Observing Ecological Succession

Observing Ecological Succession
This lesson allows students to witness how ecological communities respond to environmental
changes. Succession is often taught with forest growth as the primary example, but in this
outdoor experiment, students will be observing communities of insects over time.
HYPOTHESIS:
Ecological progression is both observable and predictable. Various biotic and abiotic factors
influence the succession of ecological communities.
Primary Learning Outcome:
Students will learn the definition of ecological succession and will be able to differentiate
between primary and secondary succession.
• How can environmental disturbances affect succession
• Can environmental disturbance ever be beneficial to an ecosystem If so, how
• How predictable is succession in general
Assessed QCC:
• Standard: Uses science process skills in laboratory or field investigations, including
observation, classification, communication, metric measurement, prediction, inference,
collecting and analyzing data.
• 1.1 Designs and conducts a scientific experiment that identifies the problem,
distinguishes manipulated, responding and controlled variables, collects, analyzes and
communicates data, and makes valid inferences and conclusions
• 1.2 Evaluates procedures, data and conclusions to determine the scientific validity of
research.
• Standard: Describes the process of succession in various environmental setting, such as
a lake, an old field, etc.
• 26.1 Identifies the various factors in the physical environment promote changes in
populations.
• 26.2 Identifies the stages that may be required for an ecosystem to reach the final
(climax) stage.
Total Duration:
• 1 hour lecture (definitions of succession, primary vs. secondary, factors affecting
succession, predictability of succession)
• 6 hours lab (set-up of experiment, observation, data recording, conclusions)
Materials and Equipment:
• Five or more pumpkins or large squash
• Digital camera (optional)

Procedures:
Step One
Cut the vegetables in half and place them outside, some in shaded areas, some in sunlight (if
possible) and record preliminary observations, i.e., outdoor temperature, relative humidity, and
rainfall. Students should also describe the initial condition of the squash, such as color, texture,
and firmness.
Step Two
Observe the vegetables over a period of days or weeks. Record the number of different insect
types present. Note any changes to the vegetable matter, and continue to record environmental
data.
• Describe the pioneer organism in this example.
• How is the insect community changing
• What are some ways in which the insect communities could be interacting
• Why do different groups of insects appear at different times
Assessment:
Students can be quizzed or tested over the lecture and lab material. Extensive field notes should
be taken and kept in a separate notebook. The notebooks should be as thorough as possible,
describing the environmental conditions for each day, such as temperature, rainfall, and
humidity. It may be useful for students to sketch the squash (or take digital photographs) so that
changes over time can be documented.. Students should also be tested on the lecture material,
with an emphasis on the definition of ecological succession as well as biotic and abiotic factors
acting on a system.
Extension:
Students can design an experiment to test how the succession of organisms would differ under
different environmental conditions. How do the results vary in warm weather vs. cool Would
the experiment be affected by unusually heavy rainfall or drought