Graduate Research Symposium 2009
Saturday, March 21st 2009
The EEB Graduate Student Symposium is an all day event where graduate students present their research to other graduate students and faculty. Any EEB graduate student can present: BSMS, masters, PhD, old and new students. New graduate students usually present research ideas or preliminary data, while those more ‘seasoned’ students present their most recent results, often in preparation for upcoming spring and summer meetings.
|8:30-9:00||Coffee & Tea (drinks only)|
|9:00-9:15||Dean Teitelbaum||Welcome Address|
|9:15-9:30||Laura Cisneros|| Comparison of tropical metacommunities along an extensive
|9:30-9:45||Vanessa Boukili||Plant functional traits and patterns of community assembly during natural rain forest regeneration|
|9:45-10:00||Frank Smith|| The Genetic Loci of Evolutionary Change of Tribolium Beetle Antennal
|10:00-10:15||Kerri Mocko||In the South African veld: solar tracking and temperatures in contrasting leaf shapes of Pelargonium|
|10:15-10:30||Yu(Daniel) Fan||A conditional autoregressive (CAR) model for detecting site dependence in evolution of DNA sequences|
|10:30-11:00||Morning Break - Drinks and Fruit|
|11:00-11:15||Karolina Fucikova||What Bracteacoccus is not|
|11:15-11:30||Lori Benoit||Phylogenetic relationships and genetic diversity of the invasive aquatic angiosperm Hydrilla verticillata (l.f.) Royle (Hydrocharitaceae)|
|11:30-11:45||Adam Wilson||Fire, climate & biomass (from space)|
|11:45-12:00||Nicholas Tippery||But will it float? Evolution of inflorescence architecture in Nymphoides (Menyanthaceae)|
|12:00-1:30||Lunch - Sandwiches and Salad|
|1:30-2:00||Roland de Gouvenain||Keynote Address: Population ecology and life history traits of Cupressus forbesii: human influences from changes in fire regime|
|2:00-2:15||Tobias Landberg|| Experimental manipulation of maternal investment in sister salamander
|2:15-2:30||Alejandro Rico Guevara||Evolutionary Insights About Nectarivores’ Bills Structures|
|2:30-2:45||Rachel Prunier||Pelargonium Community Structuring|
|2:45-2:50||Nicholas Tippery||Top graduate student webpages of 2009|
Comparison of tropical metacommunities along an extensive elevational gradient
Insert Abstract Here...
Plant functional traits and patterns of community assembly during natural rain forest regeneration
The global reduction in tropical old-growth forests urges a more complete understanding of how these forests can regenerate following disturbance. Plant functional traits are morphological and physiological characteristics of species which will likely illuminate successional pathways due to their importance in plant performance. Community level measures of functional trait values are valuable in assessing mechanisms of community assembly during secondary forest regeneration. Preliminary results of functional traits from dominant species in one secondary and one mature forest at La Selva Biological Station in Costa Rica show predicted trends of community assembly in functional traits. Further research will clarify patterns and elucidate conservation and management strategies.
The Genetic Loci of Evolutionary Change of Tribolium Beetle Antennal Morphology
Insert Abstract Here...
In the South African veld: solar tracking and temperatures in contrasting leaf shapes of Pelargonium
Insert Abstract Here...
A conditional autoregressive (CAR) model for detecting site dependence in evolution of DNA sequences
ABSTRACT: Most methods for phylogenetic analysis assume that every site in a DNA sequence evolves independently. However, this assumption is violated in many cases, especially for DNA sequences coding for proteins and those with secondary or tertiary structure after transcription. Although the auto-discrete-gamma model and hidden Markov-chain model implemented separately by Yang (1995a) and Felsenstein and Churchill (1996) allow rates to be correlated across adjacent sites, they cannot model more complex correlation scenarios. Here, we describe an approach to modeling the dependence of evolutionary rates among DNA sequence sites using a conditional autoregressive (CAR) model. CAR models allow a priori knowledge of a molecule's secondary or tertiary structure to be used for explaining the correlated evolution in them, and are capable of being extended to many situations involving spatial correlations. We implemented the model in a fully Bayesian approach, with all parameters of the model considered as random variables. The marginal likelihood is calculated by Steppingstone sampling for comparing the CAR model with alternative models.
What Bracteacoccus is not.
