Population Ecology
Purpose of Course showclose
Ecology is the study of interactions between organisms and between organisms and their environments. Population ecology is the subfield of ecology that identifies those ecological factors—in the community or in the ecosystem—that regulate a population’s size.
Ecosystems and communities involve complex interactions that have evolved over long periods of time. The species that are present and the interactions we see between them are the result of evolution under the unique environmental pressures that exist in a given environment. These interactions may be delicately intertwined, such that the loss of a single species from a community could mean the collapse of the entire community in a domino effect. Thus, biologists are concerned with the preservation of biodiversity in ecosystems—retaining as many different species in the ecosystem as possible so the intricate relationships among species are preserved.
In recent years, we have seen a decrease in the biodiversity of ecosystems. Human activities are largely to blame for this decline: Commercial fishing and harvesting of species for souvenirs have dramatically reduced the populations of many aquatic species; oil spills have damaged the environment and threatened the survival of aquatic and terrestrial species; and human introduction of nonnative species (“invasive species”) has led to the extinction of native species. The alteration of environments from their original states to farmland, shopping centers, or housing developments has resulted in the loss of habitats suitable for the species that originally lived in those environments and accounts for much of this loss of biodiversity.
In this course, we will study interactions at the population level. In a broad sense, we are asking “How does a single-species group of individuals living in a given habitat (i.e., a population) manage to compete successfully with other species in order to obtain essential resources and yet not become so numerous that the population exceeds the habitat’s ability to support it?”
We will learn about intrinsic population growth (i.e., growth without limiting factors) and discover how such growth can be quantified. We will also discuss the factors that prevent a population from realizing its intrinsic growth potential and how those factors can be quantified. Finally, we will apply our understanding of population ecology to determine a population’s current status and construct a management plan to maintain that population at a desired size.
This course should prove particularly useful to those pursuing future study in epidemiology, behavior, wildlife management, evolution, or computational biology. It will provide a basis from which to understand complex ecological processes in a straightforward, quantifiable manner.
Course Information showclose
Course Designer: Kristian Demary, Ph.D
Primary Resources: This course is composed of a range of different free, online materials. However, the course makes primary use of the following materials:
- Stephen C. Stearns, Principles of Evolution, Ecology and Behavior (Yale University: Open Yale Courses), http://oyc.yale.edu (Accessed November 11, 2010). License: Creative Commons BY-NC-SA 3.0. The original version can be found here.
Learning Outcomes showclose
- Explain how population ecology is used to address problems in evolution, conservation, epidemiology, and resource management.
- Describe the interactions among and between the biotic and abiotic components of a healthy ecosystem and explain how these components are interdependent.
- Identify factors that threaten the maintenance of biodiversity in ecosystems and the population measures used to sustain ecosystem biodiversity.
- Use mathematical models and equations to describe population growth and interaction between populations.
- Identify density-dependent and density-independent factors that affect population growth and regulation.
- Employ the principles and techniques of population dynamics and ecology to analyze population viability and develop a resource management plan by using data gathered from a sample population.
Course Requirements showclose
√ Have a computer.
√ Have continuous broadband Internet access.
√ Have the ability/permission to install plug-ins or software (e.g., Adobe Reader or Flash).
√ Have the ability to download and save files and documents to a computer.
√ Have the ability to open Microsoft files and documents (.doc, .ppt., .xls, etc.).
√ Have competency in the English language.
√ Have completedhigh school biology and high school chemistry; high school algebra and high school calculus are recommended.
Additionally, it is recommended that you:
√ Have completed MA101: Single-Variable Calculus I.
√ Have read the Saylor Student Handbook.
√ Have completed the following courses listed in the Core Program for biology: BIO101: Introduction to Molecular and Cellular Biology, BIO101: Lab, BIO102: Introduction to Evolutionary Biology and Ecology, BIO102: Lab, and BIO105/CHEM101: General Chemistry I.
Unit Outline show close
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Unit 1: Population Ecology
In this unit, we will review basic terms and concepts important to understanding how a species or population fits into its environment. We will look at how an environment is organized, the typesof interactions that occur in an environment, the different strategies that organisms use to compete effectively within an environment, and why it is useful to know this information. Most of this material was touched on (at least briefly) in BIO102: Evolutionary and Ecological Biology. As a result, this unit should be something of a review. However, we will spend more time on various topics, such as life history evolution, that were not fully covered in previous biology courses.
Unit 1 Time Advisory show close
Unit 1 Learning Outcomes show close
- 1.1 What Is Population Ecology?
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1.1.1 The Definition of Population Ecology
- Reading: National Institute on Aging: Dr. Alexei Sharov: “What Is Population Ecology?”
Link: National Institute on Aging: Dr. Alexei Sharov: “What Is Population Ecology?” (HTML)
Instructions: Please read this entire webpage, which describes the field of population ecology.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: National Institute on Aging: Dr. Alexei Sharov: “What Is Population Ecology?”
