EXERCISE 3: Limits to Plant Growth

The three main factors that influence plant growth are temperature, the availability of water, and sunlight. Scientists refer to these as “limiting factors” to plant growth. If each of these factors is available in abundance, then plants will generally thrive. But if one or more of these factors is very low, then often plant growth is limited, or even halted.

Below you will see a movie showing three different global data sets. Each frame in the movie shows a one-month average of data for every month in 2001. The first image shows exposure to sunlight at the surface, or “solar insolation” (in kilowatt hours per square meter per day). The second image shows land surface temperature (in degrees Celsius). The third image shows rainfall (in millimeters per day). Hit “Stop” to pause and “Play” to continue the movie; or you can pick a particular month by clicking among the row of boxes at the top. Now, take a few minutes to examine these global data sets:

Questions to consider:

1. Based upon these global-scale movies of rainfall, surface temperature, and exposure to sunlight (or “insolation”), make a chart of the values for each of these measurements for Panama for each month of the year. (NOTE: at this coarse resolution, it may be challenging to focus on a country as small as Panama, so just make your best estimate based on what you see in the images.)
2. Which of these limits to growth is the most important for the plants in Panama? Why do you think so?
3. Do you think this JASON Expedition is taking place during the high or low growing season?

Recommended further reading:

1. Global Garden Gets Greener

 Exercise 2  |  Exercise 4