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BIO313: Population Ecology

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
This unit should take you approximately 26.5 hours to complete.

☐    Subunit 1.1: 3 hours

☐    Subunit 1.2: 5 hours

☐    Subunit 1.3: 5 hours

☐    Subunit 1.4: 3 hours

☐    Subunit 1.5: 2.5 hours

☐    Subunit 1.6: 1.0 hours

☐    Subunit 1.7: 2.5 hours

☐    Subunit 1.8: 4.5 hours

Unit1 Learning Outcomes
Upon successful completion of this unit, students will be able to: - Explain how population ecology addresses problems in evolution, conservation, epidemiology, and resource management. - Define ecological terms relevant to species interactions, community structure, population dynamics, and ecosystem functions. - Describe a population system and explain factors affecting processes within the population system. - Describe an ecological community and the relationships among the species that compose the community. - Describe the interactions among the biotic and abiotic components of an ecosystem and explain how these components are interdependent. - Describe and explain examples of coevolution. - Describe the process of adaptation and how adaptations—advantageous and disadvantageous—affect population growth. - Describe ecological succession and explain the role of ecological succession in habitat modification. - Explain the benefits of trade-offs in life history traits of r-selected and K-selected species. - Describe the evolutionary benefits of various modes of reproduction.

1.1 What Is Population Ecology?   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.

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.

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.
 
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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.
 
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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.
 
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1.1.2.4 Conservation   1.2 Ecological Terms   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.
 
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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.

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.
 
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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.
 
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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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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.
 
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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.

1.2.6 Dominant Species   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.
 
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  • 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.

1.3 Ecological Organization   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.
 
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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.

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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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.
 
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  • 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.
     
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1.4 Interspecific Interactions within a Community   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.”
 
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  • 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.

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.
 
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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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1.4.2.2 Stabilizing Effects in Nature   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.
 
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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.
 
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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   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.
 
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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.
 
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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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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.
 
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  • 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.
     
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1.6.1 Primary Succession   1.6.2 Secondary Succession   1.6.3 Climax Community   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.
 
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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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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.

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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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.

1.8.1.1 Alternation of Generations   1.8.1.2 Asexual Reproduction   1.8.1.3 Sexual Reproduction   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.
 
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  • 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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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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