BIOS 615 Ecology

Overview

Course Description:

“The structure and dynamics of plant and animal populations are considered with critical evaluations of current concepts. Emphases include the relative roles of competition and trophic interactions in population dynamics and how communities are structured. Applications of ecological concepts will consider aspects of conservation biology, pest control, agroecosystem function, and risks of genetic engineering.”

Prerequisite: A course in Ecology or consent of instructor.

Course Rationale: BIOS 615 – Ecology is a graduate core course for both the Master of Science in Biological Sciences and the Doctor of Philosophy in Biological Sciences.

INTRODUCTION

As you know this course in ecology is part of the graduate core curriculum in the Department of Biological Sciences and is designed to reflect the historical background to population ecology, the dominant theoretical themes, as well as recent developments in theory and application. The emphasis is on population ecology and its interface with community ecology.

Although we will touch on how populations influence community structure, the primary focus of the course will be on Population Ecology. Of course, ecology encompasses the study of how organisms interact with their "home" or "oikos", which as you know reflects their "niche", and we can study these interactions at any level of organization from individuals, through populations, communities and ecosystems, to landscapes and biomes. Arguably, for most ecologists the population level of organization, with its inherent variability, is the level that most of us study whether or not we want to understand the ecologies of any of the changing scales of organization from individuals to biomes. Thus population ecology has become central to much of ecological theory and practice and it is at the population level that ecologists have tried hardest to understand the processes that structure observed patterns of interaction.

Moreover, population ecology is becoming increasingly important in biomedical applications because it provides some valuable epidemiological, behavioral and dynamical tools for understanding molecular and cellular interactions as well as those between microparasitic diseases and their hosts (e.g. viral, bacterial, protozoan, fungal diseases etc.).

Pattern and process are the lifeblood of ecology and it is through our efforts to understand the processes that structure observed patterns of distribution and abundance of organisms that the science of ecology advances.

COURSE THEME

As long ago as 1798 the British political economist Thomas Robert Malthus realized that human populations were increasing exponentially through logarithmic or geometric progression in the absence of any apparent checks to growth. Forty years later in 1838, the Belgian mathematician Pierre-François Verhulst was the first to describe mathematically a sigmoid curve for population growth that was constrained to an asymptote. This curve he called the "logistique" as opposed to the "logarithmique" of Malthus. However, Malthus was also aware of the logistic relationship in his "principle of population" and so this curve is perhaps best described as the "Malthus-Verhulst logistic equation" (Berryman, 1992).

Although largely ignored for more than 80 years this logistic curve became a central theme throughout ecology, once the Americans, Pearl and Reed resurrected the logistic formula in 1920 (Kingsland, 1991). Raymond Pearl was a statistician and he also called this relationship the "logistic curve" which is described by the differential equation:

dN/dt = rN[(K-N)/K] .... the same as dN/dt = rN(1-N/K),

in which:

N = the number of individuals in the population,

t = time,

r = the intrinsic rate of natural increase, and

K = the upper limit of population growth (the "carrying capacity").

Figure 6.29 (Begon et al. 1996) Exponential and sigmoidal increase in density (N) with time (t) for continuously breeding populations.

The logistic relationship was used particularly extensively by fisheries biologists who developed population models to manage fish harvests and in some texts and papers the logistic is also called the Verhulst-Pearl equation to reflect its pedigree.

In addition to these single species uses, the logistic equation has also been used to describe interactions between two species. The Italian physicist Vito Volterra used the logistic in 1926 to model interspecific competition. He also modeled prey-predator interactions, but with a “mass-action” approach, and this work was mirrored at the same time in the USA by Alfred Lotka, a mathematician and demographer. Thus this two-species model of predation is now known as the Lotka-Volterra predation model and provides a starting point for most considerations of predation, and despite the fact that this is not a logistic model it is simple to add a self-limiting, logistic term to the model. Although Lotka did not work on competitive interactions to the same extent as Volterra (Kingsland, 1991), the logistic model of interspecific competition is also widely known as the Lotka-Volterra competition model.

