Question: Create a log (dose) curve for your ecotoxicity results. Plot your relative algae fluorescence measurements against the different log (atrazine concentrations) you used. What type of curve do you see (hint: look at the shape of the curve)? How can you explain the shape of the curve? Is the shape of the curve what you expected to see? The EC 50 ("effective concentration 50") is defined as the concentration that induces an effect in 50% of the test population. Locate the EC 50 on your plot. What effect are you looking for in this experiment?