1. The Law of Limiting Factors

2. Aim
To use computer simulations to investigate the effect of different factors on the rate of photosynthesis.
To use analyse secondary data
To report back to the rest of the class

3. The law of limiting factors
Photosynthesis will only proceed at the rate determined by the factor in shortest supply

4. Carbon dioxide Water Light intensity Temperature wavelength
What environmental factors affect the rate of photosynthesis?
Carbon dioxide
Water
Light intensity
Temperature
wavelength

5. How can we investigate the rate of photosynthesis?
Volume of oxygen produced
Volume of carbon dioxide used up

6. 250C
100C

7. Bubbling pondweed
What was limiting the rate of photosynthesis in Expt 1?
Light intensity…. Because increasing the light intensity increases the rate of photosynthesis up to a certain level
If you compare with Expt 2 then we can also conclude that temperature was limiting since increasing temperature also increases the rate of photosynthesis.

8. What was limiting the rate of photosynthesis in Expt 2?
This time we can only be certain that light intensity is affecting the rate.
The fact that the graph levels off at high light intensity suggests that something else may be limiting but we cannot say for certain what it is.

9. What else did you find out?

10. Now investigate limiting factors in more detail
You should complete the practice coursework experiment and questions from your booklet
Remember – The limiting factor is the factor in shortest supply. This will determine the rate of photosynthesis.