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Lifelines Winter 2010, Southern Adventist University

Lifelines - Biology Department Newsletter

The Winter 2010 issue of Lifelines features articles on research done in the Southern Connections class, the retirement of Dr. David Ekkens, the death of Dr. Richard Seidel, the Allied Health Club's service projects, and a pictorial directory of the 2010 biology and allied health graduates.

Full Issue: Volume 4, Number 1

The Science Journal of the Lander College of Arts and Sciences

No abstract provided.

Post-­Fire Alterations In Mechanical Strength Of Leaves In Heteromeles Arbutifolia, Andrew Hair, Madeline Dilascia, Nick Novella, Taylor Wurdeman

Featured Research

Wildfires in the Santa Monica mountains in Southern California burn down a decent percentage of the local vegetation. However, some plants like Heteromeles Arbutifolia, are considered to be resprouters because they return a mere two years after being burnt down. It is hypothesized that the artificially browsed resprout leaves will have a lower tensile strength than both the young and adult leaves because they use a lower amount of carbohydrates per unit-leaf-area. Data showed that although there was a slight different between the young leaves and the adult leaves of the Heteromeles, there was no statistically significant difference between the …

A Comparison Of The Tensile Strength Of Leaves In Encelia Californica In Canyon And Beach Species, Anna Chowaniec, Annie Lee, Hayley Springs

Featured Research

Our research is concerned with the further exploration of leaf biomechanics, a relatively unexamined field. The purpose of this experiment was to find a correlation between environmental stress factors and tensile strength of leaves of Encelia californica. We hypothesized the beach species would have a higher tensile strength than canyon species. After evaluating data collected from both Pepperdine’s Presidents Canyon and Malibu beach we found that while the canyon species could withstand a higher maximum load of force, there was no difference between the canyon and the beach species with leaf area taken into account. Using Young’s Modulus, we …

Mathematical Biology At An Undergraduate Liberal Arts College, Stephen C. Adolph, Lisette G. De Pillis

All HMC Faculty Publications and Research

Since 2002 we have offered an undergraduate major in Mathematical Biology at Harvey Mudd College. The major was developed and is administered jointly by the mathematics and biology faculty. In this paper we describe the major, courses, and faculty and student research and discuss some of the challenges and opportunities we have experienced.

Full Issue: Volume 3, Number 1

The Science Journal of the Lander College of Arts and Sciences

No abstract provided.

Effect Of Fertilizer On Leaf Tensile Strength In Salvia Leucophylla, Tawny Lindahl, John Buie, Eiichiro Uemura

Featured Research

This experiment sought to establish a connection between short term growth in Salvia leucophylla found in Southern California and nutrient availability in the soil. It was hypothesized that adding artificially produced nutrient mix Miracle Grow would increase the strength of the leaves in the herb after one week of addition. Newer leaves were tested in the Instron device for tensile strength after one week, and after data analysis, it was concluded that there was no difference in tensile strength of leaves treated with fertilizer compared with leaves without fertilizer.

Differences In Hydraulic Conductance (Kh) As A Function Of Leaf Area (Ks Leaf) And Xylem Size (Ks Xylem) In Encelia Californica And Venegasia Carpesioides, Tony Audin, Andrew Dudley, Janel Gonzalez

Featured Research

Southern California and the Santa Monica Mountains experience a climate similar to that of the Mediterranean basin. This means hot, dry summers, mild, wet winters, and large amounts of plant diversity. A major issue that can affect these regions is water availability and processing. To demonstrate this, hydraulic conductance (Kh) was measured as a function of leaf area (KS Leaf) and xylem size (KS Xylem). Two vascular plants were used for this study, Encelia californica and Venegasia carpesioides. This is because they are similar morphologically but are different genus and species. It was hypothesized that the larger plant (V. carpesioides) …

The Affect Of Temperature On The Fluorescence Of Heteromeles Arbutifolia (Hollywood) In The Santa Monica Mountains, Patrick Y. Chisum, Adam S. Graham, Arthur C. Sanders

