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Biology Faculty Works

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Articles 151 - 180 of 397

Full-Text Articles in Biology

Novelty Induces Behavioural And Glucocorticoid Responses In A Songbird Artificially Selected For Divergent Personalities, Alexander T. Baugh, Kailyn Faye R. Witonsky , '16, S. C. Davidson, Laura P. Hyder , '16, M. Hau, K. Van Oers Aug 2017

Novelty Induces Behavioural And Glucocorticoid Responses In A Songbird Artificially Selected For Divergent Personalities, Alexander T. Baugh, Kailyn Faye R. Witonsky , '16, S. C. Davidson, Laura P. Hyder , '16, M. Hau, K. Van Oers

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Stress physiology is thought to contribute to individual differences in behaviour. In part this reflects the fact that canonical personality measures consist of responses to challenges, including novel objects and environments. Exposure to novelty is typically assumed to induce a moderate increase in glucocorticoids (CORT), although this has rarely been tested. We tested this assumption using great tits, Parus major, selected for divergent personalities (bold-fast and shy-slow explorers), predicting that the shy birds would exhibit higher CORT following exposure to a novel object. We also scored behavioural responses to the novel object, predicting that bold birds would more frequently approach …


Risk-Averse Personalities Have A Systemically Potentiated Neuroendocrine Stress Axis: A Multilevel Experiment In Parus Major, Alexander T. Baugh, Rebecca A. Senft , '15, Marian L. Firke , '14, Abigail P. Lauder , '15, J. Schroeder, S. L. Meddle, Kees Van Oers, M. Hau Jul 2017

Risk-Averse Personalities Have A Systemically Potentiated Neuroendocrine Stress Axis: A Multilevel Experiment In Parus Major, Alexander T. Baugh, Rebecca A. Senft , '15, Marian L. Firke , '14, Abigail P. Lauder , '15, J. Schroeder, S. L. Meddle, Kees Van Oers, M. Hau

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Hormonal pleiotropy—the simultaneous influence of a single hormone on multiple traits—has been hypothesized as an important mechanism underlying personality, and circulating glucocorticoids are central to this idea. A major gap in our understanding is the neural basis for this link. Here we examine the stability and structure of behavioral, endocrine and neuroendocrine traits in a population of songbirds (Parus major). Upon identifying stable and covarying behavioral and endocrine traits, we test the hypothesis that risk-averse personalities exhibit a neuroendocrine stress axis that is systemically potentiated—characterized by stronger glucocorticoid reactivity and weaker negative feedback. We show high among-individual variation and covariation …


Higher Predation Risk For Insect Prey At Low Latitudes And Elevations, T. Roslin, B. Hardwick, V. Novotny, W. K. Petry, N. R. Andrew, A. Asmus, I. C. Barrio, Y. Basset, A. L. Boesing, T. C. Bonebrake, E. K. Cameron, W. Dáttilo, D. A. Donoso, P. Drozd, C. L. Gray, D. S. Hik, S. J. Hill, T. Hopkins, S. Huang, B. Koane, B. Laird-Hopkins, L. Laukkanen, O. T. Lewis, S. Milne, I. Mwesige, A. Nakamura, C. S. Nell, Elizabeth Nichols, A. Prokurat, K. Sam, N. M. Schmidt, A. Slade, V. Slade, A. Suchanková, T. Teder, S. Van Nouhuys, V. Vandvik, A. Weissflog, V. Zhukovich, E. M. Slade May 2017

Higher Predation Risk For Insect Prey At Low Latitudes And Elevations, T. Roslin, B. Hardwick, V. Novotny, W. K. Petry, N. R. Andrew, A. Asmus, I. C. Barrio, Y. Basset, A. L. Boesing, T. C. Bonebrake, E. K. Cameron, W. Dáttilo, D. A. Donoso, P. Drozd, C. L. Gray, D. S. Hik, S. J. Hill, T. Hopkins, S. Huang, B. Koane, B. Laird-Hopkins, L. Laukkanen, O. T. Lewis, S. Milne, I. Mwesige, A. Nakamura, C. S. Nell, Elizabeth Nichols, A. Prokurat, K. Sam, N. M. Schmidt, A. Slade, V. Slade, A. Suchanková, T. Teder, S. Van Nouhuys, V. Vandvik, A. Weissflog, V. Zhukovich, E. M. Slade