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1.1.2 The Uses of Population Ecology
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Models as Analytical Tools”
Link: National Institute on Aging: Dr. Alexei Sharov: “Models as Analytical Tools” (HTML)
Instructions: Please read this entire webpage to learn how ecological models are used in population ecology to describe population dynamics.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Models as Analytical Tools”
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1.1.2.1 Understanding Evolution
- Lecture: Yale University: Dr. Stephen Stearns: “How Selection Changes the Genetic Composition of Population”
Link: Yale University: Dr. Stephen Stearns: “How Selection Changes the Genetic Composition of Population” (YouTube)
Also available in:
Adobe Flash and Quicktime
Instructions: Please click the Flash link under “Video” to watch this entire video (approximately 49 minutes). The transcript for this video is here (HTML). This lecture explains how the evolutionary process of natural selection molds the gene pool of a population.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Lecture: Yale University: Dr. Stephen Stearns: “How Selection Changes the Genetic Composition of Population”
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1.1.2.2 Epidemiology
- Reading: National Institutes of Health: Dr. Dieter Ebert: Ecology, Epidemiology, and Evolution of Parasitism in Daphnia: “Population Dynamics and Community Ecology”
Link: National Institutes of Health: Dr. Dieter Ebert: Ecology, Epidemiology, and Evolution of Parasitism inDaphnia: “Population Dynamics and Community Ecology” (HTML)
Instructions: Please read this entire webpage. This research illustrates the use of population ecology in the study of disease transmission.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: National Institutes of Health: Dr. Dieter Ebert: Ecology, Epidemiology, and Evolution of Parasitism in Daphnia: “Population Dynamics and Community Ecology”
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1.1.2.3 Resource Management
- Reading: University of Glasgow: Boyd Orr Centre for Population and Ecosystem Health: “Research Areas”
Link: University of Glasgow: Boyd Orr Centre for Population and Ecosystem Health: “Research Areas” (HTML)
Instructions: Please read this entire webpage to learn about current research in the field of population ecology. This material also covers subunit 1.1.2.4.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: University of Glasgow: Boyd Orr Centre for Population and Ecosystem Health: “Research Areas”
- 1.1.2.4 Conservation
- 1.2 Ecological Terms
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1.2.1 Habitats
- Lecture: Yale University: Dr. Stephen Stearns: “Interactions with the Physical Environment”
Link: Yale University: Dr. Stephen Stearns: “Interactions with the Physical Environment” (YouTube)
Also available in:
Adobe Flash, Quicktim
Instructions: Please click the Flash link under “Video” to watch this entire video (approximately 49 minutes). The transcript for this video is here (HTML). This lecture describes the abiotic factors that determine habitat. This material also covers subunit 1.3.1.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Lecture: Yale University: Dr. Stephen Stearns: “Interactions with the Physical Environment”
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1.2.2 The Niche
- Reading: Utah State University: Dr. Michelle Baker: “Competition”
Link: Utah State University: Dr. Michelle Baker: “Competition” (HTML)
Instructions: Please read this entire webpage. Pay special attention to the definition of “niche” and the difference between the fundamental niche and the realized niche. This material also covers subunits 3.4.1 and 3.4.1.3.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: Utah State University: Dr. Michelle Baker: “Competition”
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1.2.2.1 Fundamental Niche
- Reading: College of DuPage: Professor Lynn Fancher: “Niches”
Link: College of DuPage: Professor Lynn Fancher: “Niches”(HTML)
Instructions: Please read this entire webpage. Pay special attention to discussion of the fundamental niche. This material also covers subunit 1.2.2.2.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: College of DuPage: Professor Lynn Fancher: “Niches”
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1.2.2.2 Realized Niche
- Reading: PhysicalGeography.net: Introduction to the Biosphere: “Concept of Ecological Niche”
Link: PhysicalGeography.net: Introduction to the Biosphere: “Concept of Ecological Niche” (HTML)
Instructions: Please read this entire webpage. Pay special attention to the discussion of the realized niche.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: PhysicalGeography.net: Introduction to the Biosphere: “Concept of Ecological Niche”
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1.2.3 Limiting Resources
- Lecture: Yale University: Dr. Stephen Stearns: “Economic Decisions for the Foraging Individual”
Link: Yale University: Dr. Stephen Stearns: “Economic Decisions for the Foraging Individual” (YouTube)
Also available in:
Adobe Flash and Quicktime
Instructions: Please click the Flash link under “Video” to watch this entire video (approximately 50 minutes). The transcript for this video is here (HTML). This lecture discusses critical foraging decisions that must be made by individual organisms in order to obtain resources that might be available in limited supply and that are also being sought by conspecifics and individuals of other species.
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- Lecture: Yale University: Dr. Stephen Stearns: “Economic Decisions for the Foraging Individual”
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1.2.4 Keystone Species
- Reading: Marietta College: Ecology Pages: “Keystone Species”
Link: Marietta College: Ecology Pages: “Keystone Species” (HTML)
Instructions: Please read this entire webpage, which provides examples of how ecosystems can be destroyed entirely by the loss of a “keystone species.” Pay special attention to which characteristics might be used to determine whether a species is a keystone species.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: Marietta College: Ecology Pages: “Keystone Species”
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1.2.5 Foundation Species
- Reading: The Saylor Foundation's “Foundation Species and Dominant Species”
Link: The Saylor Foundation's “Foundation Species and Dominant Species” (PDF)
Instructions: Please read this entire PDF. Pay special attention to how the species identified as foundation species and dominant species alter the habitat in which they live, making the habitat more (or less) suitable for meeting other species’ needs. This material also covers subunit 1.2.6.See a broken link? Please let us know!
- Reading: The Saylor Foundation's “Foundation Species and Dominant Species”
- 1.2.6 Dominant Species
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1.2.7 Carrying Capacity
- Reading: The Sustainable Scale Project’s “Carrying Capacity”
Link: The Sustainable Scale Project’s “Carrying Capacity” (HTML)
Instructions: Please read this entire webpage, which provides a quick introduction to the concept of carrying capacity (K): the number of individuals of a species that can be supported by the habitat. This critical concept is used in population management decisions.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The Encyclopedia of Earth: Dr. Mark McGinley: “Carrying Capacity”
Link: The Encyclopedia of Earth: Dr. Mark McGinley: “Carrying Capacity” (HTML)
Instructions: Please read this entire webpage, which discusses the concept of carrying capacity and its application in population management in greater detail.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The Sustainable Scale Project’s “Carrying Capacity”
- 1.3 Ecological Organization
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1.3.1 Distribution of Organisms in Time and Space
- Lecture: Yale University: Dr. Stephen Stearns: “Climate and the Distribution of Life on Earth”
Links: Yale University: Dr. Stephen Stearns: “Climate and the Distribution of Life on Earth” (YouTube)
Also available in:
Adobe Flash, HTML, MP3 and Quicktime
Instructions: Please click the Flash link under “Video” to watch this entire video (approximately 43 minutes). The transcript for this video can be found here (HTML). The distribution of a population within a habitat (or multiple populations within a geographic area) directly affects the availability of resources and thus the optimal population size. This lecture discusses in particular how climate affects the distribution of organisms.
Terms of Use: Please respect the copyright and terms of use displayed on the webpages above.See a broken link? Please let us know!
- Lecture: Yale University: Dr. Stephen Stearns: “Climate and the Distribution of Life on Earth”
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1.3.2 Populations
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Population System”
Link: National Institute on Aging: Dr. Alexei Sharov: “Population System” (HTML)
Instructions: Please read this entire webpage, which discusses the factors that make up a population system. A population consists of all the members of a single species that are living together in the same habitat.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Population System”
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1.3.3 Communities
- Lecture: Yale University: Dr. Stephen Stearns: “Ecological Communities”
Link: Yale University: Dr. Stephen Stearns: “Ecological Communities” (YouTube)
Also available in:
Adobe Flash and Quicktime
Instructions: Please click the Flash link under “Video” to watch this entire video (approximately 46 minutes). The transcript for this video is here (HTML). This lecture describes how populations of interacting species make up a community of species all occupying the same area and interacting with each other.