Featured Research

Presented here is a comparison of the predawn fluorescence of adult Heteromeles arbutifolia growing on the Pepperdine Seaver campus next to the lacrosse field, and adult Heteromeles growing in Tapia canyon. The analysis of the leaf temperature measured by an IR thermometer showed an average of 9.32°C drop when measuring plants in Tapia canyon compared to those growing on the warmer Pepperdine campus. The air temperature measured by the Kestrel and IR thermometer showed Tapia canyon being an average of 7.27°C colder than predawn measurements on Pepperdine campus. Finally, the fluorescence of the plants in both locations was measured using …

Effect Of Petiole-­To-­Branchlet Angle On Tensile Stress And Tensile Strength In Heteromeles Arbutifolia, Matt W. Andrus, Anthony P. Lisankis, Valen C. Anderson

Featured Research

Heteromeles arbutifolia an important chaparral species of southern California, Is a food source for mule deer (Odocoileus hemionus). This predation has become more pronounced as the climate shifts to hotter, drier, and longer summers. Other species that the deer normally feed on cannot survive these harsh conditions, while Heteromeles arbutifolia is able to persevere (Letourneau, 2004). We decided that there must be mechanisms involved in the petiole of leafs to keep them from being pulled off by deer and strong winds. Our group hypothesized that as the angle between the petiole and branchlet increased, the tensile strength of the petiole …

Comparing Leaf Properties Of Inland And Coastal Malosma Laurina In The Santa Monica Mountains, Rosemary Busch Conn, Lauren Parker, Brittany Sawrey

Featured Research

Our group chose Malosma laurina, commonly known as Laurel Sumac, to observe and test. We hypothesized that there would be difference in photosynthetic trade-offs and capabilities between coastal and inland populations, specifically with respect to leaves. This was based on the low freezing tolerance in Malosma laurina (Pratt et al. 2005), and hypothesized that based on this stress, resources would be allocated differently in inland leaves than in coastal leaves. This hypothesis was tested using the indices of Normalized Difference Vegetation Index (NDVI), the Photochemical Reflectance Index (PRI), the ratio of green to red reflectance, and Leaf Specific Area …

Tensile Strength Of Malosma Laurina Leaves In Wet And Dry Conditions, T. Candelore, N. Despenza, L. Garrison, L. Hinther

Featured Research

Pepperdine University is one located in one of the most diverse places of the world. It is located in the Mediterranean which occupies less than 5% of the earth's landmass and is only found in five areas which includes California. On the campus there are several canyons. One of the canyons is called Winter Canyon. The canyon contained a plant called Malosma laurina which is located in a riparian environment and a chaparral environment. The plant grows in both areas however, our hypothesis was that the dry plants' leaves would demonstrate more plasticity. The soil humidity was also measured to …

Root Tensile Strength In A Native And Non-­Native Species Of The Coastal Chaparral Community, Jamie Elmquist, Andrea Lim, Amanda Scholl, Amanda Vest

Featured Research

Non-­native species are regularly introduced into environments in which they replace existing native species and drastically influence the ecological characteristics of the area and the habitat of the living organisms surrounding them. In the botanical field of study, invasive plant species can choke out native species thus making them endangered or extinct. Specifically in the Santa Monica Mountains of Southern California, there are over 300 non-­native species of plants, each the source of its own repercussions and having both positive and negative effects on the environment. One specific non-­native species, Carpobrotus edulis (ice plant) replaces the native Coreopsis gigante (giant …

Effects Of Uv Light On Local Stream Frog Behavior, John Buie, Eiichiro Uemura, Candy Hwang, D. Lee, Craig Sutter, Evan Mattiasen, Thomas Vandergon, Rodney Honeycutt, Lee Kats

