pdf("solomon.pdf") sol <- read.fwf("http://www.stat.ufl.edu/~winner/data/solomon.dat", width=c(20,3,8,8), col.names=c("island", "species", "area", "dist")) attach(sol) logarea <- log(area) dist <- dist+0.001 species.mod <- nls(species ~ (b0+b1*log(area))*exp(-(dist^b2)/(b3*area^b4)), start=c(b0=35,b1=5,b2=1,b3=1,b4=1)) summary(species.mod) dist.grid <- 0:350 plot(species ~ dist) lines(dist.grid,predict(species.mod,list(area=0.5,dist=dist.grid)),lty=1) lines(dist.grid,predict(species.mod,list(area=2,dist=dist.grid)),lty=2) lines(dist.grid,predict(species.mod,list(area=10,dist=dist.grid)),lty=3) lines(dist.grid,predict(species.mod,list(area=1000,dist=dist.grid)),lty=4) dev.off()