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Evolution

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Articles 271 - 300 of 354

Full-Text Articles in Biology

Evolution And Expression Of The Lysozyme And Beta1,4-Galactosyltransferase Families In Mammals : Possible Roles In Fertilization, Jason Michael Biegel Jan 2013

Evolution And Expression Of The Lysozyme And Beta1,4-Galactosyltransferase Families In Mammals : Possible Roles In Fertilization, Jason Michael Biegel

Legacy Theses & Dissertations (2009 - 2024)

Understanding the specificity of sperm-egg recognition during mammalian fertilization has been a topic of intense study for many years, and yet the biochemical basis for this process is still largely unknown. Mammalian eggs are covered by thick glycoprotein coats, called zona pellucida (ZP), which contain glycans of varying structures that must be specifically recognized, and presumably cleaved, for fertilization to occur. Various experiments have implicated B1,4-galactosyltransferase 1 (B4GalT1) in the ability of mouse sperm to bind the ZP. Here I present evidence that additional members of the B4GalT family (specifically B4GalT3 and B4GalT4) are present on mouse and rat sperm, …


Salamander Hox Clusters Contain Repetitive Dna And Expanded Non-Coding Regions: A Typical Hox Structure For Non-Mammalian Tetrapod Vertebrates?, Stephen Randal Voss, Srikrishna Putta, John A. Walker, Jeremiah J. Smith, Nobuyasu Maki, Panagiotis A. Tsonis Jan 2013

Salamander Hox Clusters Contain Repetitive Dna And Expanded Non-Coding Regions: A Typical Hox Structure For Non-Mammalian Tetrapod Vertebrates?, Stephen Randal Voss, Srikrishna Putta, John A. Walker, Jeremiah J. Smith, Nobuyasu Maki, Panagiotis A. Tsonis

Biology Faculty Publications

Hox genes encode transcription factors that regulate embryonic and post-embryonic developmental processes. The expression of Hox genes is regulated in part by the tight, spatial arrangement of conserved coding and non-coding sequences. The potential for evolutionary changes in Hox cluster structure is thought to be low among vertebrates; however, recent studies of a few non-mammalian taxa suggest greater variation than originally thought. Using next generation sequencing of large genomic fragments (>100 kb) from the red spotted newt (Notophthalamus viridescens), we found that the arrangement of Hox cluster genes was conserved relative to orthologous regions from other vertebrates, but the …


A New Social Gene In Dictyostelium Discoideum, Chtb, Lorenzo A. Santorelli, Adam Kuspa, Gad Shaulsky, David C. Queller, Joan E. Strassmann Jan 2013

A New Social Gene In Dictyostelium Discoideum, Chtb, Lorenzo A. Santorelli, Adam Kuspa, Gad Shaulsky, David C. Queller, Joan E. Strassmann

Biology Faculty Research

BACKGROUND:

Competitive social interactions are ubiquitous in nature, but their genetic basis is difficult to determine. Much can be learned from single gene knockouts in a eukaryote microbe. The mutants can be competed with the parent to discern the social impact of that specific gene. Dictyostelium discoideum is a social amoeba that exhibits cooperative behavior in the construction of a multicellular fruiting body. It is a good model organism to study the genetic basis of cooperation since it has a sequenced genome and it is amenable to genetic manipulation. When two strains of D. discoideum are mixed, a cheater strain …


Structure, Dynamics, And Evolution Of The Intrinsically Disordered P53 Transactivation Domain, Wade Michael Borcherds Jan 2013

Structure, Dynamics, And Evolution Of The Intrinsically Disordered P53 Transactivation Domain, Wade Michael Borcherds

USF Tampa Graduate Theses and Dissertations

in numerous disease states, including cancers and neurodegenerative diseases. All proteins are dynamic in nature, occupying a range of conformational flexibilities. This inherent flexibility is required for their function, with ordered proteins and IDPs representing the least flexible, and most flexible, respectively. As such IDPs possess little to no stable tertiary or secondary structure, they instead form broad ensembles of heterogeneous structures, which fluctuate over multiple time scales. Although IDPs often lack stable secondary structure they can assume a more stable structure in the presence of their binding partners in a coupled folding binding reaction.

