Embryology, or the study of embryos, can help us find plenty of evidence to support the theory of evolution. For example, vestigial structures such as tails or gills in humans can be found in embryos early during their development.
The author presents characteristics of Guyana's desolate and dismal landscape as a means to appeal to those who depended on the sugar production business in order to maintain themselves economically, and thus, demonstrating the importance of sugar. The whole purpose of the passage is to provide ethical evidence from the sugar scheme's current situation, presenting information about the moral consequences of this business' downfall; in this case, the economic backlash in the country of Guyana.