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- Lecture: Yale University: Dr. Stephen Stearns: “Ecological Communities”
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1.3.4 Ecosystems
- Lecture: Yale University: Dr. Stephen Stearns: “Energy and Matter in Ecosystems”
Link: Yale University: Dr. Stephen Stearns: “Energy and Matter in Ecosystems” (YouTube)
Also available in:
Adobe Flash and Quicktime
Instructions: Please click the Flash link under “Video” to watch this entire video (approximately 50 minutes). The transcript for this video is here (HTML). This lecture discusses the two critical processes that occur in ecosystems: energy flow among trophic levels and the recycling of nutrients between organic (usable) forms and inorganic (nonusable) forms.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: Marietta College: Dr. Dave McShaffrey: “Environmental Science – Ecosystems”
Link: Marietta College: Dr. Dave McShaffrey: “Environmental Science – Ecosystems” (HTML)
Instructions: Please read this entire webpage. Pay special attention to the descriptions of biotic and abiotic components of ecosystems.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Lecture: Yale University: Dr. Stephen Stearns: “Energy and Matter in Ecosystems”
- 1.4 Interspecific Interactions within a Community
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1.4.1 Interspecific Competition
- Lecture: Yale University: Dr. Stephen Stearns: “Interspecific Competition”
Link: Yale University: Dr. Stephen Stearns: “Interspecific Competition” (YouTube)
Also available in:
Adobe Flash and Quicktime
Instructions: Please click the Flash link under “Video” to watch this entire video (approximately 40 minutes). The transcript for this video is here (HTML). Interspecific competition—or the struggle by more than one species to obtain the same essential but limited resources—is what Charles Darwin referred to as “the struggle for existence.”
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: Marietta College: Ecology Pages: “Competition”
Link: Marietta College: Ecology Pages “Competition” (HTML)
Instructions: Please read this entire webpage, which describes scientific studies of interspecific competition.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Lecture: Yale University: Dr. Stephen Stearns: “Interspecific Competition”
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1.4.2 Predation
- Interactive Lab: PBS: “How Does Evolution Work?”: “Flashy Fish”
Link: PBS: “How Does Evolution Work?”: “Flashy Fish” (Adobe Flash)
Instructions: This activity, based on the real research of a real scientist, allows you to observe the outcome of an evolutionary interaction between predators and their prey and how this interspecific interaction between species stabilizes the population sizes of predator and prey. Please read about Professor John Endler’s research on brightly colored guppies in South America and the risk of predation taken by brightly colored male guppies in order to attract females for mating. Then, run a simulation of predator-prey interaction: Set the initial number of bright male guppies and drab male guppies in the population and the predators present. Run the simulation for 10 generations. Explain the final ratio of bright male guppies to drab male guppies in terms of trade-offs between mating success and risk of predation. This activity also covers subunits 1.4.2.1 and 1.4.2.2.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Interactive Lab: PBS: “How Does Evolution Work?”: “Flashy Fish”
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1.4.2.1 Predator-Prey Cycle
- Reading: Marietta College: Ecology Pages: “Predation, Crypsis, and Mimicry”
Link: Marietta College: Ecology Pages: “Predation, Crypsis, and Mimicry” (HTML)
Instructions: Please read this entire webpage. These examples illustrate how prey have evolved defenses against predators.
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- Reading: Marietta College: Ecology Pages: “Predation, Crypsis, and Mimicry”
- 1.4.2.2 Stabilizing Effects in Nature
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1.4.3 Symbiosis
- Reading: Marietta College: Ecology Pages: “Symbiosis”
Link: Marietta College: Ecology Pages: “Symbiosis” (HTML)
Instructions: Please read this entire webpage, which illustrates and discusses the various interdependent relationships between species (symbioses) that have evolved in nature. This material also covers subunits 1.4.3.1 and 1.4.3.4.2.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: Marietta College: Ecology Pages: “Symbiosis”
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1.4.3.1 Ammensalism
- Reading: Tennessee State University: Professor Phil Ganter: “Interspecific Competition”
Link: Tennessee State University: Professor Phil Ganter: “Interspecific Competition” (HTML)
Instructions: Please read this entire webpage, which discusses other interspecific interactions. Pay special attention to the description of ammensalism. This material also covers subunits 1.4.3.2 through 1.4.3.4.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: Tennessee State University: Professor Phil Ganter: “Interspecific Competition”
- 1.4.3.2 Commensalism
- 1.4.3.3 Mutualism
- 1.4.3.4 Parasitism
- 1.4.3.4.1 True Parasitism
- 1.4.3.4.2 Parasitoidism
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1.5 Coevolution
- Lecture: Yale University: Dr. Stephen Stearns: “Coevolution”
Link: Yale University: Dr. Stephen Stearns: “Coevolution” (YouTube)
Also available in:
Adobe Flash and Quicktime
Instructions: Please click the Flash link under “Video” to watch this entire video (approximately 48 minutes). The transcript for this video is here (HTML). This lecture discusses coevolution— the evolutionary process in which the evolution of one species is influenced by interspecific interaction with another species. Mutualism can result from coevolved symbiotic relationships, where each species has evolved to benefit from its interaction with the other species. This material also covers subunit 1.5.2.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Lecture: Yale University: Dr. Stephen Stearns: “Coevolution”
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1.5.1 Example of Coevolved Parasite-Host Cycle
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Host-Parasitoid Model” and “Host-Pathogen Model (Anderson & May)”
Links: National Institute on Aging: Dr. Alexei Sharov: “Host-Parasitoid Models” (HTML) and “Host-Pathogen Model (Anderson & May)” (HTML)
Instructions: Please read these entire webpages. Parasite-host cycles are coevolved interspecific relationships that have become obligate for the parasite; it must complete its life cycle with specific hosts or die. This material also covers subunits 3.4.4 through 3.4.4.2.
Terms of Use: Please respect the copyright and terms of use displayed on the webpages above.See a broken link? Please let us know!
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Host-Parasitoid Model” and “Host-Pathogen Model (Anderson & May)”
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1.5.2 Example of Mutualistic Coevolution
- Reading: Brown University: Dr. David Brown: “Coevolution”
Link: Brown University: Dr. David Brown: “Coevolution” (HTML)
Instructions: Please read this entire webpage for a discussion of the strict, traditional definition of coevolution. This discussion reviews the classic studies of coevolution and cautions that not all mutualism relationships are coevolution; evidence from congruent evolutionary analyses is needed to support the idea of coevolution.
