UNM Biology Undergraduate Labs

Effects of Pollution on Community Structure


Food webs are an important component of community structure. Food webs are diagrams showing the pathway of energy through a community.

  • The Sun
    • Primary Producers
      • Primary consumers
        • Secondary consumers
          • Tertiary consumers...
            • Decomposers


Pollution affects the community structures seen in pond water. Pollutants can have many effects that might either increase or decrease the number of species, depending on the type of pollution. We used four different treatments meant to mimic what might be seen in the world today.

Removal of some organisms in the food web affects the whole web. If a predator or competitor is removed, then a species can increase in numbers.

Review Questions

- Define community.  Provide 2 real-life examples of a community.
- Is there a difference between an ecosystem and a community?  If so, what is the difference?
- Name the four kinds of pollution we studied in lab and give one cause for each.
- What are independent and dependent variables?
- What is the difference between a community and a population?
- Why should we be concerned if a particular pollutant reduces the numbers of aquatic microorganisms?
- What is an experimental control?
- Why is it important to use a control when implementing an experiment?
- The ______________ variable is the variable whose value changes in response to changes in another variable.
- Why is it important to obtain replicate samples when taking measurements within an experimental design?
- Match the pollution type with a preventative measure/treatment.  The system in question is a stream.

1.  Thermal A.  Prevent run-off from farms
2.  Organic pollution B.  Preserve riparian buffer zones that provide shading to stream
3.  Pesticides C.  Water treatment at a sewage point
4.  Acid Rain D.  Control industrial pollution

- What was the control sample that we looked at during our pollution lab?
- Label the axis of a graph illustrating the relationship between animal size and average environmental temperature.  Which is the dependent and independent variables.
- Define Adaptation.
- Give examples of morphological, behavioral, and physiological adaptations.