Survival of the Sickest, by author Dr. Sharon Moalem, is a book that discusses why evolution has not allowed for the destruction of certain diseases over the course of human history. Moalem focuses on many deadly inherited diseases, such as diabetes, hemochromatosis, anemia, vitamin d deficiency and high cholesterol. He explains how such diseases are tools that natural evolution has used, and still uses, to increase the likelihood of human survival. Moalem explains how these genetically and environmentally influenced diseases helped fight against other more life threatening illnesses such as, the bubonic plague in the middle ages, the malaria parasite and certain regions with less sunlight relating to vitamin D deficiency. The overall idea…show more content… This allows all readers of any background to understand the importance of genetics and stay engaged in the reading. The casual writing style allows a basic comprehension of the complex medical language involved with genetics. For example, when describing how humans evolved to fend off diseases better than other species, he writes how animals with a greater risk of being eaten evolve to live shorter lives and reach adulthood faster. Or how diabetes was influenced by cold weather in northern Europeans during the ice ages to increase blood sugar concentrations. Diabetes was a beneficial adaptation to humans living during the ice age because sugar is a natural anti-freeze the increases body temperature and prevents freezing. Another example is how people with Hemochromatosis were protected against the bubonic plague due to their body’s irregular iron regulatory system causing abnormal iron concentrations in the blood. The Y.pestis bacterium responsible for the plague depends on normal iron concentrations in the blood to properly exploit itself and cause illness. This is why half the population without hemochromatosis died and how this currently unbeneficial disease was passed down generations. These subjects can get far more complicated and but the basic descriptions provides a good understanding of the big