10.6 Galpagos Islands (Data file: galapagos) The Galpagos 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.

10.6 Galapagos Islands (Data file: galapagos) The Galapagos 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 Table 10.6 Galapagos Island Data Variable Description Island Island name NS Number of species ES Number of endemic species (occurs only on that island) Area Surface area of island, hectares Anear Area of closest island, hectares Dist Distance to closest island, kilometers DistSC Distance from Santa Cruz Island, kilometers Elevation Elevation in m, missing values given as zero EM 1 if elevation is observed, 0 if missingthe number of species that occur only on that one island ( the Endemic Species ) List 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 . Line complicating factor is that elevation is not recorded for six very small islands. so some provision must be made for this . Four possibilities are ! !' find the elevations : 1 2 ) delete these six islands from the data . (3 ) ignore elevation as a predictor of diversity , or 14'] substitute a plausible value for the missing data . Examination of large- scale maps suggests that none of these elevations