to …

Plant-Animal Interactions, W. Abrahamson, T. Taylor

Warren G. Abrahamson, II

No abstract provided.

Levels Of Biological Organization And The Origin Of Novelty, Brian Hall, Ryan Kerney

Ryan Kerney

The concept of novelty in evolutionary biology pertains to multiple tiers of biological organization from behavioral and morphological changes to changes at the molecular level. Identifying novel features requires assessments of similarity (homology and homoplasy) of relationships (phylogenetic history) and of shared developmental and genetic pathways or networks. After a brief discussion of how novelty is used in recent literature, we discuss whether the evolutionary approach to homology and homoplasy initially formulated by Lankester in the 19th century informs our understanding of novelty today. We then discuss six examples of morphological features described in the recent literature as novelties, and …

Calibrating Divergence Times On Species Tree Versus Gene Trees: Implications For Speciation History Of Aphelocoma Jays, John Mccormack, Joseph Heled, Kathleen Delaney, A. Peterson, L. Knowles

John E. McCormack

Estimates of the timing of divergence are central to testing the underlying causes of speciation. Relaxed molecular clocks and fossil calibration have improved these estimates; however, these advances are implemented in the context of gene trees, which can overestimate divergence times. Here we couple recent innovations for dating speciation events with the analytical power of species trees, where multilocus data are considered in a coalescent context. Divergence times are estimated in the bird genus Aphelocoma to test whether speciation in these jays coincided with mountain uplift or glacial cycles. Gene trees and species trees show general agreement that diversification began …

Embryonic Staging Table For A Direct- Developing Salamander, Plethodon Cinereus (Plethodontidae), Ryan Kerney

Ryan Kerney

This work presents a refined staging table for the direct-developing red-backed salamander Plethodon cinereus, which is based on the incom- plete staging system of James Norman Dent (J Morphol 1942; 71:577– 601). This common species from eastern North America is a member of the species-rich lungless salamander family Plethodontidae. The stag- ing table presented here covers several stages omitted by Dent and reveals novel developmental features of P. cinereus embryos. These include putative Leydig cells and open gill clefts, which are found in lar- vae of metamorphosing species but were previously reported as absent in direct-developing Plethodon. Other features found …

Adaptation As Process: The Future Of Darwinism And The Legacy Of Theodosius Dobzhansky, David Depew

David J Depew

Conceptions of adaptation have varied in the history of genetic Darwinism depending on whether what is taken to be focal is the process of adaptation, adapted states of populations, or discrete adaptations in individual organisms. I argue that Theodosius Dobzhansky’s view of adaptation as a dynamical process contrasts with so-called “adaptationist” views of natural selection figured as “design-without-a-designer” of relatively discrete, enumerable adaptations. Correlated with these respectively process and product oriented approaches to adaptive natural selection are divergent pictures of organisms themselves as developmental wholes or as “bundles” of adaptations. While even process versions of genetical Darwinism are insufficiently sensitive …

Q & A: Frederick Cohan, Frederick M. Cohan

Frederick M. Cohan

No abstract provided.

A Preliminary Study Of Heteromeles Arbutifolia Fruit Morphology At Ballona Wetlands And Temescal Canyon, Los Angeles, California, Victor D. Carmona

Victor D. Carmona-Galindo

Heteromeles arbutifolia, or the California holly, is an evergreen shrub native to chaparral habitats of Southern California that fruits from November to January. Fruit species morphology has been shown to be a good indicator of habitat quality among other plants. The variation in fruit morphologies was examined for the native plant at two diverse Southern California sites, a wetland and a canyon. California Holly fruits had a significantly greater volume in Ballona Wetlands than at Temescal Canyon (Z=4.367, P<0.001), as well as a significantly greater variance in Ballona Wetlands than at Temescal Canyon (F=2.357, P=0.02). The production of fruits with larger and more variable volumes in Ballona Wetlands may be a response to the presence of urban influences and environmental contaminants. As the reproductive structure, fruit morphology may be a good indicator of how habitat stress influences reproductive success.

