Open Access. Powered by Scholars. Published by Universities.®

Population Biology Commons

Open Access. Powered by Scholars. Published by Universities.®

1399 Full-Text Articles 2697 Authors 135927 Downloads 88 Institutions

All Articles in Population Biology

Faceted Search

1399 full-text articles. Page 1 of 37.

Development Of Genomic Resources For The Evaluation Of Red Snapper, An Emerging Species Candidate For Marine Aquaculture And Stock Enhancement, Adrienne Elise Norrell 2016 University of Southern Mississippi

Development Of Genomic Resources For The Evaluation Of Red Snapper, An Emerging Species Candidate For Marine Aquaculture And Stock Enhancement, Adrienne Elise Norrell

Master's Theses

The northern red snapper (Lutjanus campechanus) is a highly targeted reef fish candidate for marine aquaculture and stock enhancement in the southern United States. This work aimed to develop genomic resources for the genetic management of aquaculture programs and to investigate population structure using high-throughput sequencing technologies. Eighty-four new microsatellite markers were developed through screening of Illumina paired-end sequencing reads. Microsatellite loci and Single Nucleotide Polymorphisms (SNPs) generated through Restriction Site Associated DNA (RAD) sequencing were assayed in 5 outbred full-sib families to construct a high-density linkage map of the red snapper genome. The map consists of 7,964 markers ...


Short-Term Water Potential Fluctuations And Eggs Of The Red-Eared Slider Turtle (Trachemys Scripta Elegans), John K. Tucker, Gary L. Paukstis, Fredric J. Janzen 2016 Illinois Natural History Survey

Short-Term Water Potential Fluctuations And Eggs Of The Red-Eared Slider Turtle (Trachemys Scripta Elegans), John K. Tucker, Gary L. Paukstis, Fredric J. Janzen

Fredric Janzen

We exposed eggs of the red-eared slider turtle (Trachemys scripta elegans) to short duration (i.e., 48 hours) changes in water potential at two embryonic ages (20 and 40 days). Survivorship to hatching did not differ by substrate water potential or among treatments. Net change in egg mass, a measure of net water exchange between the egg and substrate, was affected by treatments. However, treatments had no effect on hatchling mass, carcass mass, yolk mass, or incubation period. Eggs and embryos are able to exploit beneficial short-term increases in water potential and withstand adverse ones.


Phenotypic And Fitness Consequences Of Maternal Nest-Site Choice Across Multiple Early Life Stages, Timothy S. Mitchell, Daniel A. Warner, Fredric J. Janzen 2016 Iowa State University

Phenotypic And Fitness Consequences Of Maternal Nest-Site Choice Across Multiple Early Life Stages, Timothy S. Mitchell, Daniel A. Warner, Fredric J. Janzen

Fredric Janzen

Identifying the relative contributions of genetic, maternal, and environmental factors to phenotypic variation is critical for evaluating the evolutionary potential of fitness-related traits. We employed a novel two-step cross-fostering experiment to quantify the relative contributions of clutch (i.e., maternal identity) and maternally chosen nest sites to phenotypic variation during three early life stages (incubation, hibernation, dispersal) of the painted turtle (Chrysemys picta). By translocating eggs between nests in the field, we demonstrated that both clutch and nest site contribute to phenotypic variation at hatching. Because hatchling C. pictahibernate inside nests, we performed a second cross-foster to decouple the ...


Modeling The Effects Of Climate Change–Induced Shifts In Reproductive Phenology On Temperature-Dependent Traits, Rory S. Telemeco, Karen C. Abbott, Fredric J. Janzen 2016 Iowa State University

Modeling The Effects Of Climate Change–Induced Shifts In Reproductive Phenology On Temperature-Dependent Traits, Rory S. Telemeco, Karen C. Abbott, Fredric J. Janzen

Fredric Janzen

By altering phenology, organisms have the potential to match life-history events with suitable environmental conditions. Because of this, phenological plasticity has been proposed as a mechanism whereby populations might buffer themselves from climate change. We examine the potential buffering power of advancing one aspect of phenology, nesting date, on sex ratio in painted turtles (Chrysemys picta), a species with temperature-dependent sex determination. We developed a modified constant temperature equivalent model that accounts for the effect of the interaction among climate change, oviposition date, and seasonal thermal pattern on temperature during sexual differentiation and thus on offspring sex ratio. Our results ...