The phenomenon of the dynamic …


The Phylogenetics Of Tachinidae (Insecta: Diptera) With An Emphasis On Subfamily Structure, Daniel J. Davis Jan 2013

The Phylogenetics Of Tachinidae (Insecta: Diptera) With An Emphasis On Subfamily Structure, Daniel J. Davis

Browse all Theses and Dissertations

The parasitoid flies of the Tachinidae family are an important and diverse (>10,000 species) lineage of insects. However, tachinids are not well studied partially due to their confusing classification and taxonomy. DNA sequences were obtained from twenty tribal representatives of Tachinidae, along with eight outgroups in order to phylogenetically reconstruct the superfamilial, subfamilial and tribal relationships of Tachinidae. Seven gene regions of six genes (18S, 28S, COI, CAD, Ef1a, and TPI) were sequenced for each taxon (6214 bp total). Both maximum likelihood and Bayesian methods were used to infer phylogenies. The Sarcophagidae and Oestridae were usually reconstructed as monophyletic. …


Transcendental Thermodynamics, Richard E. Morel, George Fleck Jun 2012

Transcendental Thermodynamics, Richard E. Morel, George Fleck

Kahn Institute Projects

Thermodynamics is often viewed as a narrow, introspective discipline, trapped by its origins in the 18th and 19th centuries. By dramatic contrast, we show that the Fourth Law of Thermodynamics provides explanations and interpretations of all natural events, extending across artificial boundaries of tradition- al academic disciplines. The Fourth Law of Thermodynamics states that far-from-equilibrium systems increase entropy at the maximum rate available to them. This broadly inclusive paradigm applies to systems from molecules, to organisms, to the biosphere. The Fourth Law is the Law of Evolution. All systems that communicate with their environment exhibit self-organization and self-optimization, enabling the …


Natural Selection And Moral Sentiment: Evolutionary Biology's Challenge To Moral Philosophy, Charles W. Wright May 2012

Natural Selection And Moral Sentiment: Evolutionary Biology's Challenge To Moral Philosophy, Charles W. Wright

Headwaters

No abstract provided.


Evolution And Biogeography Of Fire-Eye Antbirds (Genus Pyriglena): Insights From Molecules And Songs, Marcos Maldonado Coelho May 2012

Evolution And Biogeography Of Fire-Eye Antbirds (Genus Pyriglena): Insights From Molecules And Songs, Marcos Maldonado Coelho

Dissertations

The importance of climatic and geologic factors as drivers of population differentiation and speciation in the Neotropical region has long been appreciated. However, many questions remain regarding their roles underlying the processes and patterns of diversification. Studies conducted in distinct regions containing a suite of geological and ecological conditions constitute ideal scenarios to assess the role of Pleistocene climatic changes, rivers, and mountain building as historical diversification mechanisms. In chapters 1 and 2, I used an integrative approach combining molecular phylogenetics, phylogeography and population genetics to elucidate the importance of climatic and geological factors as engines of diversification. I focused …


Drag Reduction In Wave-Swept Macroalgae: Alternative Strategies And New Predictions, Patrick T. Martone, Laurie Kost, Michael L. Boller May 2012

Drag Reduction In Wave-Swept Macroalgae: Alternative Strategies And New Predictions, Patrick T. Martone, Laurie Kost, Michael L. Boller

Biology Faculty/Staff Publications

Premise of the study: Intertidal macroalgae must resist extreme hydrodynamic forces imposed by crashing waves. How does frond flexibility mitigate drag, and how does flexibility affect predictions of drag and dislodgement in the field? Methods: We characterized flexible reconfiguration of six seaweed species in a recirculating water flume, documenting both shape change and area reduction as fronds reorient. We then used a high-speed gravity-accelerated water flume to test our ability to predict drag under waves based on extrapolations of drag recorded at slower speeds. We compared dislodgement forces to drag forces predicted from slow- and high-speed data to generate new …


Variation And Organization In Social Behavior: Infectious Disease And Human Intergroup Conflict And Warfare; And The Organization Of Foraging Behavior In Harvester Ants, Kenneth Letendre May 2012

Variation And Organization In Social Behavior: Infectious Disease And Human Intergroup Conflict And Warfare; And The Organization Of Foraging Behavior In Harvester Ants, Kenneth Letendre

Biology ETDs

Social behavior is an important contributor to the success of widely distributed animal taxa, including such distantly related taxa as humans and ants. There is variation in the features and organization of social systems based on ecological constraints and goals, as these alter the costs and benefits of social behaviors, and select for different optimal behaviors for social groups in different environments. I present two bodies of research: an effort to explain geographic variation in the frequency and intensity of human civil conflict; and an effort to describe and model the foraging behavior of colonies of harvester ants of the …


Proteins: Form And Function, Roy D. Sleator Mar 2012

Proteins: Form And Function, Roy D. Sleator

Department of Biological Sciences Publications

An overwhelming array of structural variants has evolved from a comparatively small number of protein structural domains; which has in turn facilitated an expanse of functional derivatives. Herein, I review the primary mechanisms which have contributed to the vastness of our existing, and expanding, protein repertoires. Protein function prediction strategies, both sequence and structure based, are also discussed and their associated strengths and weaknesses assessed.


