Galápagos Islands (Data file: galapagos) The Galápagos Islands off the coast of Ecuador provide an excellent laboratory for studying the factors that influence the development and survival of...

Galápagos Islands (Data file: galapagos) The Galápagos Islands off the coast of Ecuador provide an excellent laboratory for studying the factors that influence the development and survival of different species. Johnson and Raven (1973) have presented data in the file galapagos, giving the number of species and related variables for 29 different islands (Table 10.6). Counts are given for both the total number of species and

the number of species that occur only on that one island (the endemic species). Use these data to find factors that influence diversity, as measured by some function of the number of species and the number of endemic species, and summarize your results. One complicating factor is that elevation is not recorded for six very small islands, so some provision must be made for this. Four possibilities are (1) find the elevations; (2) delete these six islands from the data; (3) ignore elevation as a predictor of diversity, or (4) substitute a plausible value for the missing data. Examination of large-scale maps suggests that none of these elevations exceed 200 m.