Answers to Figure Legend Questions

FIGURE 1.4 Estimating from the graph, about 88% of tadpoles in the control group survived, and 0% of them had deformities. Since there were 35 tadpoles in the control group, this indicates that 31 (0.88 ? 35) of the tadpoles in the control group survived, and none had deformities.

FIGURE 1.5 The results for cages from which Ribeiroia was excluded show that pesticides acting alone do not cause frog deformities. The results for cages exposed to Ribeiroia show that pesticides do affect frogs, since the percentage of frogs with deformities was higher in ponds where pesticides were present. However, the results do not indicate how pesticides caused that effect.

FIGURE 1.6 By comparing results from the controls with results from treatments in which pesticides were added, the investigator could test whether addition of a pesticide affected either the immune system response (number of eosinophils) of the tadpoles or the number of Ribeiroia cysts per tadpole. The intent of the “solvent control” was to check for possible effects of the solvent in which the pesticide was dissolved.

FIGURE 1.11 Producers take up nutrients such as nitrogen from the environment and use them for growth (step 1). The nitrogen in the producer's body may then be transferred to a series of consumers: to an herbivore that eats the plant, a carnivore that eats the herbivore, a second carnivore that eats the first, and so on (step 2). Eventually, however, the nitrogen is returned to the physical environment when the dead body of the organism containing it is broken down by decomposers (step 3).