The Chicken Challenge – What Contemporary Studies Of Fowl Mean For Science And Ethics, Carolynn L. Smith, Jane Johnson Feb 2012

The Chicken Challenge – What Contemporary Studies Of Fowl Mean For Science And Ethics, Carolynn L. Smith, Jane Johnson

Between the Species

Studies with captive fowl have revealed that they possess greater cognitive capacities than previously thought. We now know that fowl have sophisticated cognitive and communicative skills, which had hitherto been associated only with certain primates. Several theories have been advanced to explain the evolution of such complex behavior. Central to these theories is the enlargement of the brain in species with greater mental capacities. Fowl present us with a conundrum, however, because they show the behaviors anticipated by the theories but do not have the expected changes in the brain. Consequently fowl present two challenges of interest to us here. …


Evolution Of Plant Sucrose Uptake Transporters, Anke Reinders, Alicia B. Sivitz, John M. Ward Feb 2012

Evolution Of Plant Sucrose Uptake Transporters, Anke Reinders, Alicia B. Sivitz, John M. Ward

Dartmouth Scholarship

In angiosperms, sucrose uptake transporters (SUTs) have important functions especially in vascular tissue. Here we explore the evolutionary origins of SUTs by analysis of angiosperm SUTs and homologous transporters in a vascular early land plant, Selaginella moellendorffii, and a non-vascular plant, the bryophyte Physcomitrella patens, the charophyte algae Chlorokybus atmosphyticus, several red algae and fission yeast, Schizosaccharomyces pombe. Plant SUTs cluster into three types by phylogenetic analysis. Previous studies using angiosperms had shown that types I and II are localized to the plasma membrane while type III SUTs are associated with vacuolar membrane. SUT homologs were …


Divergent Functions Of The Myotubularin (Mtm) Homologs Atmtm1 And Atmtm2 In Arabidopsis Thaliana: Evolution Of The Plant Mtm Family, Yong Ding, Ivan Ndamukong, Yang Zhao, Yuannan Xia, Jean-Jack Riethoven, David R. Jones, Nullin Divecha, Zoya Avramova Jan 2012

Divergent Functions Of The Myotubularin (Mtm) Homologs Atmtm1 And Atmtm2 In Arabidopsis Thaliana: Evolution Of The Plant Mtm Family, Yong Ding, Ivan Ndamukong, Yang Zhao, Yuannan Xia, Jean-Jack Riethoven, David R. Jones, Nullin Divecha, Zoya Avramova

School of Biological Sciences: Faculty Publications

Myotubularin and myotubularin-related proteins are evolutionarily conserved in eukaryotes. Defects in their function result in muscular dystrophy, neuronal diseases, and leukemia in humans. In contrast to the animal lineage, where genes encoding both active and inactive myotubularins (phosphoinositide 3-phosphatases) have appeared and proliferated in the basal metazoan group, myotubularin genes are not found in the unicellular relatives of green plants. However, they are present in land plants encoding proteins highly similar to the active metazoan enzymes. Despite their remarkable structural conservation, plant and animal myotubularins have significantly diverged in their functions. While loss of myotubularin function causes severe disease phenotypes …


Evolving Possibilities: Postembryonic Axial Elongation In Salamanders With Biphasic (Eurcyea Cirrigera, Eurycea Longicauda, Eurycea Quadridigitata) And Paedomorphic Life Cycles (Eurycea Nana And Ambystoma Mexicanum), Janet L. Vaglia, Kurt White '09, Alison Case '09 Jan 2012

Evolving Possibilities: Postembryonic Axial Elongation In Salamanders With Biphasic (Eurcyea Cirrigera, Eurycea Longicauda, Eurycea Quadridigitata) And Paedomorphic Life Cycles (Eurycea Nana And Ambystoma Mexicanum), Janet L. Vaglia, Kurt White '09, Alison Case '09

