Population Ecology (saylor.org)

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.

Upon successful completion of this course, students will be able to:

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.