What Is Ecology? Introduction, Epistemology, & Ontology

Wildflowers in a meadow with a mountain and trees in the background
Source: National Park Service (Public Domain)

This lesson describes what ecology is and how ecologists produce knowledge. This lesson includes an overview of the scope of ecology, a discussion of the philosophical underpinnings of ecological inquiry, an exploration of these ideas using a classic ecological topic as a case study, and a discussion of the role of ecology in socio-environmental synthesis research. It is primarily intended for people interested in socio-environmental science who are not professional ecologists, such as undergraduate or graduate students in any field, or researchers or professionals with primary training outside ecological sciences—social scientists, scholars of humanities, fine artists, and biophysical scientists from other fields.  We present the lesson as an outline for use by a teacher or facilitator, but it may also be useful for individual learning.

Assumed Prior Knowledge
Designed for non-ecologists at the college level and above.
Learning Objectives
  • Expose participants to the breadth of research questions, methods, and motivations found within ecological research communities.
  • Illustrate ecological approaches to understanding problems and questions in socio-environmental systems, highlighting both common concerns and scale- or subfield-specific distinctions.
  • Facilitate collaboration with ecologists and further focused learning by establishing familiarity with foundational principles, terminology, and reasoning used by working ecologists and providing resources for further learning.
Key Terms/Concepts
ecology; epistemology; metaphysics; ontology
The “Hook” (suggestions for quickly engaging students)

Have participants examine the image at the top of this lesson and write down a response (< 5min) to:  What is “ecological” in this image? What concept, idea, pattern, phenomenon, etc. do you see here that seems like a properly ecological thought?
Discuss briefly, sharing several examples of student/participant responses. Have students describe why their examples are ecological and not part of some other knowledge domain. (Inspired by Box 2.1 in Reiners' and Lockwood’s 2010 book Philosophical Foundations for the Practices of Ecology)

Teaching Assignments

An outline is presented here with accompanying slides.

  1. Introduction: Why Ecology?

    Give a lecture or presentation or have a guided discussion on the kinds of questions and problems ecological science addresses and what defines the field as a community of intellectual practice.  This is a very basic lesson designed to:

    • Introduce the key knowledge domains and objects of study within ecology
    • Sketch likely borders of the discipline
    • Describe the key philosophical features of the practice of ecology with reference to its development as a distinct discipline.

    This lesson asks participants to consider: why is ecology not a sub-field of biology, or chemistry or physics, and what distinguishes it from environmental humanities, social sciences, or activism?

  2. Epistemology & Ontology: Case Study of Ecological Knowledge
    Snowshoe hare population dynamics and predator-prey interactions

    The purpose of this case study is to provide a concrete example of a firmly “ecological” pursuit of knowledge that participants will use to explore the intellectual priorities, philosophical foundations, and methods of ecology more broadly. In this case study, developing a thorough understanding of current research into cyclical population dynamics and other concepts are less important than understanding why this work is considered ecology and not some other discipline. The first slide in the PowerPoint introduces the key questions that are at the heart of this lesson:

    • How do ecologists produce knowledge?
    • What assumptions are made? 
    • What methods are used?
    • How do these influence the work of ecologists? 

    The following bullets provide a little guide for instructors to parts of the PowerPoint and lesson prompts.

    • Slides 2–8: Introduce the background knowledge and observations that spurred interest by ecologists in the snowshoe hare dynamics. Note that: fur sales records are assumed to be a reasonable proxy for abundance, which was enough evidence to formulate research questions about the occurrence and causes of cyclical population dynamics. Note (or draw from students) the ontological claims involved—that individuals, species, and populations are real or meaningful enough to be studied as coherent objects. Similarly, note (or draw from students) other epistemological and metaphysical features of this narrative—e.g., that there are patterns in the world such as population cycles that can be understood as abstractions which can explain and predict real events, that observations of one or a few populations are meaningful at other times and for other populations of the species. Challenge students to articulate why explaining population cycles is an interesting research goal. 

    • Slides 9–10: Describe observational studies that led to modeling and discuss the use of models in ecology.

    • Slides 11–12: Present experimental results and discuss different modes of inquiry in ecology—observation, experiment, modeling—as distinct but interdependent.

    • Slide 13: Discuss recent modeling efforts using long-term data that incorporate the previous insights.

    • Slides 14–16: Review the authors’ stated motivations for the studies and then use the next several slides with question prompts to encourage the participants to think more deeply about unstated assumptions, motivations, and how the work was done. Questions on slides are numerous but include for example:

      • How did the authors formulate their questions, what kinds of information were important to them, and how did they use that information to draw conclusions?
      • What motivated each study? 
      • Do the various studies share assumptions about which kinds of evidence are important? Are their motivations similar?
      • What relationships with other living and non-living entities or phenomena are explicitly or implicitly included in these studies, and what is excluded?
      • What makes these studies ecological and not characteristic of some other disciplinary domain? 
      • Why have the phenomena involved stimulated a century of research?
      • What did the scientists involved in this work hope to gain, and why did studies continue beyond work published in the late 1970s?
      • Can ecological questions be “answered”? 
    • Slide 17:  Bring the lesson to a conclusion by discussing the big picture of what this case study showed about ecological thought, assumptions, methods, etc. Focus on questions like this:

