Activity 9: Teaching Tips
Using Blackline Master Ecology 9.3: Effect of Detergent and Lawn Fertilizer on Algal Growth discuss with the students what characteristics they should look for
in their jars to describe the developments that are occurring. Emphasize the importance of keeping good records. To prevent loss of experimental results,
require the groups not to have just one student keep records but that every single member should do so.
Ask the students what purpose lightning has. Students may not know the role
that lightning has in the nitrogen cycle. Tell them that the lightning’s energy destabilizes the atmospheric nitrogen, making it react with oxygen to form
NO3– that can then be used by the plants.
Before discussing the nitrogen cycle, assign The Nitrogen Cycle (pp. 569-572)
in the BioTalk reading for homework.
Ask the students to make Cornell Notes on those pages.
Encourage them to have their homework completed by telling them that
they can use their notes in a quiz the next day.
Using Blackline Master 9.1: The Nitrogen Cycle, have the students work as partners by making two students who are seated close to each other move their desks so that they are facing each other. Give the partners two pairs of scissors, glue, and a white paper. Have them construct The Nitrogen Cycle with the aid
of their Cornell Notes.
Discuss the two kinds of bacteria:
- Aerobic that use oxygen and anaerobic that do not.
It is the anaerobic bacteria (denitrifying bacteria) that change the nitrates into nitrites and ultimately back to atmospheric nitrogen. This action denies the grass with the much-needed nitrates.
The magazine was referring to the lack of oxygen that allowed the anaerobes
to play their role.
Emphasize that there are two cycles in the phosphorus cycle:- Long term and short term.
Explain the two cycles separately and then link them together in your discussion.
Using the Blackline Master 9.2: The Phosphorous Cycle, ask the students the following: - There are two smaller cycles in this cycle: Long term and short term. What cycle do you belong to and why?
Discuss that some biologists do not consider algae as a plant. They are
listed under the Kingdom Protista for their lack of roots, stems or leaves.
If the students are through with their experiment, you can give them a quiz
by asking this question:
- Explain the picture on page 574, using the results of your experiment
with the detergent and lawn fertilizer.
You may show a video on the “kaingin” (slash and burn) system of agriculture
in which the farmers burn the forests to clear the land for planting purposes.
When the soil becomes poor and fails to yield enough crops, the farmers go
to another part of the forest to start the process all over. |