Featured Research

Amphibian declines have been well documented throughout the world. Several studies have examined whether UV radiation from the sun is a possible contributing cause to declining populations. In Southern California, two closely related species of treefrogs, Pseudacris hypochondriaca and Pseudacris cadaverina, coexist in many perennial streams. P. hypochondriaca is primarily nocturnal while P. cadaverina is known to bask in direct sunlight. The purpose of the study is to determine how the two different species of frogs will react under different types of light emitted by a portable flashlight. The light was emitting either UV radiation or visible light, or …

Building Better Scientists Through Cross-Disciplinary Collaboration In Synthetic Biology: A Report From The Genome Consortium For Active Teaching Workshop 2010, Michael J. Wolyniak, Consuelo J. Alvarez, Vidya Chandrasekaran, Theresa M. Grana, Andrea Holgado, Christopher J. Jones, Robert W. Morris, Anil L. Pereira, Joyce Stamm, Talitha M. Washington, Yixin Yang

Biological Sciences Research

A common problem faced by primarily undergraduate institutions is the lack of funding and material support needed to adequately expose students to modern biology, including synthetic biology. To help alleviate this problem, the Genome Consortium for Active Teaching (GCAT) was founded in 2000 by Malcolm Campbell at Davidson College to bring genomics into the undergraduate curriculum. GCAT’s first tangible activity was to serve as a central clearinghouse both for the purchase and reading of DNA microarrays and for information on how to execute genomics experiments at undergraduate institutions. In response to the evolution of molecular biology in the last decade, …

Introduction: Protistan Biology, Horizontal Gene Transfer, And Common Descent Uncover Faulty Logic In Intelligent Design, Avelina Espinosa

Arts & Sciences Faculty Publications

THE International Society of Protistologists (ISOP) organized a pre-meeting workshop entitled ‘‘Horizontal Gene Transfer and Phylogenetic Evolution Debunk Intelligent Design,’’ as part of the 1st North American Section meeting held June 11–13, 2009, at Roger Williams University, Bristol, RI, USA. This workshop focused on the acceptance of Darwinian evolution in the United States and the role of intelligent design (ID) in the ongoing controversy between scientific knowledge and popular belief. Intelligent design, a doctrine born in the 1980s, proposes that a ‘‘Designer’’ is responsible for the complexity in biological systems and that Darwinism cannot explain holistically the origin and evolution …

Bacterial Acquisition In Juveniles Of Several Broadcast Spawning Coral Species, Koty H. Sharp, Kim B. Ritchie

Arts & Sciences Faculty Publications

Coral animals harbor diverse microorganisms in their tissues, including archaea, bacteria, viruses, and zooxanthellae. The extent to which coral-bacterial associations are specific and the mechanisms for their maintenance across generations in the environment are unknown. The high diversity of bacteria in adult coral colonies has made it challenging to identify species-specific patterns. Localization of bacteria in gametes and larvae of corals presents an opportunity for determining when bacterial-coral associations are initiated and whether they are dynamic throughout early development. This study focuses on the early onset of bacterial associations in the mass spawning corals Montastraea annularis, M. franksi, M. faveolata, …

Review Of The Species Of Gugolzia Delucchi And Steffan (Hymenoptera: Pteromalidae) In Europe And Turkey, With Descriptions Of New Species, Mi̇kdat Doğanlar, Oğuzhan Doğanlar

Turkish Journal of Zoology

The species of Gugolzia (Hymenoptera: Chalcidoidea, Pteromalidae) in Europe and Turkey were reviewed, and an identification key for differentiating the species is provided. Newly discovered diagnostic characters of the genus were added to the diagnoses given by earlier authors. Species were recorded as parasitoids of phytophagous Eurytomidae (Hymenoptera: Chalcidoidea). New host and distributions are for Gugolzia harmolitae, which was reared from Tetramesa romana feeding on shoots of Arundo donax (Poaceae), Gugolzia karadagae n.sp. from Eurytoma plotnikovi feeding on fruits of Pistacia vera together with Megastigmus pistaciae (Chalcidoidea: Torymidae) in Gaziantep province, and Gugolzia melengicia n.sp. from fruits of Pistacia terebinthi …

