Parasite Rex: Inside the Bizarre World of Nature's Most Dangerous Creatures

I had been looking forward to reading through this book as soon as I had acquired it. While I had just read a book by this author, Carl Zimmer, I went ahead anyway and selected it from my collection (AKA: the towering pile of books were my body will one day be found, crushed). I have to admit that I have a bit of a fascination with the concept of a parasite. An organism that has adapted itself to live off of or within another organism. Such specialized examples of evolution have always caught my attention.

In this book Carl Zimmer reveals a truth about life that is often overlooked or perhaps purposely ignored. The fact that the number of parasite species are not some minority of organisms but in fact makes up the majority of species. For those of us living in the developed world, parasites have been moved to an oddity of underdeveloped regions. But humanities evolution has been shaped by parasites. Not just humanity but so much of the courses of evolution have been affected by parasites. Carl Zimmer even puts forth a recent argument that has developed that has parasites being the reason life evolved sex. Another shows that the various displays found in nature for attracting mates, such as the peacock's tail feathers or the dewlap of many lizards, are in fact displays to show that they are the most resistant to parasites (how else could they expend their energy this way when it would otherwise be siphoned off?). Suddenly all of evolution starts to show the signs of parasitic influence.

Parasites have found their way into every life form for so long that not having parasites is actually something out of the ordinary. In fact without parasites to keep in check, the human immune system that evolved alongside countless invaders can even go into overdrive in their absence. Such reactions display as allergies, colitis, and Crohn's disease.

Not only are parasites an accepted part of life for, well, the rest of life as a whole, it is a crucial one. When an ecosystem is unhealthy, it is the parasites that are affected first as they are the de facto top predator and thus they are hit the hardest when an ecological web is disturbed. Researchers are now starting to use the number of parasites as a sign of the health of an ecosystem, as if they are thriving then all the other strands must be in order. In many places the parasites act as a regulating system so that no one species ever becomes so successful that it pushes the ecosystem out of balance.

In all, Parasite Rex was a book that made me glad for once that I'm an insomniac as I was not willing to stop reading even if sleep is something humans are supposed to require. The way it has expanded my understanding of the intricate interactions of life on this planet is something that shall forever shape my view. It is like having a key piece of the puzzle put into place that you did not even know was missing.