EXPERIMENTAL DESIGN: Read the following experimental
design and identify the hypothesis, variables and control group
below. (5pts)
Data shows that the main results of an El Niño event are increased rainfall and increased temperature of both
the water and the air. You learned that the marine iguanas are tolerant of temperature fluctuations so you rule
that out as a cause of their death. You decide to focus on the increased rainfall. You wonder how the increased
rainfall could affect the iguanas and remember that they must bask on the rocks in order to regulate their
temperature. You decide to create an experiment to see if the rainfall during the El Niño event was heavy
enough to cover up the rocks needed by the iguanas. You hypothesize that IF enough rain fell, THEN that
would cause a significant number of marine iguana deaths. You create an experiment to test your hypothesis.
You create z working models to represent a typical Galapagos Island with identical rock formations. You then
add water to each of the model aquariums. One will receive the amount of water that falls in a typical year
(aquarium #1). The other will receive the amount of water that fell during the El Niño year in question.
(aquarium #2). You observe that 82% of exposed rock in aquarium #2 was covered by water. You then perform
calculations to multiply the average number of iguanas by the space required per iguana to bask. You
determine there was not enough basking rock available for the population.