Laboratory Survivorship Of Aerially Exposed Pond Snails (Physella Integra) From Illinois, John K. Tucker, Fredric J. Janzen, Gary L. Paukstis 2016 Illinois Natural History Survey

Laboratory Survivorship Of Aerially Exposed Pond Snails (Physella Integra) From Illinois, John K. Tucker, Fredric J. Janzen, Gary L. Paukstis

Fredric Janzen

Many aquatic snails occupy ephemeral habitats that are occasionally subjected to severe environmental conditions. To investigate the physiological capacity of these animals to resist extreme environmental changes, we aerially exposed aquatic pond snails (Physella integra) to temperatures of 5°C and 20°C for 6, 8, 12, 24, 36, 48, and 60 hours. Survivorship varied with temperature and exposure times. At 20°C, survivorship was 0% for snails aerially exposed for 24 hours or longer. At 5°C, 0% survivorship was attained at 60 hours exposure. Sensitivity to aerial exposure was related to shell size of individuals, with larger specimens ...


Phylogenetics: Which Was First, Tsd Or Gsd?, Fredric J. Janzen, J. G. Krenz 2016 Iowa State University

Phylogenetics: Which Was First, Tsd Or Gsd?, Fredric J. Janzen, J. G. Krenz

Fredric Janzen

The basic challenge of evolutionary biology is to explain variation or the lack thereof, be it phenotypic, genetic, phy· logenetic, spatial, temporal, and so on. To illustrate, one gross generalization is that phenotypic traits we think of as being very important to organisms tend to be highly conserved (e.g .. binocular vision in vertebrates). probably because the genomic and developmental underpinnings are essentially fiXed. Thus, one striking feature about sex-determining mechanisms (SDMs), a fundamental aspect of sexual or· ganisms, is the enormous variety (Bull1983).


Experimental Analysis Of An Early Life-History Stage: Selection On Size Of Hatchling Turtles, Fredric J. Janzen, John K. Tucker, Gary L. Paukstis 2016 Iowa State University

Experimental Analysis Of An Early Life-History Stage: Selection On Size Of Hatchling Turtles, Fredric J. Janzen, John K. Tucker, Gary L. Paukstis

Fredric Janzen

Life-history evolution in short-lived organisms has been investigated extensively, but little is known empirically about the causes of the different life-history strategies of long-lived organisms. To explore this issue, we conducted experiments to evaluate natural selection acting on key traits during an important life-history stage of the red-eared slider turtle (Trachemys scripta elegans). We reared eggs from 56 females in a seminatural common environment and released 356 of the resulting hatchlings in four replicates at a natural nesting area to assess offspring recapture probability as a measure of survivorship during the post-emergence migration. Larger body size of hatchling turtles was ...


Impact Of Nest-Site Selection On Nest Success And Nest Temperature In Natural And Disturbed Habitats, Jason J. Kolbe, Fredric J. Janzen 2016 Iowa State University

Impact Of Nest-Site Selection On Nest Success And Nest Temperature In Natural And Disturbed Habitats, Jason J. Kolbe, Fredric J. Janzen

Fredric Janzen

Nest-site selection behavior is a maternal effect that contributes to offspring survival and variation in offspring phenotypes that are subject to natural selection. We investigated nest-site selection and its consequences in the snapping turtle, Chelydra serpentina, in northwestern Illinois. We evaluated nest-site selection at both the microhabitat and habitat patch levels. Turtles selected nest sites with shorter vegetation, more open sand, and fewer cacti than random locations. These microhabitat characteristics described sandy patches where both nest density and success were higher compared to grassy patches in 1999. We subsequently investigated nest-site selection within two discrete subdivisions of the study area ...


