Your Inner Fish

Your Inner Fish

If someone called you a shark, a worm or a sponge, you might take offense. But as Neil Shubin argues in Your Inner Fish, there’s more truth to these comparisons than one might suspect. How so? It turns out that many features of our bodies have their origin in creatures that evolved prior to us within evolutionary history.
Shubin is well qualified to explore this topic—in 2006 he and colleagues stunned the world with the discovery of Tiktaalik, a 375-million-year-old “transitional species” part fish and part amphibian. In recounting the story of Tiktaalik’s discovery, Shubin notes that its fins contain bones that correspond to our upper arm, forearm and even parts of our wrist. The joints are there too—this is a fish with shoulder, elbow and wrist joints. All inside a fin with webbing!
Connections like these abound between human and animal anatomies. For example, lungfish fins have a single bone at their base that attaches to the shoulder—a direct analog of the humerus, the bone that attaches our upper arm to our shoulder. Descending to the scale of the genome, we find that a gene called Sonic hedgehog helped shape the architecture of limbs in chicken, frogs and mice long before it served the same function in humans. Sonic hedgehog also influences the development of shark, skate and human skeletons in analogous ways.
Think your evenly aligned teeth are special? Sorry—the precise way in which our upper and lower teeth come together is mirrored in primitive reptiles known as tritheledonts. And the layered structure of our teeth is evident in ostracoderms, a type of fossil fish that lived 500 million years ago. And so it goes: bones that support shark jaws are used in humans to swallow and hear. Versions of our body-plan genes are present in sea anemones. And primitive sponges called placozoans contained cell communication tools we see in our own bodies. Even more surprising, human-animal links explain why we suffer from hiccups and hernias.
Your Inner Fish illuminates the intimate links between the anatomy of humans and other animals.

Hardcover: 240 pages

Publisher: Pantheon Books ( December 17, 2007 )

Item #: 59-6701

ISBN: 9780375424472

Product Dimensions: 5.5 x 8.25 x 0.0 inches

Product Weight: 11.0 ounces