A New Species Of Marsupial Frog (Anura: Hemiphractidae: Gastrotheca) From The Río Abiseo National Park In Peru, Edgar Lehr, Alessandro Catenazzi

Edgar Lehr

We describe a new species of Gastrotheca from the Río Abiseo National Park of the San Martín Region in the Andes of northern Peru. The description is based on a series of 29 specimens that were collected between 1989 and 1999 at two localities (Pampa del Cuy, Alpamachay) in the wet puna of the national park between 3380 and 3470 m elevation. The new species has a snout–vent length of 46.9–57.7 mm (53.5 ± 3.0) in females (n = 21), and 35.3–43.8 mm (41.6 ± 3.2) in males (n  =  6). In life, the dorsum is pale grayish brown with …

Influence Of Molecular Resolution On Sequence-Based Discovery Of Ecological Diversity Among Synechococcus Populations In An Alkaline Siliceous Hot Spring Microbial Mat, Melanie C. Melendrez, R. K. Lange, Frederick M. Cohan, David M. Ward

Frederick M. Cohan

No abstract provided.

Are Species Cohesive?—A View From Bacteriology, Frederick M. Cohan

Frederick M. Cohan

No abstract provided.

A Theory-Based Pragmatism For Discovering And Classifying Newly Divergent Bacterial Species, Sarah Kopac, Frederick M. Cohan

Frederick M. Cohan

No abstract provided.

Mariska Leunissen, Explanation And Teleology In Aristotle’S Science Of Nature, David J. Depew

David J Depew

No abstract provided.

Mountain Treelines: A Roadmap For Research Orientation, George P. Malanson

George P Malanson

For over 100 years, mountain treelines have been the subject of varied research endeavors and remain a strong area of investigation. The purpose of this paper is to examine aspects of the epistemology of mountain treeline research—that is, to investigate how knowledge on treelines has been acquired and the changes in knowledge acquisition over time, through a review of fundamental questions and approaches. The questions treeline researchers have raised and continue to raise have undoubtedly directed the current state of knowledge. A continuing, fundamental emphasis has centered on seeking the general cause of mountain treelines, thus seeking an answer to …

Locomotor Loading Mechanics In The Hindlimbs Of Tegu Lizards (Tupinambis Merianae): Comparative And Evolutionary Implications, K. Megan Sheffield, Michael T. Butcher, S. Katharine Shugart, Jennifer C. Gander, Richard W. Blob

Megan Sheffield

Skeletal elements are usually able to withstand several times their usual load before they yield, and this ratio is known as the bone’s safety factor. Limited studies on amphibians and non-avian reptiles have shown that they have much higher limb bone safety factors than birds and mammals. It has been hypothesized that this difference is related to the difference in posture between upright birds and mammals and sprawling ectotherms; however, limb bone loading data from a wider range of sprawling species are needed in order to determine whether the higher safety factors seen in amphibians and non-avian reptiles are ancestral …

Relationship Between Soil Sodium Concentration And Plant Height In Salicornia Virginica In The Ballona Wetlands In Los Angeles, California, Victor D. Carmona

Victor D. Carmona-Galindo

Previous studies have shown a positive relationship between biomass of the common wetland species of the halophyte, Salicornia virginica, and salinity (Callaway et al. 1998). Our research aims to implement a new technique that is less invasive than measuring total plant biomass which involves uprooting the plant. Instead, we have chosen to study the use of plant height as an indicator of sodium content in surrounding soils. Our hypothesis is that as plant height of S. virginica increases, there will be greater sodium content present in their corresponding soils. We found that plant heights had a significantly greater variation at …

Testing Radio Transmitter Attachment Techniques On Chicks Of Galliforms, Victoria Dreitz, Lauri Baeten, Tracy Davis, Margaret Riordan

Victoria Dreitz

No abstract provided.

Loading Mechanics Of The Femur In Tiger Salamanders (Ambystoma Tigrinum) During Terrestrial Locomotion, K. Megan Sheffield, Richard W. Blob

Megan Sheffield

Salamanders are often used as representatives of the basal tetrapod body plan in functional studies, but little is known about the loads experienced by their limb bones during locomotion. Although salamanders’ slow walking speeds might lead to low locomotor forces and limb bone stresses similar to those of non-avian reptiles, their highly sprawled posture combined with relatively small limb bones could produce elevated limb bone stresses closer to those of avian and mammalian species. This study evaluates the loads on the femur of the tiger salamander (Ambystoma tigrinum) during terrestrial locomotion using three- dimensional measurements of the ground reaction force …

Q&A: Frederick Cohan

Frederick M. Cohan

No abstract provided.