Apparent Competition With An Invasive Plant Hastens The Extinction Of An Endangered Lupine, Emily M. Dangremond, Eleanor A. Pardini, Tiffany M. Knight

Biology Faculty Research

Invasive plants may compete with native plants by increasing the pressure of native consumers, a mechanism known as "apparent competition." Apparent competition can be as strong as or stronger than direct competition, but the role of apparent competition has rarely been examined in biological invasions. We used four years of demographic data and seed-removal experiments to determine if introduced grasses caused elevated levels of seed consumption on native plant species in a coastal dune system in California, USA. We show that the endangered, coastal dune plant Lupinus tidestromii experiences high levels of pre-dispersal seed consumption by the native rodent Peromyscus …

Seed Dispersal By Pulp Consumers, Not ‘‘Legitimate’’ Seed Dispersers, Increases Guettarda Viburnoides Population Growth, Andrea P. Loayza, Tiffany M. Knight

Biology Faculty Research

We examined the effect of seed dispersal by Purplish Jays (Cyanocorax cyanomelas; pulp consumers) and the Chestnut-eared Araçari (Pteroglossus castanotis; "legitimate" seed dispersers) on population growth of the small tree Guettarda viburnoides (Rubiaceae) in northeastern Bolivian savannas. Because each bird species differs with respect to feeding and post-feeding behavior, we hypothesized that seed dispersal by each species will contribute differently to the rate of increase of G. viburnoides, but that seed dispersal by either species will increase population growth when compared to a scenario with no seed dispersal. To examine the effects of individual dispersers on the future population size …

Bryostatins: Biological Context And Biotechnological Prospects, Amaro E. Trindade-Silva, Grace E. Lim-Fong, Koty H. Sharp

Arts & Sciences Faculty Publications

Coral animals harbor diverse microorganisms in their tissues, including archaea, bacteria, viruses, and Bryostatins are a family of protein kinase C modulators that have potential applications in biomedicine. Found in miniscule quantities in a small marine invertebrate, lack of supply has hampered their development. In recent years, bryostatins have been shown to have potent bioactivity in the central nervous system, an uncultivated marine bacterial symbiont has been shown to be the likely natural source of the bryostatins, the bryostatin biosynthetic genes have been identified and characterized, and bryostatin analogues with promising biological activity have been developed and tested. Challenges in …

A Three-Dimensional Computer Simulation Model Reveals The Mechanisms For Self-Organization Of Plant Cortical Microtubules Into Oblique Arrays, Ezgi Can Eren, Ram Dixit, Natarajan Gautam

Biology Faculty Research

The noncentrosomal cortical microtubules (CMTs) of plant cells self-organize into a parallel three-dimensional (3D) array that is oriented transverse to the cell elongation axis in wild-type plants and is oblique in some of the mutants that show twisted growth. To study the mechanisms of CMT array organization, we developed a 3D computer simulation model based on experimentally observed properties of CMTs. Our computer model accurately mimics transverse array organization and other fundamental properties of CMTs observed in rapidly elongating wild-type cells as well as the defective CMT phenotypes observed in the Arabidopsis mor1-1 and fra2 mutants. We found that CMT …

Seeing The Future: Biology Research Allows Undergraduates New Insight Into Their Own Futures, Merideth Krevosky, Jeffery Bowen

Bridgewater Review

No abstract provided.