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- Reading: Brown University: Dr. David Brown: “Coevolution”
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1.6 Succession
- Reading: Utah State University: Dr. Michelle Baker: “Succession and Stability”
Link: Utah State University: Dr. Michelle Baker: “Succession and Stability” (HTML)
Instructions: Please read this entire webpage, which describes the evolutionary process of succession. During succession, the availability of resources changes over time and thus the carrying capacity for a given population changes as succession progresses. This material also covers subunits 1.6.1 through 1.6.3.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: Marietta College: Ecology Pages: “Succession Case Studies”
Link: Marietta College: Ecology Pages: “Succession Case Studies” (HTML)
Instructions: Please read this entire webpage, which provides outstanding photographs of succession in real habitats. This material also covers subunits 1.6.1 through 1.6.3.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: Utah State University: Dr. Michelle Baker: “Succession and Stability”
- 1.6.1 Primary Succession
- 1.6.2 Secondary Succession
- 1.6.3 Climax Community
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1.6.4 Cyclic Succession
- Reading: Wikipedia: “Cyclic Succession”
Link: Wikipedia: “Cyclic Succession” (PDF)
Instructions: Please read this entire webpage, which discusses the newer concept of cyclic succession, which challenges the traditional idea of succession resulting in a climax community.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: Wikipedia: “Cyclic Succession”
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1.7 Process of Adaptation
- Lecture: Yale University: Dr. Stephen Stearns: “Adaptive Evolution: Natural Selection”
Link: Yale University: Dr. Stephen Stearns: “Adaptive Evolution: Natural Selection” (YouTube)
Also available in:
Adobe Flash and Quicktime
Instructions: Please click the Flash link under “Video” to watch this entire video (approximately 46 minutes). The transcript for this video is here (HTML). This lecture discusses the central concept of modern biology: Charles Darwin’s theory of evolution by natural selection. This theory explains how populations survive by becoming adapted to the conditions in their environment.
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- Lecture: Yale University: Dr. Stephen Stearns: “Adaptive Evolution: Natural Selection”
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1.7.1 The Saylor Foundation: “Effects of Adaptation on Population Growth”
- Reading: The Saylor Foundation: “Effects of Adaptation on Population Growth”
Link: The Saylor Foundation: “Effects of Adaptation on Population Growth” (PDF)
Instructions: Please read this entire PDF, which explains how adaptation by a species affects its population growth.See a broken link? Please let us know!
- Reading: The Saylor Foundation: “Effects of Adaptation on Population Growth”
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1.8 Life History Evolution
- Lecture: Yale University: Dr. Stephen Stearns: “Life History Evolution”
Link: Yale University: Dr. Stephen Stearns: “Life History Evolution” (YouTube)
Also available in:
Adobe Flash and Quicktime
Instructions: Please click the Flash link under “Video” to watch this entire video (approximately 46 minutes) for a discussion of life history strategies. The transcript for this video is here (HTML). Life history strategies— the sequences of lifetime events that species evolve in order to cope with environmental pressures—directly affect the population birth and death rates for each species. Understanding the life history strategy a population has evolved (or the varied strategies evolved by all the species within a community) is essential for understanding population growth and cycles.
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- Lecture: Yale University: Dr. Stephen Stearns: “Life History Evolution”
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1.8.1 Reproductive Strategies
- Reading: The Saylor Foundation's "Reproductive Strategies"
Link: The Saylor Foundation's "Reproductive Strategies" (PDF)
Instructions: Please read this entire PDF. Darwin’s theory of natural selection asserts that survival is only half the battle; to be successful, survivors must reproduce and pass their success-producing genes to the next generation. Reproduction is essential for survival of the species; therefore, the reproductive strategy evolved by a population is a critical life history trait. Evolution has produced multiple successful reproductive strategies, which are discussed in this reading. This material also covers subunits 1.8.1.1 and 1.8.1.2.See a broken link? Please let us know!
- Reading: The Saylor Foundation's "Reproductive Strategies"
- 1.8.1.1 Alternation of Generations
- 1.8.1.2 Asexual Reproduction
- 1.8.1.3 Sexual Reproduction
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1.8.1.3.1 Marsupial vs. Placental Reproduction
- Lecture: Yale University: Dr. Stephen Stearns: “The Evolution of Sex” and “Sexual Selection”
Links: Yale University: Dr. Stephen Stearns: “The Evolution of Sex” (YouTube) and “Sexual Selection” (YouTube)
The Evolution of Sex also available in:
Adobe Flash and Quicktime
Sexual selection also available in:
Adobe Flash and Quicktime
Instructions: Please click the Flash link under “Video” to watch these entire videos (approximately 49 and 46 minutes, respectively). The transcripts for these videos are here (HTML) and here (HTML), respectively. Sexual reproduction confers genetic advantages that nonsexually reproducing organisms lack. These lectures explain this idea.
Terms of Use: Please respect the copyright and terms of use displayed on the webpages above.See a broken link? Please let us know!
- Lecture: Yale University: Dr. Stephen Stearns: “Evolutionary Game Theory: Fighting and Contests,” “Mating Systems and Parental Care,” “Alternative Breeding Strategies,” and “Selfishness and Altruism”
Links: Yale University: Dr. Stephen Stearns: “Evolutionary Game Theory: Fighting and Contests,” “Mating Systems and Parental Care,” “Alternative Breeding Strategies,” and “Selfishness and Altruism” (YouTube)
Note: All of the resources above are available in YouTube.
Evolutionary Game Theory also available in:
Adobe Flash and Quicktime
Mating Systems and Parental care also available in:
Adobe Flash and Quicktime
Alternative Breeding Strategies also available in:
Adobe Flash and Quicktime
Selfishness and Altruism also available in:
Adobe Flash and Quicktime
Instructions: Please click the Flash link under “Video” to watch these entire videos (approximately 45, 41, 44, and 31 minutes, respectively). The transcripts for these videos are here, here, here, and here (HTML), respectively. These lectures discuss theories proposed to explain observed reproductive behaviors that seem to conflict with evolutionary “fitness” theory, such as why males compete for mates, why some species show parental care and others do not, why only some individuals in a group breed, and why some individuals in some species will forego breeding themselves and help others raise their young.
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- Lecture: Yale University: Dr. Stephen Stearns: “The Evolution of Sex” and “Sexual Selection”
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1.8.1.4 r-Selected Species and K-Selected Species
- Reading: Utah State University: Dr. Michelle Baker: “Life Histories”
Link: Utah State University: Dr. Michelle Baker: “Life Histories” (HTML)
Instructions: Please read this entire webpage, which describes the life history trait of reproduction. Population growth is most affected by either the species’ physiological reproductive capacity (r-selected) or by the carrying capacity of the environment (K-selected). Pay special attention to the characteristics that distinguish r-selected species and K-selected species.
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- Reading: Utah State University: Dr. Michelle Baker: “Life Histories”
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Unit 2: Population Fundamentals: Describing and Quantifying Populations
In this unit, we will learn mathematical models to describe basic, single-species, density-independent population dynamics. We will look at how population growth is measured and then will examine the different ways population growth can be predicted. Birth rates, death rates, and age structuring of a population will be discussed and integrated into our predictive models. We will also discuss how a population reaches equilibrium and how population size might cycle across time, and we will identify two important measures of population size: minimum viable population and effective population size.