Biology Faculty publications

Typically, the number of vertebrae an organism will have postembryonically is determined during embryogenesis via the development of paired somites. Our research investigates the phenomenon of postembryonic vertebral addition in salamander tails. We describe body and tail growth and patterns of postsacral vertebral addition and elongation in context with caudal morphology for four plethodontids ( Eurycea) and one ambystomatid. Eurycea nana and Ambystoma mexicanum have paedomorphic life cycles; Eurcyea cirrigera, Eurycea longicauda and Eurycea quadridigitata are biphasic. Specimens were collected, borrowed and/or purchased, and cleared and stained for bone and cartilage. Data collected include snout-vent length (SVL), tail length (TL), …


Intra And Interhost Dynamics Shaping Arbovirus Adaptation And Evolution, Alexander T. Ciota Jan 2012

Intra And Interhost Dynamics Shaping Arbovirus Adaptation And Evolution, Alexander T. Ciota

Legacy Theses & Dissertations (2009 - 2024)

Arthropod-borne viruses (arboviruses), which are predominately mosquito-borne and almost exclusively RNA viruses, are maintained in nature in complex transmission cycles involving blood sucking invertebrates and vertebrate hosts. Although over 120 arboviruses are human pathogens responsible for causing a significant and expanding global health burden, a detailed understanding of the complex interactions between these pathogens and their hosts, particularly invertebrate hosts, is lacking. Defining these interactions is necessary if we are to understand the selective pressures and, therefore, evolutionary, adaptive, and epidemiological potential of arboviruses. This requires experimental infection and evolution studies, particularly in vivo, with natural hosts. The results presented …


Analysis Of A Wound-Induced Gene Family In Glycine Max, Gena Robertson Jan 2012

Analysis Of A Wound-Induced Gene Family In Glycine Max, Gena Robertson

Masters Theses

Gene families in plants are important in understanding genome evolution indicating when and where genome duplications and segmental duplications occurred as well as subsequent divergence and subfunctionalization. A gene family in Glycine max that encodes a WI12 protein, wound-induced protein, was found to consist of ten genes on five chromosomes. Wound-induced proteins are activated in response to wounding in plants, and the WI12 protein in particular is thought to be involved in cell wall modifications at the wound site. A variety of bioinformatics tools have been used to analyze the expansion of this family in soybean as well as identify …


Electrosensory Ampullary Organs Are Derived From Lateral Line Placodes In Bony Fishes, Melissa S. Modrell, William E. Benis, R. Glenn Northcutt, Marcus C. Davis, Clare V.H. Baker Oct 2011

Electrosensory Ampullary Organs Are Derived From Lateral Line Placodes In Bony Fishes, Melissa S. Modrell, William E. Benis, R. Glenn Northcutt, Marcus C. Davis, Clare V.H. Baker

Faculty Articles

Electroreception is an ancient subdivision of the lateral line sensory system, found in all major vertebrate groups (though lost in frogs, amniotes and most ray-finned fishes). Electroreception is mediated by 'hair cells' in ampullary organs, distributed in fields flanking lines of mechanosensory hair cell-containing neuromasts that detect local water movement. Neuromasts, and afferent neurons for both neuromasts and ampullary organs, develop from lateral line placodes. Although ampullary organs in the axolotl (a representative of the lobe-finned clade of bony fishes) are lateral line placode-derived, non-placodal origins have been proposed for electroreceptors in other taxa. Here we show morphological and molecular …


Mammalian Diversification Across The Holarctic: Spatiotemporal Evolution In Response To Environmental Change, Andrew G. Hope Jul 2011

Mammalian Diversification Across The Holarctic: Spatiotemporal Evolution In Response To Environmental Change, Andrew G. Hope

Biology ETDs

The primary focus in this dissertation is on the processes of environmental change that drive evolution. We are currently witnessing unparalleled changes in climate and associated changes in biotic communities. With a growing understanding that climate and habitat change, coupled with natural variability, will have an increased influence on biota into the future, it is our responsibility to learn how best to manage and conserve the Earths natural resources. Among other things, this will require a firmer understanding of biodiversity, life histories, evolutionary relationships among species, and community dynamics over multiple species. One method of understanding how species will respond …


Determining The Composition Of The Dwelling Tubes Of Antarctic Pterobranchs, Lukasz J. Sewera Apr 2011

Determining The Composition Of The Dwelling Tubes Of Antarctic Pterobranchs, Lukasz J. Sewera