Population Ecology And Reproductive Biology Of The Diamondback Watersnake, Nerodia Rhombifer (Serpentes: Colubridae), In Southernmost Texas, Ruben D. Zamora

Theses and Dissertations - UTB/UTPA

Nerodia rhombifer is a polytypic, semi-aquatic snake with a broad geographical distribution ranging from the American Midwest southward to Chiapas, Mexico. Although relatively abundant throughout much of its range, few ecological studies of the species have been conducted. This study provides basic population ecology information in a subtropical habitat. Population data were obtained in a mark-recapture study at Santa Ana National Wildlife Refuge, Hidalgo County, Texas, from August 1995 to December 1998. Specimens taken elsewhere in Hidalgo County provided information on the reproductive biology. This study provides the first absolute density estimates from anywhere within the species’ range. Quantitative information …

An Intertidal Sea Star Adjusts Thermal Inertia To Avoid Extreme Body Temperatures, Sylvain Pincebourde, Eric Sanford, Brian Helmuth

Faculty Publications

The body temperature of ectotherms is influenced by the interaction of abiotic conditions, morphology, and behavior. Although organisms living in different thermal habitats may exhibit morphological plasticity or move from unfavorable locations, there are few examples of animals adjusting their thermal properties in response to short-term changes in local conditions. Here, we show that the intertidal sea star Pisaster ochraceus modulates its thermal inertia in response to prior thermal exposure. After exposure to high body temperature at low tide, sea stars increase the amount of colder than-air fluid in their coelomic cavity when submerged during high tide, resulting in a …

Lifelines Fall 2009, Southern Adventist University

Lifelines - Biology Department Newsletter

The Fall 2009 issue of Lifelines includes articles on Southern's Ancient DNA Project, an alumni feature, student research, and news from the Pre-Dent Club.

An Examination Of The Correlation Between Shoot Apical Meristem Size And Leaf Heterophylly In Pisum Sativum, Cynthia Mary Halfman

Undergraduate Honors Thesis Collection

This study is a quantitative examination of the ramifications of leaf development as influenced by the size of the shoot apical meristem. I wish not to delve into a genetic examination of the shoot apical meristem but rather into the possible correlation between the apical meristem size and leaf heterophylly. If changes in shoot apical meristem size influence heterophylly in leaves, then as shoot apical meristem changes, leaf characteristics will change. This change may result from two different relationships.

Protozoan Vaccine Candidate Homologues In Tetrahymena Thermophila, Justin Schumacher

Senior Honors Projects

Tetrahymena thermophila is a member of the phylum Ciliophora (the ciliated protozoa) and is currently of great interest due to its unique qualities that make it useful as a model for research directed towards understanding how eukaryotic cells function. Recently, the T. thermophila genome was sequenced, and made available online. Since Tetrahymena is a member of the Alveolata, the major eukaryotic clade that also contains the apicomplexan parasites that cause a number of serious human and animal diseases, we sought to determine whether the genes coding for apicomplexan vaccine candidates were represented in the genome of Tetrahymena. In addition, we …

Role Of The P21 Protein In The Fanconi Anemia Pathway, Mae Shen

Senior Honors Projects

Our bodies are constantly exposed to a variety of substances that damage our DNA, such as ultraviolet radiation, environmental chemicals, and the reactive by-products of our metabolism. To prevent the harmful effects that may result from such damage, our cells possess multiple DNA repair mechanisms. However, if their ability to repair damaged DNA is somehow impaired, cells are more likely to accumulate potentially harmful mutations, including those that may lead to the development of cancer.

In Fanconi anemia (FA), a rare recessive genetic disorder, a defect in a DNA repair pathway results in increased sensitivity to a particular type of …

The Effects Of Tail Flukes On The Swimming Pattern Of Atlantic Bottlenose Dolphins, Lauri Leach

Senior Honors Projects

Atlantic bottlenose dolphins are top predators in the wild, due in part because they are excellent swimmers. When dolphins swim through the water, the tail flukes are moved in an up and down motion to propel the animal through the water. They use the pectoral fins for steering and braking, and the dorsal fin for stabilization as they swim. Using this style of swimming, Atlantic bottlenose dolphins can swim up to 25 miles per hour and leap 15 to 20 feet into the air.

During the spring of 2008, I was an intern at the Clearwater Marine Aquarium in Florida. …