Traditionally, the classification of coccoid green algae depended on subtle morphological differences, without much information about the potential variation or plasticity of these traits. The use of molecular sequence data provides a high number of characters that are not subject to phenotypic plasticity and therefore are assumed to provide a more direct measure of phylogenetic relationships. Molecular phylogenetic studies of coccoids often yield unexpected results, uncovering cryptic diversity as well as placing taxa in dramatically different positions from those expected under the morphological paradigm. As part of a monographic study of the chlorophycean genus Bracteacoccus, several strains deposited in culture collections under this generic name were found to belong to other green algal genera. Although morphologically similar to young cells of Bracteacoccus, these algae were demonstrated to belong to the genera Myrmecia and Pseudomuriella based on 18S and rbcL sequence data. These cases may represent two of potentially many discrepancies of morphological and sequence data.
Phylogenetic relationships and genetic diversity of the invasive aquatic angiosperm Hydrilla verticillata (l.f.) Royle (Hydrocharitaceae)
Insert Abstract Here...
Fire, climate, & biomass (from space)
The U.S. Climate Change Science Program has recognized the need to understand the ecological impacts of global climate change on phenology and disturbance regimes (such as fire). In the Cape Floristic Region of South Africa, analysis of the historical (1980-2006) fire record reveals that increased temperatures and decreased precipitation increases fire probability and that the mean fire return time has shortened by four years since 1950. But before we can make projections about future fire regimes under a different climate, we must understand how biomass (fuel load) accumulation is also affected by climate change. We show that remotely sensed data can be used to monitor post-fire biomass accumulation in this system, which opens possibilities to use the satellite data archive to investigate how biomass accumulation rates are affected by weather.
But will it float? Evolution of inflorescence architecture in Nymphoides (Menyanthaceae)
The genus Nymphoides includes about 40-50 species distributed worldwide, the majority of which have floating leaves supporting flowers that must be pollinated above water. The evolutionary origin of the floating-leaved habit in this group is particularly interesting because of its association with the specialized inflorescence architecture. Several broad inflorescence types exist in Nymphoides, with the most specialized consisting of a single cluster of flowers supported by a single floating leaf. The nearest relatives of Nymphoides do not have floating leaves obligately associated with their inflorescences, and these represent a valuable point of comparison when reconstructing the evolution of inflorescence architecture in Nymphoides. Published morphological accounts of inflorescences in Nymphoides describe them as consisting of successive sympodial units, in which the apex terminates and growth continues from an axillary bud. I have developed a hypothesis about how the different inflorescence types evolved through successive reduction in the number of leaves and flowers per sympodial unit. Ultimately, the most derived morphology (the clustered-flower type) represents several sympodial units, each consisting of a single bract and a single flower.
Roland de Gouvenain
Population ecology and life history traits of Cupressus forbesii: human influences from changes in fire regime
We use the Tecate cypress (Cupressus forebesii Jeps.), a fire-adapted short-lived tree species endemic to southern California and northern Baja, Mexico, as a model to examine whether more than a century of fire regime difference across the US-Mexico international border has selected for different reproductive life history traits, produced different population demographics, and generated different genetic variability among perennial plant populations. Our hypotheses are that Baja populations, being subjected to a more variable and fine grained fire regime, should exhibit multiple age classes, older tree age at maturity, facultative serotiny, and greater among-population genetic variability. California populations on the other hand, being subjected to a very narrow variation in mostly stand-replacement fire regime resulting from strict fire suppression management, should exhibit fewer age classes, younger tree age at maturity, obligate serotiny, and lower among-population genetic variability. Preliminary data indicate that Baja populations may exhibit multiple age classes including adults and young seedlings, even though no stand-replacement fire has occurred there in at least 35 years, a phenomenon not observed on the US side of the border.
Experimental manipulation of maternal investment in sister salamander species
Insert Abstract Here...
Alejandro Rico Guevara
Evolutionary Insights About Nectarivores’ Bills Structures
Studying specialized nectarivorous birds, I have found a set of morphological traits that seems to be involved in their feeding performance and social organization. Features improving feeding efficiency include structures finely tuned by physical laws in the nectar extraction process. Traits related to social systems are proposed sexually dimorphic weapons employed in fights for resources.
Pelargonium community structure in South Africa: The influence of phylogeny, body plan and climate.
I investigated the roles that phylogeny, body plan and climate play in the structuring of small scale Pelargonium communities. I found that there is no evidence that genetic relatedness predicts how close individuals live to each other.