FIGURE 4. 4.1) Scatter plot of alpha diversity and the diversity of k-means habitat types illustrating the strength of this relationship (r = 0.763). 4.2) Global diversity landscape map. The alpha diversity of the entire globe for the most recent 57 m.y. is given by amplitude along the vertical axis, and the fourth dimension of habitat type diversity is given by the color of the peaks. Notice that most tall peaks are also hot colors, which highlights the linear relationship between alpha and habitat type diversity. Longitude ranges from 0° (180°W) to 360° (180°E), and latitude from 0° (90°S) 180° (90°N).