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Biotic interactions underlie ecosystem structure and function, but predicting interaction outcomes is difficult. We tested the hypothesis that biotic interaction strength increases toward the equator, using a global experiment with model caterpillars to measure predation risk. Across an 11,660-kilometer latitudinal gradient spanning six continents, we found increasing predation toward the equator, with a parallel pattern of increasing predation toward lower elevations. Patterns across both latitude and elevation were driven by arthropod predators, with no systematic trend in attack rates by birds or mammals. These matching gradients at global and regional scales suggest consistent drivers of biotic interaction strength, a finding …


Demethylated Hsatii Dna And Hsatii Rna Foci Sequester Prc1 And Mecp2 Into Cancer-Specific Nuclear Bodies, L. L. Hall, M. Byron, Dawn M. Carone, T. W. Whitfield, G. P. Pouliot, A. Fischer, P. Jones, J. B. Lawrence Mar 2017

Demethylated Hsatii Dna And Hsatii Rna Foci Sequester Prc1 And Mecp2 Into Cancer-Specific Nuclear Bodies, L. L. Hall, M. Byron, Dawn M. Carone, T. W. Whitfield, G. P. Pouliot, A. Fischer, P. Jones, J. B. Lawrence

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This study reveals that high-copy satellite II (HSATII) sequences in the human genome can bind and impact distribution of chromatin regulatory proteins and that this goes awry in cancer. In many cancers, master regulatory proteins form two types of cancer-specific nuclear bodies, caused by locus-specific deregulation of HSATII. DNA demethylation at the 1q12 mega-satellite, common in cancer, causes PRC1 aggregation into prominent Cancer-Associated Polycomb (CAP) bodies. These loci remain silent, whereas HSATII loci with reduced PRC1 become derepressed, reflecting imbalanced distribution of UbH2A on these and other PcG-regulated loci. Large nuclear foci of HSATII RNA form and sequester copious MeCP2 …


Wfs1 Is Expressed In Dopaminoceptive Regions Of The Amniote Brain And Modulates Levels Of D1-Like Receptors, T. Tekko, T. Lakspere, A. Allikalt, J. End, K. R. Kõlvart, T. Jagomäe, A. Terasmaa, M.-A. Philips, T. Visnapuu, F. Väärtnõu, Scott F. Gilbert, A. Rinken, E. Vasar, K. Lilleväli Mar 2017

Wfs1 Is Expressed In Dopaminoceptive Regions Of The Amniote Brain And Modulates Levels Of D1-Like Receptors, T. Tekko, T. Lakspere, A. Allikalt, J. End, K. R. Kõlvart, T. Jagomäe, A. Terasmaa, M.-A. Philips, T. Visnapuu, F. Väärtnõu, Scott F. Gilbert, A. Rinken, E. Vasar, K. Lilleväli

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During amniote evolution, the construction of the forebrain has diverged across different lineages, and accompanying the structural changes, functional diversification of the homologous brain regions has occurred. This can be assessed by studying the expression patterns of marker genes that are relevant in particular functional circuits. In all vertebrates, the dopaminergic system is responsible for the behavioral responses to environmental stimuli. Here we show that the brain regions that receive dopaminergic input through dopamine receptor D1 are relatively conserved, but with some important variations between three evolutionarily distant vertebrate lines–house mouse (Mus musculus), domestic chick (Gallus gallus domesticus) / common …


Neuroembryology, D. Darnell, Scott F. Gilbert Jan 2017

Neuroembryology, D. Darnell, Scott F. Gilbert

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How is it that some cells become neurons? And how is it that neurons become organized in the spinal cord and brain to allow us to walk and talk, to see, recall events in our lives, feel pain, keep our balance, and think? The cells that are specified to form the brain and spinal cord are originally located on the outside surface of the embryo. They loop inward to form the neural tube in a process called neurulation. Structures that are nearby send signals to the posterior neural tube to form and pattern the spinal cord so that the dorsal …


Mechanical Properties Of Sediment Determine Burrowing Success And Influence Distribution Of Two Lugworm Species, R. L. Crane, Rachel Merz Jan 2017

Mechanical Properties Of Sediment Determine Burrowing Success And Influence Distribution Of Two Lugworm Species, R. L. Crane, Rachel Merz