Many well known researchers have built on this foundation and we will examine a variety of these contributions throughout our course. As the course develops you will be given reading lists that will direct you to the classical primary literature as well as to some very recent developments and applications of basic theory in population ecology. The course text will be Begon, Harper and Townsend (1996) which is also the text I use for the undergraduate course, BIOS 301: Ecology. In my opinion this is the best ecology text available and although it is somewhat advanced for an undergraduate course, it has sufficient depth to provide a great basis for a graduate course.

Course Texts

Begon, M., J.L. Harper & C.R. Townsend. 1996. Ecology: Individuals, Populations and Communities. Third Edition. Blackwell Science, Oxford, 1068 pp. (required)

Alstad, D. 2001. Basic Populus Models of Ecology. Prentice Hall, 144 pp. (optional)

Literature Cited

Begon, M., J.L. Harper & C.R. Townsend. 1996. Ecology: Individuals, Populations and Communities. Third Edition. Blackwell Science, Oxford, 1068 pp.

Begon, M., M. Mortimer, & D.J. Thompson. 1996. Population Ecology: A unified study of animals and plants. Third Edition. Blackwell Science: Oxford, 247 pp.

Berryman, A.A. 1992. The origins and evolution of predator-prey theory. Ecology 73(5): 1530-1535.

Kingsland, S.E. 1991. Defining ecology as a science. Pages 1-13, In, L.A. Real & J.H. Brown (editors), Foundations of Ecology: Classic Papers with Commentaries. The University of Chicago Press, Chicago, 905 pp.

Royama, T. 1992. Analytical Population Dynamics. Chapman & Hall, London, 371 pp.

COURSE ORGANIZATION

Classes meet from 2:00 to 3:15 p.m. on Tuesdays and Thursdays each week. All classes will meet in room 1106 Wood Hall – the ecology teaching laboratory. We will meet in the ecology laboratory so that we can explore ecological concepts in more depth with hands-on computer simulations of many of the models we will discuss. These considerations will not be strongly mathematical and we will try to keep the computer labs as helpful and comprehensible as possible. The computers (all PCs) will be used as an interesting and entertaining means of understanding mathematical descriptions of ecological interactions. The software we will use is called "Populus: Simulations of Population Biology" and was developed by Don Alstad at the University of Minnesota (Alstad, 2001). This software development was funded by the National Science Foundation and so the program is free for educational use. Thus "Populus" is available as "course-specific software" (Biology/Ecology) on the server and is accessible from any of the University computing labs. If anyone would like a copy for their own PC you are welcome to borrow or copy discs from which you can install the program or you can download the software from the University of Minnesota Ecology FTP server.

Each Tuesday class will be a lecture and each Thursday class will explore that week’s ideas in various ways through simulations, models, discussion and presentations. Each student will give a presentation based on an assigned paper. Thus each week will be divided approximately into thirds: lecture + presentation + computer simulation.

(1) Lecture: Steve Malcolm will summarize the relevant text chapter each week and supplement this with notes and additional literature. Each class participant should also read the assigned text chapter or any assigned papers as preparation for each class session.

(2) Presentation: Each participant will be assigned a paper to present that is relevant to the session topic. Everyone in class must read this paper and submit a summary (half a page to one page in length) of its most relevant points (include purpose, validity of methods, results and analyses, and value of the conclusions) by the start of the relevant class. The assigned paper presenter will spend 20 minutes describing the paper with the use of prepared overhead transparencies and photocopied notes given to each class member (it is suggested that you do this in much the same way as the lecture will be presented - slides or any other audiovisual aids are also appropriate - we have lab PCs, and an LCD projector and DVD/video player available if anyone wants to make a PowerPoint or other medium presentation). The presenter must explain the paper and comment on its conceptual and methodological value as well as its relevance to the overall session topic. This presentation must be designed to stimulate discussion among class participants and the presenter should try to encourage participation. Points (as specified below) will be awarded to both the presenter and all class participants for the weekly summaries. The relevant papers will be made available in the classroom (1106 Wood Hall)).