Lake Mead National Recreation Area Monitoring And Evaluation Of Sensitive Wildlife: Quarterly Progress Report, Period Ending December 31, 2010, Margaret N. Rees

Wildlife Monitoring

Project 1. Relict Leopard Frog Monitoring, Management, and Research

• Final milestones and deliverables for this project were completed this quarter.
• Fall monitoring surveys were completed at all sites.
• Habitat actions to improve breeding pools were conducted at one site.
• Data and associated metadata were compiled and quality assured.
• Final and annual reports were written and submitted in required formats for Clark County

and the Relict Leopard Frog Conservation Team.

Project 2. Bald Eagle Winter Monitoring and Evaluation

• This project was previously completed and all associated deliverables met.
• Efforts were provided this quarter in support of the 2011 winter count.

Project …

Oregon Aspen Project, Forest Restoration Partnership

Aspen Bibliography

The Oregon Aspen Project was initiated in response to the decline of aspen groves in Oregon and throughout the Western United States, and the lack of information to guide managers interested in stewardship to enhance this resource. There were three central goals and accompanying objectives for this project which are listed below. The project accomplishments are provided below each bulleted objective

Reduction Of Iron (Iii) And Humic Substances Plays A Major Role In Anaerobic Respiration In An Arctic Peat Soil, David A. Lipson, Mony Jha, Ted K. Raab, Walter C. Oechel

Ted K. Raab

Arctic peat soils contain vast reserves of organic C and are largely anaerobic. However, anaerobic respiration, particularly the role of Fe(III) and humic substances as electron acceptors, is not well understood in such ecosystems. We investigated these processes in a drained thaw lake basin on the Arctic coastal plain near Barrow, Alaska. We measured concentrations of soluble Fe and other potential electron acceptors, described the microbial community, and performed experiments in the laboratory and field to measure net rates of Fe(III) reduction and the relationship of this process to C cycling. In most areas within the basin, aerobic conditions existed …

Low Endemism, Continued Deep-Shallow Interchanges, And Evidence For Cosmopolitan Distributions In Free-Living Marine Nematodes (Order Enoplida), Holly M. Bik, W. Kelley Thomas, David H. Lunt, P. John D. Lambshead

Hubbard Center for Genome Studies (HCGS)

Background: Nematodes represent the most abundant benthic metazoa in one of the largest habitats on earth, the deep sea. Characterizing major patterns of biodiversity within this dominant group is a critical step towards understanding evolutionary patterns across this vast ecosystem. The present study has aimed to place deep-sea nematode species into a phylogenetic framework, investigate relationships between shallow water and deep-sea taxa, and elucidate phylogeographic patterns amongst the deep-sea fauna. Results: Molecular data (18 S and 28 S rRNA) confirms a high diversity amongst deep-sea Enoplids. There is no evidence for endemic deep-sea lineages in Maximum Likelihood or Bayesian phylogenies, …

Molecular Evidence Suggests Multiple Evolutionary Origins Of Sociality In The Polyphenic Spider Anelosimus Studiosus (Araneae: Theridiidae)., Nathaniel O. Weber

Electronic Theses and Dissertations

Anelosimus studiosus exhibits two behavioral phenotypes: subsocial and social. This is the only documented spider inhabiting a temperate climate exhibiting social behavior. While the subsocial phenotype is most common throughout the range, the social behavior occurs in isolated pockets in northern latitudes. This study examines the origins of the social phenotype within a segment of the spider's range. Two hypotheses are tested: 1) pockets of social behavior represent a single origin or 2) pockets of social behavior represent local evolutions, thus leading to multiple origins of evolution. Microsatellite loci were used to determine genetic structure of the population and to …

Lack Of Rhythmicity In The Honey Bee Queen: An Investigation Of Temporal Behavioral Patterns In Apis Mellifera Ligustica., Jennifer N. Johnson

Electronic Theses and Dissertations

Little is known about the behavioral patterns of honey bee queens. To determine if mated honey bee queens possess diel rhythmicity in behavior, we observed them in glass-sided observation hives using three types of observation regimes: focal studies consisting of 2-hour and 24-hour continuous observations as well as scan-sampling of multiple queens. All behaviors (active: walking, inspecting, egg-laying, begging for food, feeding, and grooming self; inactive: standing) occurred at all times of day and night, but no queen showed consistent diel rhythmicity in any of the individual behaviors. There were no consistent diel differences in active versus inactive behaviors or …

Ecoweb 1.1: Ecologists' Cooperative Web Bank, Joel E. Cohen

Cohen Laboratory

ECOWeB is a machine-readable database of several hundred food webs compiled from published sources by several ecologists.