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We apply new perspectives on how organisms burrow by examining the association of in situ variation in sediment mechanical properties with burrowing ability and species distribution of two sympatric lugworms, Abarenicola pacifica and Abarenicola claparedi. We quantified the sediment's resistance to penetration and its grain size distribution at sites inhabited by each species. Abarenicola pacifica individuals were found in significantly harder to penetrate, more heterogeneous sediments. We compared worm burrowing ability using reciprocal transplant experiments. Worms from firmer sediments, A. pacifica, were able to make successful steep burrows in sediments characteristic of either species. In contrast, A. claparedi individuals often …


Effect Of Fuel Deposition Rate On Departure Fuel Load Of Migratory Songbirds During Spring Stopover Along The Northern Coast Of The Gulf Of Mexico, Kristen M. Covino Jan 2017

Effect Of Fuel Deposition Rate On Departure Fuel Load Of Migratory Songbirds During Spring Stopover Along The Northern Coast Of The Gulf Of Mexico, Kristen M. Covino

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Migrants are generally assumed to minimize their overall migration time by adjusting their departure fuel loads (DFL) in relation to anticipated and experienced fuel deposition rates (FDRs). We utilized a 21-yr long migration banding station dataset to examine the relationship between FDR and DFL during spring migration in six Nearctic-Neotropical migratory songbird species during stopover along the northern coast of the Gulf of Mexico (GOM) following trans-gulf flight. Estimates of fuel stores, stopover durations, and FDRs from our long term migration data set were combined to determine DFL. We expected and found that migrants across all six species adjust their …


Osm1 Facilitates The Transfer Of Electrons From Erv1 To Fumarate In The Redox-Regulated Import Pathway In The Mitochondrial Intermembrane Space, Deepa V. Dabir Jan 2017

Osm1 Facilitates The Transfer Of Electrons From Erv1 To Fumarate In The Redox-Regulated Import Pathway In The Mitochondrial Intermembrane Space, Deepa V. Dabir

Biology Faculty Works

Prokaryotes have aerobic and anaerobic electron acceptors for oxidative folding of periplasmic proteins. The mitochondrial intermembrane space has an analogous pathway with the oxidoreductase Mia40 and sulfhydryl oxidase Erv1, termed the mitochondrial intermembrane space assembly (MIA) pathway. The aerobic electron acceptors include oxygen and cytochrome c, but an acceptor that can function under anaerobic conditions has not been identified. Here we show that the fumarate reductase Osm1, which facilitates electron transfer from fumarate to succinate, fills this gap as a new electron acceptor. In addition to microsomes, Osm1 localizes to the mitochondrial intermembrane space and assembles with Erv1 in a …


Clinical Implications Of Augmenter Of Liver Regeneration In Cancer: A Systematic Review, Deepa V. Dabir Jan 2017

Clinical Implications Of Augmenter Of Liver Regeneration In Cancer: A Systematic Review, Deepa V. Dabir

Biology Faculty Works

Background/Aim: Hepatocellular carcinoma is a substantial healthcare burden with high prevalence and poor prognosiS. As such, efforts are continually made to uncover molecules relevant in cancer biology, that are exploitable as targets for therapy. The mitochondrion is the powerhouse of the cell and exhibits altered functionality in the malignant state, including aberrant regulation of apoptosis and cellular respiration. Augmenter of liver regeneration (ALR) is a multifunctional mitochondrial protein that demonstrates antioxidative and anti-apoptotic properties and plays a key role in liver regeneration. Materials and Methods: The present study systematically reviews the available literature on the role of ALR in cancer. …


Simultaneous Synergist, Antagonistic, And Additive Interactions Between Multiple Local Stressors All Degrade Algal Turf Communities On Coral Reefs, Sarah Joy Bittick Jan 2017

Simultaneous Synergist, Antagonistic, And Additive Interactions Between Multiple Local Stressors All Degrade Algal Turf Communities On Coral Reefs, Sarah Joy Bittick

Biology Faculty Works

1. Ecological communities are subjected to multiple anthropogenic stressors at both global and local scales that are increasing in number and magnitude. Stressors can interact in complex ways and are classified as additive, synergistic or antagonistic; the nature of the interaction is key to predicting changes and understanding community resilience. Coral reefs are among the most impacted communities and have shifted from coral to algal-dominated states, and overfishing, nutrient enrichment and sedimentation are local stressors that often cooccur and may support degraded algal states. Short algal turfs are abundant benthic space holders on healthy reefs that may be pushed by …


Biological Individuality: A Relational Reading, Scott F. Gilbert Jan 2017

Biological Individuality: A Relational Reading, Scott F. Gilbert

Biology Faculty Works

No abstract provided.


