Episodically a book is written of such profound importance that it not only encapsulates and defines a subject, but transforms our under-standing of it as well.
Such is "Evolution's Witness," by Professor Ivan Schwab M.D., at once both magisterial treatise and kaleidoscopic visual treat on the subject of the evolution of the eye. Dr. Schwab has managed, apart from being a Professor of Ophthalmology at the University of California at Davis where he is an ophthalmologic surgeon and well-published and internationally recognized basic and clinical research scientist, to have found the time, focus and diligence to comb the world's literature, communicate with leading authorities in the fields of paleontology, invertebrate and vertebrate biology, comparative anatomy and physiology, collate hundreds of splendid color photographs, microphotographs and histopathology images, and bring to bear an enormous quantity of wide-ranging scientific discourse on how eyes have evolved over the eons, and in so doing, to explicate how the eye is indeed the "visual witness" of the story of evolution.
For years, it had been argued that the complexity of the eye was a reason for some kind of intelligent design in its creation,that the eye could not have developed simply from a combination of time and natural selection. This book, much as Richard Dawkins' seminal work The Blind Watchmaker, is implicitly a paean to and defense of the concept which Darwin championed, that over an impossible-to-comprehend period of time measured in the billions of years and often by only subtle mutations and changes responding to natural selection, nature actually could, and did, design, refine and re-design the eye as a response to predation, biochemistry, environment, natural catastrophes and extinctions. In Doctor Schwab's words, "Sensory systems, especially visual systems, will continue to be among the premier forces of evolution because of the advantage they afford species."
|Trilobite eye (Metacanthina sp.)|
Note the numerous ommatidia.
Trilobite eyes fossilize easily because
they contain calcite.
Dr. Schwab masterfully engages the reader in this wondrous chronology and by augmenting the narrative with these stories, replete with vivid color illustrations, he does so compellingly well, as opposed to robotically listing a myriad organisms and examining their visual apparati. And in reality, he tells two interweaving stories: the story of evolution as seen through the specific lens of ocular evolution, and the story of many of the world's creatures, and the development of their unimaginably divergent and fascinating eyes, which evolved in response to Darwinian natural selection.
This book is hard to put down. It will be both a wonderful tome to pick up frequently and select a chapter at random to read on the remarkable and colorful story of life and vision, as well as a serious, deeply referenced academic resource for ophthalmologists, visual scientists and readers of all stripes who are intrigued by how it is that our eyes, and the eyes of countless creatures both present and extinct, have come to be.