4. The clarity of lake water is affected by the amount of phytoplankton (marine plants), soil, clay, and other solids suspended
in the lake. Suppose the concentration of carbon dioxide in the atmosphere changed from 340 ppm to 380 ppm from 1980 to 2005. What effect would this have on the occurrence of the full body plate trait? Explain your answer. Hint: Think about how carbon dioxide is related to photosynthesis. (10 points)
The increase of Co2 in the atmosphere could speed up photosynthesis and allow plants to grow and develop faster. If the rate of photosynthesis increases, more Co2 is absorbed and more oxygen is expelled.
An increase in the plant population means better filtration of the water. If the water isn’t as polluted, natural selection will take its course and the fish may not need to pass the full body plate trait to their offspring.