Honors Projects

Pterobranchs are a group of marine invertebrates within the Hemichordata, which share characteristics with both chordates and echinoderms.  Pterobranchs live in colonies of secreted tubes, coenicia, which are composed of a gelatinous material of unknown composition.  Visually, the tubes appear similar to the tunic of tunicates, a group of invertebrates within the Chordata. The nonproteinaceous tunic of tunicates is composed of cellulose, which is unusual.  The goal of this study was to determine the composition of the pterobranch coenicium. Some aspects of pterobranch phylogeny are still unclear even after multiple molecular and morphological studies.  Identification of any new shared characteristics …


Evolution And Personal Religious Belief: Christian University Biology-Related Majors’ Search For Reconciliation, Mark Winslow, John Staver, Lawrence C. Scharmann Jan 2011

Evolution And Personal Religious Belief: Christian University Biology-Related Majors’ Search For Reconciliation, Mark Winslow, John Staver, Lawrence C. Scharmann

Department of Teaching, Learning, and Teacher Education: Faculty Publications

The goal of this study was to explore Christian biology-related majors’ perceptions of conflicts between evolution and their religious beliefs. This naturalistic study utilized a case study design of 15 undergraduate biology-related majors at or recent biology-related graduates from a mid-western Christian university. The broad sources of data were interviews, course documents, and observations. Outcomes indicate that most participants were raised to believe in creationism, but came to accept evolution through evaluating evidence for evolution, negotiating the literalness of Genesis, recognizing evolution as a non-salvation issue, and observing professors as Christian role models who accept evolution. This study lends heuristic …


The Burden Of Motherhood: The Effect Of Reproductive Load On Female Lizard Locomotor, Foraging, And Social Behavior, Michele A. Johnson, J. L. Caton, R. E. Cohen, J. R. Vandecar, J. Wade Dec 2010

The Burden Of Motherhood: The Effect Of Reproductive Load On Female Lizard Locomotor, Foraging, And Social Behavior, Michele A. Johnson, J. L. Caton, R. E. Cohen, J. R. Vandecar, J. Wade

Biology Faculty Research

The costs of reproduction, involving demands associated with both current and future reproductive efforts, may place a substantial burden on females. However, animals may minimize these costs by modifying their behavior across the reproductive cycle. We examined the effects of reproductive load on three types of behavior (locomotion, foraging, and social displays) in green anole lizards (Anolis carolinensis) by comparing egg, follicle, and oviduct mass and volume with field observational data. We found that female locomotor and social display behaviors decreased as reproductive load increased, suggesting behavioral modification in these traits, but we detected no relationship between foraging and …


Historical Biogeography Of Velvet Ants (Hymenoptera: Mutillidae) In The North American Deserts And Arid Lands, Joseph S. Wilson Dec 2010

Historical Biogeography Of Velvet Ants (Hymenoptera: Mutillidae) In The North American Deserts And Arid Lands, Joseph S. Wilson

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

For centuries, scientists have been intrigued by the high amount of biodiversity that is found in the deserts of North America. Recently, several studies have investigated the causes of the high diversity found in desert-dwelling mammals, reptiles, and amphibians. These studies have found that many of these organisms seem to have diversified in response to the same historical events. Little work has been done, however, on diverse desert-dwelling insect groups. In this dissertation, I investigate the patterns of genetic diversity in four groups of nocturnal wasps called velvet ants. I compare the patterns of genetic diversity to the historical events …


Role Of Eukaryotic Sel-1 Like Repeat Containing Genes In Helicobacter Pylori Evolution And Pathogenesis., Kalyani Putty Dec 2010

Role Of Eukaryotic Sel-1 Like Repeat Containing Genes In Helicobacter Pylori Evolution And Pathogenesis., Kalyani Putty

Electronic Theses and Dissertations

Background: Helicobacter pylori (Hp) establishes life-long gastric infection in billions of humans, and is often responsible for diseases such as peptic ulcer and gastric cancer. Cumulative actions of genetic drift and natural selection over several millennia sculpted the present Hp population structure, which is characterized by extreme genetic diversity and striking geographic clustering of genotypes. Natural selection is more commonly imprinted in DNA sequences of Hp proteins that interact with host components; however, in most instances biological relevance of selection during Hp infection remains unknown. Here, I attempted to elucidate the consequence of natural selection in two different contexts: (1) …


Robert Koch, Creation, And The Specificity Of Germs, Alan L. Gillen, Douglas Oliver, Frank Sherwin Apr 2010

Robert Koch, Creation, And The Specificity Of Germs, Alan L. Gillen, Douglas Oliver, Frank Sherwin

Faculty Publications and Presentations

Microbiology is dominated by evolution today. Just look at any text, journal article, or the topics presented at professional scientific meetings. Darwin is dominant.

