Unit C

Module 5 ~ Lesson 4

 Limiting Factors


Photosynthesis provides organisms with the energy they need to stay alive. All organisms, producers and consumers, are subjected to limiting factors in their environments.  A limiting factor is an environmental factor that limits or controls the survival and function of an organism.  What happens if limiting factors such as low light intensity, low carbon dioxide levels, or extreme temperatures, inhibit the rate at which photosynthesis can occur? How would inhibited photosynthesis affect consumers that depend on plants for energy and for the oxygen needed for the process of cellular respiration?

 Rate of Photosynthesis

In this lab, you will study photosynthesis in a variety of conditions. You will vary light intensity, carbon-dioxide levels, temperature, and the colour (wavelength) of light in order to find out how each factor affects oxygen production. Oxygen production is used to measure the rate of photosynthesis. 

Which conditions produce the best rate of photosynthesis? How do limiting factors affect the rate of photosynthesis?

  1. Read pages 180 to 181 in your textbook.
  2. Open and print the lab activity sheet. If you do not have access to a printer, use the Word or Google document.
  3. To access the lab, go to this page.
  4. Follow the instructions on the lab activity sheet.
  5. Contact your teacher with any questions. Your lab activity sheet does not need to be submitted to your teacher. Keep it for your notes and further study.