Grnsight: A Web Application And Service For Visualizing Models Of Small- To Medium-Scale Gene Regulatory Networks, Kam D. Dahlquist, John David N. Dionisio, Ben G. Fitzpatrick, Nicole A. Anguiano, Anindita Varshneya, Britain J. Southwick, Mihir Samdarshi Sep 2016

Grnsight: A Web Application And Service For Visualizing Models Of Small- To Medium-Scale Gene Regulatory Networks, Kam D. Dahlquist, John David N. Dionisio, Ben G. Fitzpatrick, Nicole A. Anguiano, Anindita Varshneya, Britain J. Southwick, Mihir Samdarshi

Biology Faculty Works

GRNsight is a web application and service for visualizing models of gene regulatory networks (GRNs). A gene regulatory network (GRN) consists of genes, transcription factors, and the regulatory connections between them which govern the level of expression of mRNA and protein from genes. The original motivation came from our efforts to perform parameter estimation and forward simulation of the dynamics of a differential equations model of a small GRN with 21 nodes and 31 edges. We wanted a quick and easy way to visualize the weight parameters from the model which represent the direction and magnitude of the influence of …


Principles And Practices Fostering Inclusive Excellence: Lessons From The Howard Hughes Medical Institute’S Capstone Institutions, P. M. Dibartolo, L. Gregg-Jolly, D. Gross, C. A. Manduca, E. Iverson, D. B. Cooke Iii, G. K. Davis, C. Davidson, P. E. Hertz, L. Hibbard, S. K. Ireland, C. Mader, A. Pai, S. Raps, Kathleen King Siwicki, J. E. Swartz Sep 2016

Principles And Practices Fostering Inclusive Excellence: Lessons From The Howard Hughes Medical Institute’S Capstone Institutions, P. M. Dibartolo, L. Gregg-Jolly, D. Gross, C. A. Manduca, E. Iverson, D. B. Cooke Iii, G. K. Davis, C. Davidson, P. E. Hertz, L. Hibbard, S. K. Ireland, C. Mader, A. Pai, S. Raps, Kathleen King Siwicki, J. E. Swartz

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Best-practices pedagogy in science, technology, engineering, and mathematics (STEM) aims for inclusive excellence that fosters student persistence. This paper describes principles of inclusivity across 11 primarily undergraduate institutions designated as Capstone Awardees in Howard Hughes Medical Institute’s (HHMI) 2012 competition. The Capstones represent a range of institutional missions, student profiles, and geographical locations. Each successfully directed activities toward persistence of STEM students, especially those from traditionally underrepresented groups, through a set of common elements: mentoring programs to build community; research experiences to strengthen scientific skill/identity; attention to quantitative skills; and outreach/bridge programs to broaden the student pool. This paper grounds …


Review Of "A Primer Of Human Genetics" By G. Gibson, John B. Jenkins Sep 2016

Review Of "A Primer Of Human Genetics" By G. Gibson, John B. Jenkins

Biology Faculty Works

No abstract provided.


Active Learning Outside The Classroom: Implementation And Outcomes Of Peer-Led Team-Learning Workshops In Introductory Biology, Philip Kudish, Robin Shores, A. Mcclung, Lisa Smulyan , '76, Elizabeth Ann Vallen, Kathleen King Siwicki Sep 2016

Active Learning Outside The Classroom: Implementation And Outcomes Of Peer-Led Team-Learning Workshops In Introductory Biology, Philip Kudish, Robin Shores, A. Mcclung, Lisa Smulyan , '76, Elizabeth Ann Vallen, Kathleen King Siwicki