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Unit 2 Learning Outcomes show close
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2.1 Population Growth
- Reading: Utah State University: Dr. Michelle Baker: “Population Growth”
Link: Utah State University: Dr. Michelle Baker: “Population Growth” (HTML)
Instructions: Please read this entire webpage, which describes factors that are considered in mathematical models that determine population growth. All mathematical models provide only an estimate of population size. Even if members of the population are trapped and counted, one can never be certain that all individuals have been trapped and countedbecause some organisms are trap-shy. For every individual trapped and counted, scientists usually estimate that two additional individuals have not been counted. Therefore,estimates of population size are usually underestimates.This material also covers subunits 2.3 through 2.3.2.
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- Reading: Utah State University: Dr. Michelle Baker: “Population Growth”
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2.2 Growth Curves
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Exponential and Logistic Growth” and “Discrete-Time Analogs of the Exponential and Logistic Growth Models”
Links: National Institute on Aging: Dr. Alexei Sharov: “Exponential and Logistic Growth” (HTML) and “Discrete-Time Analogs of the Exponential and Logistic Models” (HTML)
Instructions: Please read these entire webpages, which describe the fundamental models of population growth.
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- Reading: National Institute on Aging: Dr. Alexei Sharov: “Exponential and Logistic Growth” and “Discrete-Time Analogs of the Exponential and Logistic Growth Models”
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2.2.1 Unlimited Growth: Exponential Growth
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Exponential Model”
Link: National Institute on Aging: Dr. Alexei Sharov: “Exponential Model” (HTML)
Instructions: Please read this entire webpage. The exponential growth model describes growth for a population with unlimited resources and no checks on reproduction or survival. From this basic model, all other population growth models are derived.
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- Reading: National Institute on Aging: Dr. Alexei Sharov: “Exponential Model”
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2.2.2 Limited Growth: Logistic Growth
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Logistic Model”
Link: National Institute on Aging: Dr. Alexei Sharov: “Logistic Model” (HTML)
Instructions: Please read this entire webpage. The logistic growth model is derived from the exponential growth model but with limitations on population growth added. This model depicts real population growth more accurately.
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- Reading: National Institute on Aging: Dr. Alexei Sharov: “Logistic Model”
- 2.3 Generational Patterns
- 2.3.1 Distinct Generations
- 2.3.2 Overlapping Generations
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2.3.3 Life Tables
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Life-Tables and K-Values,” “Age-Dependent Life-Tables,” and “Stage-Dependent Life-Table”
Links: National Institute on Aging: Dr. Alexei Sharov: “Life-Tables and K-Values,” (HTML) “Age-Dependent Life-Tables,” (HTML) and “Stage-Dependent Life-Tables” (HTML)
Instructions: Please read these entire webpages. Life tables describe populations in terms of age, sex, life stage, or cohort and are used for making decision about the population. For example, life tables for humans are used by life insurance companies to set premiums for their policies.
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- Reading: Utah State University: Dr. Michelle Baker: “Population Ecology 2”
Link: Utah State University: Dr. Michelle Baker: “Population Ecology 2” (HTML)
Instructions: Please read this entire webpage, which further compares the various life tables. This material also covers subunits 2.3.3.1 through 2.3.3.3.
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- Reading: National Institute on Aging: Dr. Alexei Sharov: “Life-Tables and K-Values,” “Age-Dependent Life-Tables,” and “Stage-Dependent Life-Table”
- 2.3.3.1 General Life Table
- 2.3.3.2 Cohort Life Table
- 2.3.3.3 Static Life Table
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2.4 Leslie Matrix
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Model of Leslie,” “Model Structure,” and “Model Behavior”
Links: National Institute on Aging: Dr. Alexei Sharov: “Model of Leslie,” (HTML) “Model Structure,” (HTML) and “Model Behavior” (HTML)
Instructions: Please read these entire webpages. This material also covers subunit 2.4.1. The Leslie matrix is used to study age-specific population growth. This matrix can help a scientist understand how population growth affects age structure in a population as well as how age structure in a population affects population growth.
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- Reading: National Institute on Aging: Dr. Alexei Sharov: “Model of Leslie,” “Model Structure,” and “Model Behavior”
- 2.4.1 The Leslie Matrix Setup
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2.4.2 Example of the Leslie Matrix
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Model of Leslie”
Link: National Institute on Aging: Dr. Alexei Sharov: “Model of Leslie” (HTML)
Instructions: Please read this entire webpage and then complete the questions.
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- Reading: National Institute on Aging: Dr. Alexei Sharov: “Model of Leslie”
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2.5 Equilibrium
- Reading: The Saylor Foundation: “Equilibrium”
Link: The Saylor Foundation: “Equilibrium” (PDF)
Instructions: Please read this entire PDF to understand how population growth arrives at an equilibrium size.See a broken link? Please let us know!
- Reading: The Saylor Foundation: “Equilibrium”
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2.6 Population Cycles
- Reading: The Saylor Foundation's “Population Cycles”
Link: The Saylor Foundation's “Population Cycles” (PDF)
Instructions: Please read this entire PDF. Real populations fluctuate in size regularly, as the population is affected by environmental factors or intrinsic life history factors. In some cases, these fluctuations are cycles that recur regularly at a specific time interval.
See a broken link? Please let us know!
- Reading: The Saylor Foundation's “Population Cycles”
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2.7 Minimum Viable Population
- Reading: University of Idaho College of Natural Resources: Amy Campbell and Bethany Eckroth: “Minimum Viable Population for the Bay Checkerspot Butterfly”
Link: University of Idaho College of Natural Resources: Amy Campbell and Bethany Eckroth: “Minimum Viable Population for the Bay Checkerspot Butterfly” (HTML)
Instructions: Please scroll down to the bottom of this webpage, click the “Checkerspot” link, and then read this entire PDF, which describes a field study on the Checkerspot butterfly aimed at determining the MVP for the population and designing a conservation program for the species.
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- Reading: The Encyclopedia of Earth: Dr. Lochlan W. Traill et al.: “Minimum Viable Population Size”
Link: The Encyclopedia of Earth: Dr. Lochran W. Traillet al.: “Minimum Viable Population Size” (HTML)
Instructions: Please read this entire webpage, which describes minimum viable population (MVP): the minimum number of individuals necessary for the population to survive. This critical value is used extensively in conservation decisions.
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- Reading: University of Michigan: Professor David Allan: “Minimum Viable Populations”
Link: University of Michigan: Professor David Allan: “Minimum Viable Populations” (HTML)
Instructions: Please read this entire webpage, which presents further discussion of the minimum viable population. This material also covers subunit 4.2.
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- Reading: University of Idaho College of Natural Resources: Amy Campbell and Bethany Eckroth: “Minimum Viable Population for the Bay Checkerspot Butterfly”
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2.8 Effective Population Size
- Reading: The Saylor Foundation: “Effective Population Size”
Link: The Saylor Foundation: “Effective Population Size” (PDF)
Instructions: Please read this entire PDF, which explains the difference between minimum viable population and effective population size and discusses the controversy over which measure is more useful in making conservation decisions.
See a broken link? Please let us know!