Hydric Conditions During Incubation Influence Phenotypes Of Neonatal Reptiles In The Field, Brooke L. Bodensteiner, Timothy S. Mitchell, Jeramie T. Strickland, Fredric J. Janzen 2016 Iowa State University

Hydric Conditions During Incubation Influence Phenotypes Of Neonatal Reptiles In The Field, Brooke L. Bodensteiner, Timothy S. Mitchell, Jeramie T. Strickland, Fredric J. Janzen

Fredric Janzen

  1. Phenotypic variation is strongly impacted by environmental conditions experienced during development. Substantial laboratory research has shown that reptiles with flexible-shelled eggs are particularly sensitive to hydric conditions, yet research on nests in the wild is sparse.
  2. In this 2-year field experiment, we explore the influence of hydric conditions during incubation on phenotypic traits of hatchling painted turtles (Chrysemys picta). Using a split-clutch design, we created two artificial nests adjacent to each maternally selected nest site. Half the eggs incubated in a nest that received regular supplemental watering, while the control nest was exposed to natural precipitation only.
  3. Our results suggest ...


Climate Change And Temperature‐Dependent Sex Determination: Can Individual Plasticity In Nesting Phenology Prevent Extreme Sex Ratios?, Lisa E. Schwanz, Fredric J. Janzen 2016 Iowa State University

Climate Change And Temperature‐Dependent Sex Determination: Can Individual Plasticity In Nesting Phenology Prevent Extreme Sex Ratios?, Lisa E. Schwanz, Fredric J. Janzen

Fredric Janzen

Under temperature-dependent sex determination (TSD), temperatures experienced by embryos during development determine the sex of the offspring. Consequently, populations of organisms with TSD have the potential to be strongly impacted by climatic warming that could bias offspring sex ratio, a fundamental demographic parameter involved in population dynamics. Moreover, many taxa with TSD are imperiled, so research on this phenomenon, particularly long-term field study, has assumed great urgency. Recently, turtles with TSD have joined the diverse list of taxa that have demonstrated population- level changes in breeding phenology in response to recent climate change. This raises the possibility that any adverse ...


Counterintuitive Density-Dependent Growth In A Long-Lived Vertebrate After Removal Of Nest Predators, Ricky-John Spencer, Fredric J. Janzen, Michael B. Thompson 2016 Iowa State University

Counterintuitive Density-Dependent Growth In A Long-Lived Vertebrate After Removal Of Nest Predators, Ricky-John Spencer, Fredric J. Janzen, Michael B. Thompson

Fredric Janzen

Examining the phenotypic and genetic underpinnings of life-history variation in long-lived organisms is central to the study of life-history evolution. Juvenile growth and survival are often density dependent in reptiles, and theory predicts the evolution of slow growth in response to low resources (resource-limiting hypothesis), such as under densely populated conditions. However, rapid growth is predicted when exceeding some critical body size reduces the risk of mortality (mortality hypothesis). Here we present results of paired, large-scale, five-year field experiments to identify causes of variation in individual growth and survival rates of an Australian turtle (Emydura macquarii) prior to maturity. To ...


Does Life History Affect Molecular Evolutionary Rates?, Gerardo A. Cordero, Fredric Janzen 2016 Iowa State University

Does Life History Affect Molecular Evolutionary Rates?, Gerardo A. Cordero, Fredric Janzen

Fredric Janzen

The molecular evolutionary rate measures the frequency with which DNA or protein sequence mutations are fixed (i.e., shared by most individuals) in a population. On the other hand, the mutation rate refers to the amount of change in a DNA or protein sequence for a given unit of time. These two intrinsically related processes have been key to our basic understanding of molecular evolution. For example, the molecular clock theory (Zuckerkandl & Pauling 1962) predicts an increase in fixed amino acid mutations of protein sequences as a function of time. The molecular evolutionary rate is then expected to be constant ...