(3) Computer simulations: These will use the Populus program to explore the models and concepts most relevant to Population Ecology. We will also use the program's "interaction engine" to build our own models to examine ideas that are not covered by the text. The results of assigned computer exercises will be assessed as specified during the course. Questions asked on printed handouts during these sessions should be handed in for evaluation based on your work with Populus.

(4) Review Paper: The course also requires that each participant must submit a review paper entitled, "The logistic equation in ecology: history, uses and abuses" This paper should follow the style and content of papers in the journal Ecological Monographs and it should be double spaced, 12pt font (either Times/Times Roman or Helvetica/Arial) and at least 10 pages long, excluding the Literature Cited and any figures you may use (see Ecological Monographs 64(1): 110-112 (1994) for Instructions to Authors). This review paper must be handed in no later than Thursday, 7 April 2005. Of course you are very welcome to hand it in earlier and you are also welcome to discuss it with Steve Malcolm and submit a draft before final submission.

This paper will be marked critically as though you were submitting it for publication. As a recent editor of an international journal I will use the same criteria for judging your paper. It should be readable, grammatically correct (also use a spelling checker) and must be word-processed. The source of figures used must be fully acknowledged and plagiarism must be avoided absolutely (any evidence of plagiarism will result in a score of zero). You may make this review very general with an emphasis on history, or mathematics, or biological concepts; or you may focus on a single problem or phenomenon.

For example, if you have a biomedical interest you may wish to compare the use of the Michaelis-Menten-Holling equation for the description of enzyme kinetics with its use to describe the foraging behavior of predators, parasites or herbivores, and subsequent incorporation into the logistic relationship. Or you may wish to focus on the disease dynamics of HIV infections, or the dynamics of medfly populations in California, or how to describe whale populations, or the dynamics of harvested fish populations, or model moose-wolf interactions on Isle Royale, or lynx-grouse-hare interactions in Northern Canada, or assess the impact of Bt corn pollen on monarch butterfly populations in the field, or discuss whether populations actually show density-dependent, logistic limitation, etc. Citations and sources of information should focus on primary sources and must be cited as having been read (do not cite sources that you have not seen). Secondary and tertiary sources (e.g. web or magazine sources) may be used but must not predominate.

PERFORMANCE MEASUREMENT:

Performance in the course will be measured as indicated below:

Activity	points
(1) Paper presentation	100
(2) Paper summaries (at least 10 at 10 points each)	100
(3) Take-home mid-term exam (15 Feb., due 2:00 p.m. 24 Feb.)	100
(4) Computer session questions	100
(5) Review paper (due Thursday, 7 April 2005)	100
(6) Take-home final exam (12 Apr., due 4:45 p.m. 18 Apr.)	200
TOTAL	700

Grading scale:

A = >90%	BA = >85%
B = >80%	CB = >75%
C = >70%	DC = >65%
D = >60%	E = <60%

Students with Special Needs:

Students with disabilities or other special needs who need special accommodations in this course are invited to share these concerns or requests with the instructor as soon as possible.

Academic Honesty

You are responsible for making yourself aware of and understanding the policies and procedures in the Graduate Catalog that pertain to Academic Honesty (pp. 26-28). These policies include cheating, fabrication, falsification and forgery, multiple submission, plagiarism, complicity and computer misuse. If there is reason to believe you have been involved in academic dishonesty, you will be referred to the Office of Student Conduct. You will be given the opportunity to review the charge(s). If you believe you are not responsible, you will have the opportunity for a hearing. You should consult with me if you are uncertain about an issue of academic honesty prior to the submission of an assignment or test.