Biology Faculty Works

Study group meetings (SGMs) are voluntary-attendance peer-led team-learning workshops that supplement introductory biology lectures at a selective liberal arts college. While supporting all students’ engagement with lecture material, specific aims are to improve the success of underrepresented minority (URM) students and those with weaker backgrounds in biology. Peer leaders with experience in biology courses and training in science pedagogy facilitate work on faculty-generated challenge problems. During the eight semesters assessed in this study, URM students and those with less preparation attended SGMs with equal or greater frequency than their counterparts. Most agreed that SGMs enhanced their comprehension of biology and …


Measures Of Relative Dentary Strength In Rancho La Brea Smilodon Fatalis Over Time, Wendy J. Binder, Kassaundra S. Cervantes, Julie A. Meachen Sep 2016

Measures Of Relative Dentary Strength In Rancho La Brea Smilodon Fatalis Over Time, Wendy J. Binder, Kassaundra S. Cervantes, Julie A. Meachen

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The late Pleistocene megafaunal extinction of approximately 12,000 years ago, included the demise of Smilodon fatalis, a hypercarnivore from the Rancho La Brea deposits, which has been studied across time by looking at different deposits or pits to determine morphological size and shape changes and trends during this time. To better understand functional aspects of these changes, this study focused on a measure of jaw strength over time, which can give an indication of morphological changes within the jaw that cannot be seen using surface morphometrics. By radiographing dentaries, cortical bone can be seen, which provides an estimate of resistance …


Multitrophic Diversity Effects Of Network Degradation, Elizabeth Nichols, C. A. Peres, J. E. Hawes, S. Naeem Jul 2016

Multitrophic Diversity Effects Of Network Degradation, Elizabeth Nichols, C. A. Peres, J. E. Hawes, S. Naeem

Biology Faculty Works

Predicting the functional consequences of biodiversity loss in realistic, multitrophic communities remains a challenge. No existing biodiversity–ecosystem function study to date has simultaneously incorporated information on species traits, network topology, and extinction across multiple trophic levels, while all three factors are independently understood as critical drivers of post-extinction network structure and function. We fill this gap by comparing the functional consequences of simulated species loss both within (monotrophic) and across (bitrophic) trophic levels, in an ecological interaction network estimated from spatially explicit field data on tropical fecal detritus producer and consumers (mammals and dung beetles). We simulated trait-ordered beetle and …


Review Of "The Least Likely Man: Marshall Nirenberg And The Discovery Of The Genetic Code" By F. H. Portugal, John B. Jenkins Jun 2016

Review Of "The Least Likely Man: Marshall Nirenberg And The Discovery Of The Genetic Code" By F. H. Portugal, John B. Jenkins

Biology Faculty Works

No abstract provided.


A Potential Mate Influences Reproductive Development In Female, But Not Male, Pine Siskins, Heather E. Watts, Bruce Edley, Thomas P. Hahn Apr 2016

A Potential Mate Influences Reproductive Development In Female, But Not Male, Pine Siskins, Heather E. Watts, Bruce Edley, Thomas P. Hahn

Biology Faculty Works

The role of photoperiod in avian reproductive timing has been well studied, and we are increasingly recognizing the roles of other environmental cues such as social cues. However, few studies have evaluated the extent to which males and females of the same species respond similarly to the same type of cue. Moreover, previous studies have rarely examined how variation in the quality or nature of a given social cue might modulate its effect. Here, we examine the sensitivity of male and female pine siskins (Spinus pinus) to a potential mate as a stimulatory cue for gonadal recrudescence, and …


How Important Is A Postdoc For A Teaching Career?, Amy Cheng Vollmer, V. Balke, C. Frantz, T. E. Hanson Mar 2016

How Important Is A Postdoc For A Teaching Career?, Amy Cheng Vollmer, V. Balke, C. Frantz, T. E. Hanson

Biology Faculty Works

No abstract provided.


Distribution And Abundance Of Glucocorticoid And Mineralocorticoid Receptors Throughout The Brain Of The Great Tit (Parus Major), Rebecca A. Senft , '15, S. L. Meddle, Alexander T. Baugh Feb 2016

Distribution And Abundance Of Glucocorticoid And Mineralocorticoid Receptors Throughout The Brain Of The Great Tit (Parus Major), Rebecca A. Senft , '15, S. L. Meddle, Alexander T. Baugh