Microbiology is dominated by evolution today. Just look at any text, journal article, or the topics presented at professional scientific meetings. Darwin is dominant. Many argue that “nothing in biology makes sense except in the light of evolution” (Dobzhansky 1973). But it was not always this way. In fact, a review of the major founders of microbiology has shown that they were creationists.1 We would argue that a better idea thanevolution and one of much …


Investigating Instructors' Conceptions Of Evolution Through The Development Of The Classroom Test Of Evolutionary Reasoning, Patricia Eileen Palko Jan 2010

Investigating Instructors' Conceptions Of Evolution Through The Development Of The Classroom Test Of Evolutionary Reasoning, Patricia Eileen Palko

Electronic Theses and Dissertations

In order to assess the evolutionary understanding of high school biology teachers, an instrument entitled the Classroom Test of Evolutionary Reasoning (CTER) was developed. Content, response process, relations to another variable (the Conceptual Inventory of Natural Selection, or CINS), and internal structure evidence were compiled. The second version of the CTER was found to have adequate reliability and validity estimates to allow it to continue to be used as a measurement tool for an understanding of evolution. When assessing a sample of teachers (n = 724), the mean score was 6.35 out of a possible 13 points. The sample was …


Adaptive Evolution And Inherent Tolerance To Extreme Thermal Environments, Jennifer Cox, Alyxandria Schubert, Michael Travisano, Catherine Putonti Jan 2010

Adaptive Evolution And Inherent Tolerance To Extreme Thermal Environments, Jennifer Cox, Alyxandria Schubert, Michael Travisano, Catherine Putonti

Bioinformatics Faculty Publications

Background

When introduced to novel environments, the ability for a species to survive and rapidly proliferate corresponds with its adaptive potential. Of the many factors that can yield an environment inhospitable to foreign species, phenotypic response to variation in the thermal climate has been observed within a wide variety of species. Experimental evolution studies using bacteriophage model systems have been able to elucidate mutations, which may correspond with the ability of phage to survive modest increases/decreases in the temperature of their environment.

Results

Phage ΦX174 was subjected to both elevated (50°C) and extreme (70°C+) temperatures for anywhere from a few …


Introduction: Protistan Biology, Horizontal Gene Transfer, And Common Descent Uncover Faulty Logic In Intelligent Design, Avelina Espinosa Jan 2010

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 …


Biogeography And Diversification In The Neotropics: Testing Macroevolutionary Hypotheses Using Molecular Phylogenetic Data, Juan Manuel Daza Rojas Jan 2010

Biogeography And Diversification In The Neotropics: Testing Macroevolutionary Hypotheses Using Molecular Phylogenetic Data, Juan Manuel Daza Rojas

Electronic Theses and Dissertations

Lineage diversification in the Neotropics is an interesting topic in evolutionary biology and one of the least understood. The complexity of the region precludes generalizations regarding the historical and evolutionary processes responsible for the observed high diversity. Here, I use molecular data to infer evolutionary relationships and test hypotheses of current taxonomy, species boundaries, speciation and biogeographic history in several lineages of Neotropical snakes. I comprehensively sampled a widely distributed Neotropical colubrid snake and Middle American pitvipers and combined my data with published sequences. Within the colubrid genus Leptodeira, mitochondrial and nuclear markers revealed a phylogeograhic structure that disagrees with …


Species Delimitation In Lemurs: Multiple Genetic Loci Reveal Low Levels Of Species Diversity In The Genus Cheirogaleus, Linn F. Groeneveld, David W. Weisrock, Rodin M. Rasoloarison, Anne D. Yoder, Peter M. Kappeler Feb 2009

Species Delimitation In Lemurs: Multiple Genetic Loci Reveal Low Levels Of Species Diversity In The Genus Cheirogaleus, Linn F. Groeneveld, David W. Weisrock, Rodin M. Rasoloarison, Anne D. Yoder, Peter M. Kappeler

Biology Faculty Publications

BACKGROUND: Species are viewed as the fundamental unit in most subdisciplines of biology. To conservationists this unit represents the currency for global biodiversity assessments. Even though Madagascar belongs to one of the top eight biodiversity hotspots of the world, the taxonomy of its charismatic lemuriform primates is not stable. Within the last 25 years, the number of described lemur species has more than doubled, with many newly described species identified among the nocturnal and small-bodied cheirogaleids. Here, we characterize the diversity of the dwarf lemurs (genus Cheirogaleus) and assess the status of the seven described species, based on phylogenetic and …