Climate And Predation Dominate Juvenile And Adult Recruitment In A Turtle With Temperature-Dependent Sex Determination, Lisa E. Schwanz, Ricky-John Spencer, Rachel M. Bowden, Fredric J. Janzen 2016 Iowa State University

Climate And Predation Dominate Juvenile And Adult Recruitment In A Turtle With Temperature-Dependent Sex Determination, Lisa E. Schwanz, Ricky-John Spencer, Rachel M. Bowden, Fredric J. Janzen

Fredric Janzen

Conditions experienced early in life can influence phenotypes in ecologically important ways, as exemplified by organisms with environmental sex determination. For organisms with temperature-dependent sex determination (TSD), variation in nest temperatures induces phenotypic variation that could impact population growth rates. In environments that vary over space and time, how does this variation influence key demographic parameters (cohort sex ratio and hatchling recruitment) in early life stages of populations exhibiting TSD? We leverage a 17-year data set on a population of painted turtles, Chrysemys picta, to investigate how spatial variation in nest vegetation cover and temporal variation in climate influence early ...


Evolutionary Ecology Of Weeds, 1st & 2nd Editions, Jack Dekker 2016 Retired: Iowa State University-University of Guelph-Michigan State University

Evolutionary Ecology Of Weeds, 1st & 2nd Editions, Jack Dekker

Jack Dekker

2nd Edition, July 2016.  Evolutionary Ecology of Weeds is the story of WHAT, WHY and HOW some plant species invade and occupy habitats ripe for exploitation.  The nature of weeds is the evolution of adaptive traits for seizing and exploiting locally available opportunity.  Weeds are the consequence of human disturbance which creates opportunity spacetime, leaving unused resources eager for invasion by weeds.  The nature of weeds is the story of us, humans.  We created highly successful wild-crop-weed complexes that resist control.  We created them by channeling natural selection, the driver of biological change.  Plants invade by dispersing, colonizing, reproducing and ...


The North American Grouse: Their Biology And Behavior, Paul A. Johnsgard 2016 University of Nebraska-Lincoln

The North American Grouse: Their Biology And Behavior, Paul A. Johnsgard

Zea E-Books

The ten currently recognized species of grouse in North America have played an important role in America’s history, from the famous but ill-fated heath hen, a primary source of meat for the earliest New England immigrants, to the ruffed grouse, currently one of the most abundant and soughtafter upland game birds in more than 40 states and provinces. This book summarizes the ecology, reproductive biology, and social behavior of all ten of the extant North American grouse species. It also describes the current status of grouse populations, some of which are perilously close to extinction. The social behavior of ...


Anticipating Elimination Of Mosquito-Borne Diseases, Suzanne M. O'Regan, Jonathan Lillie, John M. Drake 2016 National Institute of Mathematical and Biological Synthesis (NIMBioS)

Anticipating Elimination Of Mosquito-Borne Diseases, Suzanne M. O'Regan, Jonathan Lillie, John M. Drake

Biology and Medicine Through Mathematics Conference

No abstract provided.


The Influence Of Temperature Variation On Dengue Fever: A Model-Based Investigation, Michael A. Robert, Paula D. Weber, Rebecca C. Christofferson, Christopher N. Mores, Helen J. Wearing 2016 University of New Mexico

The Influence Of Temperature Variation On Dengue Fever: A Model-Based Investigation, Michael A. Robert, Paula D. Weber, Rebecca C. Christofferson, Christopher N. Mores, Helen J. Wearing

Biology and Medicine Through Mathematics Conference

No abstract provided.


Dynamics Of Two Pathogens In A Single Tick Population, Alexis White 2016 Old Dominion University

Dynamics Of Two Pathogens In A Single Tick Population, Alexis White

Biology and Medicine Through Mathematics Conference

No abstract provided.


Growth Dynamics For Pomacea Maculata, Lihong Zhao, Karyn L. Sutton, Jacoby Carter 2016 University of Louisiana at Lafayette

Growth Dynamics For Pomacea Maculata, Lihong Zhao, Karyn L. Sutton, Jacoby Carter

Biology and Medicine Through Mathematics Conference

No abstract provided.


Movement And Dynamics Of Norway Rats In An Urban Landscape, Rosalyn Rael, Caz Taylor 2016 Tulane University of Louisiana

Movement And Dynamics Of Norway Rats In An Urban Landscape, Rosalyn Rael, Caz Taylor

Biology and Medicine Through Mathematics Conference

No abstract provided.


Digital Commons powered by bepress