Derek Johnson Population Ecology Lab
Classes taught at VCU
Invasion Biology (BIOL 430)
Course Description: 3 lecture hours. 3 credits. Prerequisites: Minimum grades of “C” in BIOL 151, 152 and BIOZ 151, 152; BIOL 317. A comprehensive view on the ecology and impacts of invasive species.
Course Summary: As human travel and trade has reached the global scale over the last couple of centuries, we carry more and more intended and unintended organisms with us across geographic barriers. Since 1850, the average number of non-native species introductions per year has increased exponentially from just a few to well over 100 per year. A fraction of these non-native species increase to high densities, spread across the landscape, and become invasive species. Invasive species can displace native species, change biotic communities and affect ecosystem processes. When an invasive species is a plant we usually call it a weed, and when it is an animal we often call it a pest. In this class, we will look at the history and patterns of species invasions, why they occur, and their impacts on natural environments and native species communities. The course will focus on empirical examples and conflicting opinions to confront current invasion biology theory. The course will address such practical and philosophical topics as 1) Are non-native species inherently undesirable? 2) Why do some species invade while others do not? 3) How do we determine the optimal management practices to control non-native species? 4) What are the challenges non-native species face, as well as the advantages they benefit from over native species? The course will include lectures, class discussions, and written critiques of articles from the scientific literature. The goal of this class is to provide a comprehensive look at the field of invasion biology in the context of ecological concepts.
Kudzu is a non-native vine that is spreading at a rate of 150,000 acres annually in the southern United States. The shoots can grow at a rate of up to 1 ft per day, and can envelop bushes, trees, cars, and even buildings as they spread.
Population Ecology (BIOL 520)
Course Description: 3 lecture hours. 3 credits. Students are expected to have completed a general ecology course with a grade of "C" or better.
Course Summary:The objective of the course is to provide a broad basis for understanding the theoretical, empirical, and applied aspects of population ecology. The course begin with a review of the nuts and bolts of intraspecific population dynamics (e.g. exponential growth and logistic growth, and Allee effects) and the intrinsic and extrinsic effects on dynamics. Then we will expand to looking at ecological interactions including competition, predator-prey, host-parasite, host-parasitoid, host-pathogen, mutualisms, and tri-trophic interactions.
Density-independent (blue) and density dependent (red) growth create exponential and logistic growth curves, respectively.
Population Modelling (BIOL 591)
Course Description: 1 lecture hour and 3 lab hours. 2 credits. Students must have a solid foundation in population ecology to enroll in this course. Permission from the instructor is required for enrollment in this course.
Course Summary: This course provides a framework for graduate students to gain hands on experience in population modeling. Students are expected to identify an ecological question, build a population model to address the question, and write a publication-quality scientific paper as a final product to be turned in at the end of the semester. The course is structured to provide students an environment to work independently and in groups. The first portion of the course involves identification of a novel research question through literature mining. Students learn simulation modeling and model-fitting techniques in the R programming language. The instructor provides an introduction to using R at the beginning of the semester, but self-motivated and interactive group learning is necessary to gain adequate programming skills. As the semester progresses, students work more independently on their research projects.
Simulated time series of population density with sample points. Difference between points and line represent measurement error.
Outbreaks & Epidemics (BIOL 475)
Course Description: Capstone Semester course; 1 lecture hours. 1 credits. A course to explore the causes, impacts, and perceptions of species outbreaks and disease epidemics. Prerequisites: Completion of the Biocore with a minimum grades of C and 90 hours of undergraduate coursework.
Course Summary: The goal of this course is to look in depth into current outbreaks of pest species and/or infectious disease epidemics. For example, in the Fall 2014 the class focused on the ebola virus and learned about the West African epidemic as in unfolded. We read the current literature, followed World Health Organization, Centers for Disease Control, and media reports. We looked at the role of disease modeling, social knowledge
World Health Organization map of West African Ebola epidemic in the Fall 2014.
Infectious Disease Ecology (BIOL 459)
Course Description: 3 lecture hours. 3 credits. Students are expected to have completed VCU Biology core curriculum. A comprehensive view of infectious disease ecology from transmission to pathogen evolution to emerging diseases.
Course Summary: The goal of this course is to provide students with a solid background in the cutting edge research in infectious disease ecology. The course starts with a section on transmission theory and introduces the students to SIR-type modeling approaches to understanding epidemic and endemic spread. The second section focuses on evolution in pathogens. The third section brings the course together to understand the complexities in dynamics that develop when ecology and evolution meet on similar time scales in infectious disease systems.
Ecology (BIOL 317)
Course Description: 3 lecture hours. 3 credits. Prerequisites: BIOL and BIOZ 151 and BIOL and BIOZ 152, each with a minimum grade of C; and BIOL 200, MATH 200, MATH 201,STAT 210, STAT 212, STAT 314 or satisfactory score on the VCU Mathematics Placement Test within the one-year period immediately preceding the beginning of the course. Biology majors must have completed BIOL 200. An exploration of the theoretical and empirical foundations of evolutionary biology with a focus on the processes driving evolutionary change across all of life.
Course Summary: This is core Biology course with the goal of providing the students with a comprehensive background in the field of ecology from the individual to popuation to community to ecosystem processes. The students explore ecological concepts from a theoretical perspective, and how the field of ecology informs real world problems such as overharvest of plants and animals, pollution of terrestical and aquatic systems, and anthropogenic changes across the globe.
Epidemic spread in a spatially-explicit population. Spread is more likely between neighbors and in high density populations.
Graphic illustration of a two-strata model for detecting source-sink population dynamics.