A phyloGENETIC tree is not the same thing as a taxonomic tree, which is what Cal described. rRNA and molecular studies are used in phylogenetics to determine relations between species.
1 As the light intensity increases, the rate of photosynthesis increases. 2  However, the rate will not increase beyond a certain level of light intensity. 3  At high light intensities the rate becomes constant, even with further increases in light intensity, there are no increases in the rate.
Limiting factors. Three factors can limit the speed of photosynthesis - light intensity, carbon dioxide concentration and temperature. Without enough light, a plant cannot photosynthesise very quickly, even if there is plenty of water and carbon dioxide. Increasing the light intensity will boost the speed of photosynthesis.