Biology Faculty Works

The glucocorticoid stress response, regulated by the hypothalamic-pituitary-adrenal (HPA) axis, enables individuals to cope with stressors through transcriptional effects in cells expressing the appropriate receptors. The two receptors that bind glucocorticoids—the mineralocorticoid receptor (MR) and glucocorticoid receptor (GR)—are present in a variety of vertebrate tissues, but their expression in the brain is especially important. Neural receptor patterns have the potential to integrate multiple behavioral and physiological traits simultaneously, including self-regulation of glucocorticoid secretion through negative feedback processes. In the present work, we quantified the expression of GR and MR mRNA throughout the brain of a female great tit (Parus major), …


Female Túngara Frogs Do Not Experience The Continuity Illusion, Alexander T. Baugh, M. J. Ryan, X. E. Bernal, A. S. Rand, M. A. Bee Feb 2016

Female Túngara Frogs Do Not Experience The Continuity Illusion, Alexander T. Baugh, M. J. Ryan, X. E. Bernal, A. S. Rand, M. A. Bee

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In humans and some non-human vertebrates, a sound containing brief silent gaps can be rendered perceptually continuous by inserting noise into the gaps. This so-called ‘continuity illusion’ arises from a phenomenon known as ‘auditory induction’ and results in the perception of complete auditory objects despite fragmentary or incomplete acoustic information. Previous studies of auditory induction in gray treefrogs (Hyla versicolor and H. chrysoscelis) have demonstrated an absence of this phenomenon. These treefrog species produce pulsatile (non-continuous) vocalizations, whereas studies of auditory induction in other taxa, including humans, often present continuous sounds (e.g., frequency-modulated sweeps). This study investigated the continuity illusion …


Getting The Hologenome Concept Right: An Eco-Evolutionary Framework For Hosts And Their Microbiomes, K. R. Theis, N. M. Dheilly, J. L. Klassen, R. M. Brucker, J. F. Baines, T. C. G. Bosch, J. F. Cryan, Scott F. Gilbert, C. J. Goodnight, E. A. Lloyd, J. Sapp, P. Vandenkoornhuyse, I. Zilber-Rosenberg, E. Rosenberg, S. R. Bordenstein Jan 2016

Getting The Hologenome Concept Right: An Eco-Evolutionary Framework For Hosts And Their Microbiomes, K. R. Theis, N. M. Dheilly, J. L. Klassen, R. M. Brucker, J. F. Baines, T. C. G. Bosch, J. F. Cryan, Scott F. Gilbert, C. J. Goodnight, E. A. Lloyd, J. Sapp, P. Vandenkoornhuyse, I. Zilber-Rosenberg, E. Rosenberg, S. R. Bordenstein

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Given the complexity of host-microbiota symbioses, scientists and philosophers are asking questions at new biological levels of hierarchical organization—what is a holobiont and hologenome? When should this vocabulary be applied? Are these concepts a null hypothesis for host-microbe systems or limited to a certain spectrum of symbiotic interactions such as host-microbial coevolution? Critical discourse is necessary in this nascent area, but productive discourse requires that skeptics and proponents use the same lexicon. For instance, critiquing the hologenome concept is not synonymous with critiquing coevolution, and arguing that an entity is not a primary unit of selection dismisses the fact that …


Principles Of Differentiation And Morphogenesis, Scott F. Gilbert, R. Rice Jan 2016

Principles Of Differentiation And Morphogenesis, Scott F. Gilbert, R. Rice

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Developmental biology is the science connecting genetics with anatomy, making sense out of both. The body builds itself from the instructions of the inherited DNA and the cytoplasmic system that interprets the DNA into genes and creates intracellular and cellular networks to generation the observable phenotype. Even ecological factors such as diet and stress may modify the DNA such that different phenotypes can be constructed from the same DNA. During the past two decades, the basic principles of development have become known; although this brief chapter cannot do them justice (see, for example, Gilbert, 2013), they cover the following: mechanisms …


Preliminary Report: A Survey Of Aggressive Behaviors In The American Coot (Fulica Americana) At Ballona Wetlands, California, Victor D. Carmona-Galindo, Mariele Anne Courtois, Kiara Cerda Jan 2016

Preliminary Report: A Survey Of Aggressive Behaviors In The American Coot (Fulica Americana) At Ballona Wetlands, California, Victor D. Carmona-Galindo, Mariele Anne Courtois, Kiara Cerda

