ECOLOGY: The Study of Ecosystems

Ecology (from the Greek oikos meaning "house" or "dwelling", and logos meaning "discourse") is the study of the interactions of organisms with each other and their environment.

The hierarchy. We should be able to define each of the following.

Always remember that Ecology is a SCIENCE, not a sociopolitical movement (e.g., environmentalism).

The Ecologist engages in the hypothetico-deductive method to pose questions and devise testable hypotheses about ecosystems.

An ecosystem consists of

Evolution by natural selection is driven by ecological interactions.

Levels of Ecological Study


The plant community of a particular region depends on the CLIMATE--the combination of temperature, water, light, and wind. And the flora (plants) directly affects the composition of the fauna (animals).

The Components of Climate: How they Affect Living Things

  • WATER:


  • WIND:



  • The ability of an organism's to survive the extremes of its environment determine its survival and reproduction.
  • This is the basis of natural selection
  • The success of individuals in an ecosystem determines the structure of the population in that ecosystem.

    Animals can be categorized by their ability (or inability) to control their internal environment (salt balance, water balance, temperature, etc.):

    We can also categorize animals based on (1) where they get their heat and (2) how they regulate their body temperature:

    There is a continuum of tolerances to various environmental challenges within and among species. Beyond certain levels of any given factor, a lethal range exists. (Consider this for our own species!)

    Short-term responses to environmental changes are known as ADAPTATIONS. These are governed by the internal control (homeostatic) mechanisms in the individual, but the limits are set by the EVOLUTIONARY HISTORY of that individual.

    Individual adaptations to change may include:

  • physiological acclimation
  • morphological change
  • behavioral adaptation.


    You've all probably seen something like this:

    ...and know what a "food web" is.

    The food web is made up of organisms at different levels of feeding, known as TROPHIC LEVELS:

  • DECOMPOSERS are a special type of consumer that can eat dead, organic matter (detritus, carrion) and convert it back into its inorganic components.

    We also can categorize animals on the basis of the exact type of food they eat. You all have heard of...

    But don't forget...

    Insert your own favorite "vore" here!

    The Food Web reflects the flow of ENERGY and NUTRIENTS through ecosystems, which we'll cover in more detail later. But for now, we're going to create our own Food Web in a Florida Ecosystem.