If, digging in 600-million-year-old rocks, we found the earliest jellyfish lying next to the skeleton of a woodchuck, then we would have to rewrite our texts. The order of fossils in the world’s rocks is powerful evidence of our connections to the rest of life. A sceptic or fence-sitter reading this book would be taken by Shubin through the main lines of evidence almost by stealth. Although it is not one of the aims of Your Inner Fish to convince the reader of the fact of evolution, by going through the areas of fossil study, comparative anatomy, genetics, embryology, etc it is covering much of the same ground as books that do have that aim like Jerry Coyne’s Why Evolution is True or Richard Dawkins’ The Greatest Show on Earth.
He does this both from the perspective of fossil finds – of those fish that lived before Tiktaalik and those early amphibians that came after, showing Tiktaalik’s place in the transition – and from the perspective of genetics and embryology and experiments done in the 90’s on the ‘zone of polarising activity’ (ZPA) on embryonic limb buds.īy now, not even half-way through the book, a few things were becoming clear. Since one of the main things that make the Tiktaalik find important is what it shows about its stage in the development of limbs, Shubin spends a couple of chapters on limb development. The first thing Shubin wants the reader to appreciate is how unlikely it is for animal remains to form fossils to begin with, the difficulty of finding the ‘right’ fossil and why the Canadian Arctic is the best place to search for fossils for the fish-land-animal transition. It was all of this additional information that made Your Inner Fish a joy to read and easy to recommend. In fact, most of Your Inner Fish is not about Tiktaalik directly, but about the science that gives the discovery of Tiktaalik context, that shows its important place in the history of life on this planet and for the eventual evolution of terrestrial animals including humans.
Written by Neil Shubin, one of the co-discoverers of Tiktaalik, instead of diminishing the excitement of the discovery, the science actually magnifies its importance and significance of the discovery. One of the aims of Your Inner Fish is to pull the general reader away from the media hype and provide the facts and science of Tiktaalik and its relevance. The supposed ‘missing link’ between fish and land-vertebrates was popularly described as ‘the fish that could do a push up’ for having the shoulder and forelimb bones usually associated with land vertebrates like early amphibians, while also clearly being a fish. The discovery of Tiktaalik ( Tiktaalik Roseae), a 375 million year old fossil, generated headlines in 2006.
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