- Reading: The Saylor Foundation: “Effective Population Size”
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Unit 3: Population Regulation: Intrinsic Factors and Environmental Pressures That Affect Population Size
In this unit, we will develop an understanding of natural population regulation. In reality, no habitat can support truly unchecked population growth. There will always be some limiting factor, whether it be an intrinsic factor imposed by the population itself or an extrinsic factor imposed by the environment (an “environmental pressure”). In this unit, we will begin to look at the issues that complicate theoretical population dynamics. We will discuss how intrinsic density-dependent factors, such as food or disease, impose a population ceiling beyond which population growth cannot be sustained. We will also learn how migration between populations within a metapopulation can sustain smaller, more isolated populations. Every habitat contains more than one species, and we will see how interactions between species populations will impact growth, carrying capacity, and sustainability of each species. We will also learn how to quantify the impact of these interspecific interactions on a population’s growth.
Unit 3 Time Advisory show close
Unit 3 Learning Outcomes show close
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3.1 Intrinsic Factors: Density-Dependent Factors Affecting Population Regulation
- Lecture: Yale University: Dr. Stephen Stearns: “Population Growth: Density Effects”
Link: Yale University: Dr. Stephen Stearns: “Population Growth: Density Effects” (YouTube)
Also available in:
Adobe Flash and Quicktime
Instructions: Please click the Flash link under “Video” to watch this entire video (approximately 43 minutes). The transcript for this video is here (HTML). This lecture discusses density-dependent factors (i.e., factors whose effect on the population increases with population size) and how they affect population growth. This material also covers subunits 3.1.1 through 3.1.5.
Note: The community interactions we learned about in Unit 1 come into play here. If there were only one species, with unlimited resources, the population could grow infinitely. Instead, a natural community will have some constraints. As a population increases, competition will also increase. Other organisms may also take advantage of the robust population to fill some of their own resource requirements (for nourishment!); disease, parasite load, and the predator population are also likely to increase. In this section, we will discuss how each of these can affect mathematical population models.
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- Reading: Tennessee State University: Professor Phil Ganter: “Intraspecific Population Regulation”
Link: Tennessee State University: Professor Phil Ganter: “Intraspecific Population Regulation” (HTML)
Instructions: Please read this entire webpage, which discusses factors affecting population growth. Also, please explore related links on this webpage to learn more about population regulation.
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- Lecture: Yale University: Dr. Stephen Stearns: “Population Growth: Density Effects”
- 3.1.1 Resource Availability
- 3.1.2 Disease
- 3.1.3 Parasitism
- 3.1.4 Predation
- 3.1.5 Immigration and Emigration
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3.2 Intrinsic Factor: Metapopulation Dynamics
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Metapopulation Models”
Link: National Institute on Aging: Dr. Alexei Sharov: “Metapopulation Models” (HTML)
Instructions: Please read this entire webpage, which describes how the concept of a metapopulation can be incorporated into models of population growth.
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- Reading: National Institute on Aging: Dr. Alexei Sharov: “Metapopulation Models”
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3.2.1 Definition and Models
- Reading: Ramas Ecological and Environmental Software: “A Short Introduction to Metapopulation Models and GIS”
Link: Ramas Ecological and Environmental Software: “A Short Introduction to Metapopulation Models and GIS” (HTML)
Instructions: Please read this entire webpage, which introduces the concept of a metapopulation: multiple small populations separatedin spacebutconnected via occasional immigration between the populations, such as often occurs between nearby islands.
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the webpage above.See a broken link? Please let us know!
- Reading: Environmental Sciences Division of Oak Ridge National Laboratory and Pacific Northwest Laboratory: Strategic Environmental Research and Development Program: “Metapopulation Models”
Link: Environmental Sciences Division of Oak Ridge National Laboratory and Pacific Northwest Laboratory: Strategic Environmental Research and Development Program: “Metapopulation Models” (HTML)
Instructions: Please read this entire webpage to expand your knowledge of metapopulation models.
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- Lecture: YouTube: robertandkylie: “Bugger Off with Metapopulation Theory”
Link: YouTube: robertandkylie: “Bugger Off with Metapopulation Theory” (YouTube)
Instructions: Please watch this entire video (approximately 3 minutes). Pay special attention to how the small populations within a metapopulation sustain one another through immigration. This material also covers subunits 3.2.2 and 3.5.
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- Reading: Ramas Ecological and Environmental Software: “A Short Introduction to Metapopulation Models and GIS”
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3.2.2 Rescue Effect in Metapopulation Dynamics
Note: As you have learned, ametapopulation consists of multiple small populations separatedin spacebut occasionallyconnected via immigration. Immigrants mightsometimes movebetween two of these populations, thussustaining(“rescuing”) population size ina small population that might otherwise go extinct. Please review the YouTubevideo “Bugger Off withMetapopulation Theory” in subunit 3.2.1.
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3.2.2.1 Huffaker’s Experiments
- Reading: Wikipedia: “Metapopulation”
Link: Wikipedia: “Metapopulation” (PDF)
Instructions: Please read this entire webpage. Pay special attention to the sections describing Huffaker’s experiments on predator-prey interactions and Levins’s model of metapopulation dynamics. This material also covers subunit 3.2.3.
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- Reading: Wikipedia: “Metapopulation”
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3.2.2.2 Island Observations
- Lecture: Yale University: Dr. Stephen Stearns: “Island Biogeography and Invasive Species”
Link: Yale University: Dr. Stephen Stearns: “Island Biogeography and Invasive Species” (YouTube)
Also available in:
Adobe Flash and Quicktime
Instructions: Please click the Flash link under “Video” to watch this entire video (approximately 41 minutes). The transcript for this video is here (HTML). This lecture discusses metapopulation dynamics on islands and the introduction of nonnative species (also termed “exotic” and “invasive” species) and their effects on the population growth of native species. This material also covers subunit 3.5.
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- Lecture: Yale University: Dr. Stephen Stearns: “Island Biogeography and Invasive Species”
- 3.2.3 Levins’s Model of Metapopulation Dynamics
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3.3 Environmental Pressure: Carrying Capacity— The Ricker Model
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Stability Analysis of the Ricker’s Model”
Link: National Institute on Aging: Dr. Alexei Sharov: “Stability Analysis of the Ricker’s Model” (HTML)
Instructions: Please read this entire webpage and then complete the questions. The Ricker model predicts when a growing population will approach its carrying capacity and settle into an equilibrium size.
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See a broken link? Please let us know!
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Stability Analysis of the Ricker’s Model”
- 3.4 Environmental Pressures: Interspecific Interactions—Interactions Between Populations
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3.4.1 Interspecific Competition
- Reading: University of Michigan: Global Change Program: “Competition and Resource Scarcity”
Link: University of Michigan: Global Change Program: “Competition and Resource Scarcity” (HTML)
Instructions: Please read this entire webpage, which discusses the effects on population size of competition between species for limited resources.