      • What makes this ecology and not some other disciplinary domain?
      • Why have the phenomena involved stimulated a century of research?
      • What did the scientists involved in this work hope to gain, and why did studies continue beyond work published in the late 1970s? Can ecological questions be “answered”?
    • Articles used for snowshoe hare example:

      Krebs, C.J. et al. 1995. Impact of food and predation on the snowshoe hare cycle. Science, 269 (5227): 1112–1115. https://doi.org/10.1126/science.269.5227.1112

      Elton, C. S. (1924). Periodic fluctuations in the numbers of animals: their causes and effects. Journal of Experimental Biology, 2(1), 119-163. https://doi.org/10.1242/jeb.2.1.119

      Keith, L. B., & Windberg, L. A. (1978). A demographic analysis of the snowshoe hare cycle. Wildlife Monographs, (58), 3-70.  https://www.jstor.org/stable/3830596

      Oli, M. K., Krebs, C. J., Kenney, A. J., Boonstra, R., Boutin, S., & Hines, J. E. (2020). Demography of snowshoe hare population cycles. Ecology, 101(3), e02969. https://doi.org/10.1002/ecy.2969.


  3. Ecology Is a Broad and Deep Field

    As a group or individual activity have students browse the latest issue of the journal Ecology and find three research articles studying different scales or ecological entities (e.g., individual organisms/species, populations, communities, ecosystems, landscapes, entire biosphere).  Based on abstracts alone, compare and contrast the ecological entities and phenomena involved and the kinds of information and reasoning the authors rely on. Compare and contrast the three article abstracts. Share results with full class/group until diversity of the discipline is evident.

Background Information for the Instructor
  1. Philosophical Foundations for the Practices of Ecology

    • This book incorporates key points from others in this list and may be the most useful starting point.

    • Reiners, W. A., & Lockwood, J. A. (2010). Philosophical Foundations for the Practices of Ecology. Cambridge University Press.

  2. The Philosophy of Ecology: From Science to Synthesis 

    • Edited by an ecologist and a philosopher, this book illustrates the range of philosophical approaches available to ecologists and provides a basis for understanding the thinking on which many of today's environmental ideas are founded.

    • Keller, D. R., & Golley, F. B. (Eds.). (2000). The Philosophy of Ecology: From Science to Synthesis. University of Georgia Press.

  3. Ecological Understanding: The Nature of Theory and the Theory of Nature

    •  A view from “inside” ecology where three working ecologists present a framework for understanding the role of theory in the production of knowledge.

    • Pickett, S. T., Kolasa, J., & Jones, C. G. (2010). Ecological Understanding: The Nature of Theory and the Theory of Nature. Elsevier.

  4. Ecological Paradigms Lost 

    • This edited volume in the Theoretical Ecology series addresses the historical development and evolution of theoretical ideas in the field of ecology. Not only does Ecological Paradigms Lost recount the history of the discipline by practitioners of the science of ecology, it includes commentary on these historical reflections by philosophers of science. 

    • Beisner, B., & Cuddington, K. (Eds.). (2005). Ecological Paradigms Lost. Academic Press.

  5. Roots of Ecology: Antiquity to Haeckel

    • This book traces the history of ideas and observations about ecology from Plato and Aristotle down to Ernst Haeckel, who named and defined ecology in 1866.

    • Egerton, F. N. (2012). Roots of  Ecology: Antiquity to Haeckel. University of California Press.

  6. A History of the Ecosystem Concept in Ecology: More Than the Sum of the Parts

    • In this book an eminent ecologist explains the ecosystem concept, tracing its evolution, describing how numerous American and European researchers contributed to its evolution, and discussing the explosive growth of ecosystem studies.

    • Golley, F. B. (1993). A History of the Ecosystem Concept in Ecology: More Than the Sum of the Parts. Yale University Press.

  7. The Evolution of American Ecology

    • These four books provide overviews and historical perspectives on the development of ecology as a discipline, the foundations of early ecological thought, and changes in the discipline over time (emphasizing USA). Kingsland (2005) is the most straightforward presentation of how the priorities of the discipline have developed in recent time.


    • Kingsland, S. E. (2005). The Evolution of American Ecology, 1890-2000. Johns Hopkins University Press.

  8. The Structural Links Between Ecology, Evolution, and Ethics: The Virtuous Epistemic Circle

    • This book addresses the foundational themes that interconnect evolutionary studies, ecology, and ethics. It sets out foundational events in the history of evolutionary biology, ecology, and environmental ethics.

    • Bergandi, D. (Ed.). (2013). The Structural Links Between Ecology, Evolution, and Ethics: The Virtuous Epistemic Circle. Springer Science & Business Media.

  9. A Non-Philosophical Theory of Nature: Ecologies of Thought 


    • These two philosophical works attempt to substantively engage with or integrate recent ecological science perspectives.

    •  Smith, A. (2013). A Non-Philosophical Theory of Nature: Ecologies of Thought. Springer.