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Understanding interspecific and intraspecific aggression is important for wildlife management and sustainability of populations. The objective of this study was to evaluate whether there is a difference in number of occurrences of interspecific aggression between American coots (Fulica americana) and mallard ducks (Anas platyrhynchos) and intraspecific aggression among American coots in the Ballona wetland habitat of Southern California. Trends in literature describe coots as highly aggressive toward other coots year-round and toward other bird species during the breeding season. Because we conducted observations outside the breeding season, we hypothesized that more instances of intraspecific aggression would …


Fibronectin Contributes To Notochord Intercalation In The Invertebrate Chordate, Ciona Intestinalis, F. Segade, C. Cota, A. Famiglietti, A. Cha, Bradley Justin Davidson , '91 Jan 2016

Fibronectin Contributes To Notochord Intercalation In The Invertebrate Chordate, Ciona Intestinalis, F. Segade, C. Cota, A. Famiglietti, A. Cha, Bradley Justin Davidson , '91

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Background: Genomic analysis has upended chordate phylogeny, placing the tunicates as the sister group to the vertebrates. This taxonomic rearrangement raises questions about the emergence of a tunicate/vertebrate ancestor. Results: Characterization of developmental genes uniquely shared by tunicates and vertebrates is one promising approach for deciphering developmental shifts underlying acquisition of novel, ancestral traits. The matrix glycoprotein Fibronectin (FN) has long been considered a vertebrate-specific gene, playing a major instructive role in vertebrate embryonic development. However, the recent computational prediction of an orthologous “vertebrate-like” Fn gene in the genome of a tunicate, Ciona savignyi, challenges this viewpoint suggesting that Fn …


A “Rule-Of-Five” Framework For Models And Modeling To Unify Mathematicians And Biologists And Improve Student Learning, Kam D. Dahlquist Jan 2016

A “Rule-Of-Five” Framework For Models And Modeling To Unify Mathematicians And Biologists And Improve Student Learning, Kam D. Dahlquist

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Despite widespread calls for the incorporation of mathematical modeling into the undergraduate biology curriculum, there is lack of a common understanding around the definition of modeling, which inhibits progress. In this paper, we extend the “Rule-of-Four,” initially used in calculus reform efforts, to a “Rule-of-Five” framework for models and modeling that is inclusive of varying disciplinary definitions of each. This unifying framework allows us to both build on strengths that each discipline and its students bring, but also identify gaps in modeling activities practiced by each discipline. We also discuss benefits to student learning and interdisciplinary collaboration.


Bolstered Physical Defences Under Nutrient-Enriched Conditions May Facilitate A Secondary Foundational Algal Species In The South Pacific, Sarah Joy Bittick Jan 2016

Bolstered Physical Defences Under Nutrient-Enriched Conditions May Facilitate A Secondary Foundational Algal Species In The South Pacific, Sarah Joy Bittick

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Humans have a long history of changing species' ranges and habitat distributions, making studies of the ecological processes that may facilitate these changes of key importance, particularly in cases where a primary foundation species is replaced by another, less desirable species. We investigated the impact of nutrients and herbivory on Turbinaria ornata, a secondary foundational macroalga that depends on and likely competes with coral, the primary foundational community. T. ornata is also rapidly expanding in range and habitat across the South Pacific. We conducted (i) a mesocosm experiment assessing relative nutrient limitation, (ii) a field experiment comparing importance of nutrients …


Nutrients Induce And Herbivores Maintain Thallus Toughness, A Structural Antiherbivory Defense In Turbinaria Ornata, Sarah Joy Bittick Jan 2016

Nutrients Induce And Herbivores Maintain Thallus Toughness, A Structural Antiherbivory Defense In Turbinaria Ornata, Sarah Joy Bittick

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The loss of coral cover, frequently driven by anthropogenic disturbances, can result in a phase shift to dominance by fleshy macroalgae, many of which contain anti-herbivore defenses. Using field surveys, a mesocosm experiment, and field experiments, we evaluate whether 2 human impacts-nutrient enrichment and reduction in herbivory-affected production and maintenance of thallus toughness, a physical defense of the brown macroalgae Turbinari ornata that has recently expanded across the South Pacific. In contrast to our expectations, there was a weak negative relationship between herbivorous fish abundance and thallus toughness This relationship was driven by greater toughness in algae collected at the …