Terms of Use: Please respect the copyright and terms of use displayed on
the webpage above.See a broken link? Please let us know!
- Reading: University of Michigan: Global Change Program: “Competition and Resource Scarcity”
- 3.4.1.1 The Competitive Exclusion Principle
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3.4.1.2 Competitive Release
- Reading: The Saylor Foundation: “Competitive Release”
Link: The Saylor Foundation: “Competitive Release” (PDF)
Instructions: Please read this entire PDF, which discusses the classic study of competitive release, which showed how the size of a population changes when a competitor suddenly disappears.See a broken link? Please let us know!
- Reading: The Saylor Foundation: “Competitive Release”
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3.4.1.3 Lotka-Volterra Interspecific Competition Model
The Lotka-Volterra interspecific competition model is used to predict changes in population sizes when interspecific competitive interactions exist.
- 3.4.2 Predator-Prey Interactions
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3.4.2.1 Lotka-Volterra Predator-Prey Model
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Introduction,” “Lotka-Volterra Model,” “Functional and Numerical Responses,” and “Predator-Prey Model with Functional Response ”
Links: National Institute on Aging: Dr. Alexei Sharov: “Introduction,” “Lotka-Volterra Model,” “Functional and Numerical Response” and “Predator-Prey Model with Functional and Numerical Responses” (HTML)
Instructions: Please read these entire webpages. The Lotka-Volterra predator-prey model is used to predict predator-prey population size cycles based on the current size of each population. These materials also cover subunits 3.4.2.1.1 and 3.4.2.1.2.
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- Reading: National Institute on Aging: Dr. Alexei Sharov: “Introduction,” “Lotka-Volterra Model,” “Functional and Numerical Responses,” and “Predator-Prey Model with Functional Response ”
- 3.4.2.1.1 Functional Responses
- 3.4.2.1.2 Numerical Responses
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3.4.3 Mutualism
- Reading: Utah State University: Dr. Michelle Baker: “Mutualism”
Link: Utah State University: Dr. Michelle Baker: “Mutualism” (HTML)
Instructions: Please read this entire webpage, which discusses how mutualism relationships affect population size.
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- Reading: Utah State University: Dr. Michelle Baker: “Mutualism”
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3.4.3.1 Facultative Mutualism vs. Obligate Mutualism
- Reading: University of Michigan: Global Change Program: “Ecological Communities: Networks of Interacting Species”
Link: University of Michigan: Global Change Program: “Ecological Communities:Networks of Interacting Species” (HTML)
Instructions: Please read this entire webpage. Pay particular attention to the difference between facultative (optional) mutualism relationships and obligate (required) mutualism relationships.
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- Reading: University of Michigan: Global Change Program: “Ecological Communities: Networks of Interacting Species”
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3.4.3.1.1 Simple Model of Mutualism
- Reading: Tennessee State University: Professor Phil Ganter: “Modeling Mutualism”
Link: Tennessee State University: Professor Phil Ganter: “Modeling Mutualism” (HTML)
Instructions: Please read this entire section. Models of mutualism attempt to predict the effect of the mutualism relationship on the population sizes of the species involved in the relationship, but these models have not been useful when employed in real situations in the past.
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- Reading: Tennessee State University: Professor Phil Ganter: “Modeling Mutualism”
- 3.4.4 Host-Parasite Interactions
- 3.4.4.1 Parasite-Vector Model
- 3.4.4.2 Host-Parasitoid Model
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3.5 Environmental Pressure: Invasive Species—Introduced Environmental Pressure
- Reading: United States Department of Agriculture: National Invasive Species Information Center: “What Is an Evasive Species?” and Global Environmental Governance Project: "Invasive Species"
Links: United States Department of Agriculture: National Invasive Species Information Center:“What Is an Invasive Species?” and Global Environmental Governance Project: "Invasive Species"
Instructions: Please read these entire webpages. Also, please explore other links on both websites to learn more about the global problems caused by species being accidentally or intentionally released into habitats in which they did not evolve. These related links also cover subunit 4.4.
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- Reading: United States Department of Agriculture: National Invasive Species Information Center: “What Is an Evasive Species?” and Global Environmental Governance Project: "Invasive Species"
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3.5.1 Characteristics of Invasive Species
- Lecture: YouTube: Rob Piggott and Andrew Boncher: “Invasive Species Introduction” and Vimeo: World Wildlife Foundation: “Invasive Species – Introduction to the Issue”
Link: YouTube: Rob Piggott and Andrew Boncher: “Invasive Species Introduction” (YouTube) and Vimeo: World Wildlife Foundation: “Invasive Species – Introduction to the Issue” (Adobe Flash)
Instructions: Please watch these entire videos (approximately 8 minutes and 2 minutes, respectively). Pay particular attention to the characteristics that make some introduced species more likely to be successful in new habitats.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Lecture: YouTube: Rob Piggott and Andrew Boncher: “Invasive Species Introduction” and Vimeo: World Wildlife Foundation: “Invasive Species – Introduction to the Issue”
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3.5.2 Establishment of an Invasive Species in a New Habitat
- Reading: The Saylor Foundation: “Establishment of an Invasive Species in a New Habitat ”
Link: The Saylor Foundation: “Establishment of an Invasive Species in a New Habitat” (PDF)
Instructions: Please read this entire PDF, which discusses how the initial population size of an introduced species might be small initially but can rapidly reach problematic size. This material also covers subunits 3.5.2.1 through 3.5.2.3.See a broken link? Please let us know!
- Reading: The Saylor Foundation: “Establishment of an Invasive Species in a New Habitat ”
- 3.5.2.1 Propagule Pressure
- 3.5.2.2 Lag Period
- 3.5.2.3 Exponential Growth
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3.6 Environmental Pressures: Human Activities that Affect Population Size
- Reading: The Saylor Foundation's “Environmental Pressures: Human Activities That Affect Population Size”
Link: The Saylor Foundation's “Environmental Pressures: Human Activities That Affect Population Size” (PDF)
Instructions: Please read this entire PDF about human activities that dramatically impact and even threaten the survival of wild populations, taking notes where appropriate.See a broken link? Please let us know!
- Reading: The Saylor Foundation's “Environmental Pressures: Human Activities That Affect Population Size”
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Unit 4: Population Management: Artificial Regulation of Population Size
We will wrap up this course by learning how to apply our newfound knowledge of population dynamics to real-world situations. First, we will review the importance of conservation at the population, species, and ecosystem levels. Next, we will discuss the sampling methods used to gather the necessary data to develop population estimates and models. We will learn how to use this data to analyze the viability of a population. We will discuss methods of artificial population regulation. Finally, we will produce a resource management action plan.
