This document summarizes and compares two ecosystems in Puerto Rico: Bosque Seco de Guánica and El Yunque National Forest. It describes the differences between their dry forest and rain forest areas in terms of rainfall, tree size, leaf size, canopy layering, and flora and fauna. The key differences highlighted are the taller trees and greater humidity in El Yunque's rain forest compared to Guanica's drier climate and smaller trees. Threats like overpopulation, pollution and climate change that endanger these ecosystems are also mentioned.