Unit 4 Time Advisory show close
Unit 4 Learning Outcomes show close
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4.1 Importance of Conservation
- Reading: The Saylor Foundation's “Importance of Conservation”
Link: The Saylor Foundation's “Importance of Conservation” (PDF)
Instructions: Please read this entire PDF, which discusses why conservation of wild populations is important and how everything you have learned so far in this course is used by professional biologists to accomplish the goals of population, habitat, and species conservation.See a broken link? Please let us know!
- Reading: The Saylor Foundation's “Importance of Conservation”
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4.2 Sampling Methods
- Reading: National Institute on Aging: Dr. Alexei Sharov: “Estimation of Population Density and Size”
Link: National Institute on Aging: Dr. Alexei Sharov: “Estimation of Population Density and Size” (HTML)
Instructions: Please click all eight links to read these entire sections, which explain various sampling methods used to estimate population sizes in the field. These materials also cover subunits 4.2.1, 4.2.2, and 4.2.4.
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- Reading: National Institute on Aging: Dr. Alexei Sharov: “Estimation of Population Density and Size”
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4.2.1 Basic Count
- Lecture: YouTube: JeliBaggins4444: “How to Process a Gunnison’s Prairie Dog” and sumira821: “Processing”
Links:YouTube: JeliBaggins4444: “How to Process a Gunnison’s Prairie Dog” (YouTube) and sumira821: “Processing” (YouTube)
Instructions: Please watch these entire videos (approximately 8 minutes and 11 minutes, respectively), which show student field assistant interns collecting data on Gunnison’s prairie dogs in New Mexico.
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- Lecture: YouTube: JeliBaggins4444: “How to Process a Gunnison’s Prairie Dog” and sumira821: “Processing”
- 4.2.2 Random Plot Sampling
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4.2.3 Transect Lines
- Reading: The Saylor Foundation: “Transect Lines”
Link: The Saylor Foundation: “Transect Lines” (PDF)
Instructions: Please read this entire PDF, which explains the technique of estimating population size by using transect lines.See a broken link? Please let us know!
- Reading: The Saylor Foundation: “Transect Lines”
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4.2.4 Mark and Recapture
- Lecture: iTunes U: Agnes Scott College: Dr. Lock Rogers, Bess Harris, and April Garrett: “Frog Sampling for Mark/Recapture”
Link: iTunes U: Agnes Scott College: Dr. Lock Rogers, Bess Harris, and April Garrett: “Frog Sampling for Mark/Recapture” (iTunes)
Instructions: Please click this link, which might ask you to launch iTunes, and then listen to this entire lecture (approximately 10 minutes), which describes the mark/recapture technique for estimating population size.
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- Lecture: iTunes U: Agnes Scott College: Dr. Lock Rogers, Bess Harris, and April Garrett: “Frog Sampling for Mark/Recapture”
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4.3 Population Viability Analysis
- Reading: Ramas: Ecological and Environmental Software: “A Short Introduction to Population Viability Analysis”
Link: Ramas: Ecological and Environmental Software: “A Short Introduction to Population Viability Analysis” (HTML)
Instructions: Please read this entire webpage. A population viability analysis (PVA) is conducted to assess the current size of a population, assess whether that size is large enough to ensure survival of the population, and design conservation programs to preserve the population by using the information obtained.
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- Reading: University of Connecticut: Dr. Kent Holsinger: “Population Viability Analysis”
Link: University of Connecticut: Dr. Kent Holsinger: “Population Viability Analysis”(HTML)
Instructions: Please read this entire webpage, which highlights certain aspects of a PVA deemed particularly important by this researcher.
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- Reading: Colorado State University: Dr. Gary White: “Population Viability Analysis”
Link: Colorado State University: Dr. Gary White: “Population Viability Analysis”(HTML)
Instructions: Please read this entire presentation, ensuring to use the buttons at the bottom of the page to navigate through the pages.
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- Reading: The Nature Conservancy: William Morris et al.: “A Practical Handbook for Population Viability Analysis”
Link: The Nature Conservancy: William Morris et al.: “A Practical Handbook for Population Viability Analysis” (PDF)
Instructions: Please read this entire PDF. The discussion in this handbook will be useful to you at the end of this course, when you develop your own population viability analysis.
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- Reading: Ramas: Ecological and Environmental Software: “A Short Introduction to Population Viability Analysis”
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4.3.1 Applications of Population Viability Analyses
- Reading: The Saylor Foundation: “Applications of Population Viability Analyses”
Link: The Saylor Foundation: “Applications of Population Viability Analyses” (PDF)
Instructions: Please read this entire PDF, which discusses how population viability analyses are used. This material also covers subunits 4.3.1.1 through 4.3.1.4.See a broken link? Please let us know!
- Reading: The Saylor Foundation: “Applications of Population Viability Analyses”
- 4.3.1.1 Conservation of Populations
- 4.3.1.2 Conservation of Species
- 4.3.1.3 Conservation of Habitats
- 4.3.1.4 Epidemiology
- 4.3.1.4.1 Disease Transmission within the Population
- 4.3.1.4.2 Disease Transmission between Populations
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4.4 Methods of Artificial Population Regulation (Population Management)
- Reading: The Saylor Foundation: “Methods of Artificial Population Regulation (Population Management)”
Link: The Saylor Foundation: “Methods of Artificial Population Regulation (Population Management)” (PDF)
Instructions: Please read this entire PDF, which discusses the various methods used in artificial population regulation (population management). This material also covers subunits 4.4.1 through 4.4.5.See a broken link? Please let us know!
- Reading: The Saylor Foundation: “Methods of Artificial Population Regulation (Population Management)”
- 4.4.1 Eradication of the Population from an Area
- 4.4.2 Exclusion of the Population from an Area
- 4.4.3 Biological Control of the Population
- 4.4.4 Chemical Control of the Population
- 4.4.5 Integrated Regulation
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4.5 Resource Management Action Plan
- Reading: The Saylor Foundation: “Resource Management Action Plan”
Link: The Saylor Foundation: “Resource Management Action Plan” (PDF)
Instructions: Please read this entire PDF for instructions on applying your knowledge to develop a population viability analysis and a resource management action plan to preserve a population.
Terms of Use: Please respect the copyright and terms of use displayed on the webpage above.See a broken link? Please let us know!
- Reading: The Saylor Foundation: “Resource Management Action Plan”
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Final Exam
- Final Exam: The Saylor Foundation's BIO313 Final Exam
Link: The Saylor Foundation's BIO313 Final Exam
Instructions: You must be logged into your Saylor Foundation School account in order to access this exam. If you do not yet have an account, you will be able to create one, free of charge, after clicking the link.See a broken link? Please let us know!
- Final Exam: The Saylor Foundation's BIO313 Final Exam
Questions? Consult the FAQs!

