Discussion Group Report

Dr. Neil Shubin is a paleontologist and teaches comparative anatomy at the University of Chicago. He recently discovered a fossil that bridged the evolutionary gap between fish with fins and amphibians with limbs, also called "tetrapods." It is a 375-million year old fossil discovered in the Canadian Arctic Islands. He named it Tiktaalik. It has scales like a fish, eyes on the dorsum of it's head like early amphibians, and a "specialized fin" which looks externally like a fin but contains the rudimentary bones of a tetrapod arm. The humerus (upper arm), radius, ulna (lower arm), carpal bones (wrist), and phalanges (fingers) in early stages of evolution could be all be identified in the front "specialized fin." It truly is a bridge fossil between fish with fins and amphibians with legs. Based on this find he began writing his most recent book, Your Inner Fish, A journey into the 3.5 billion year history of the Human Body.

In the beginning of the book he tells us about his lifelong interest in finding fossils that bridge the gap between fish and tetrapods. Tiktaalik is truly an intermediate fossil between fish and tetrapods and the fulfillment of a lifelong dream for Dr. Shubin. This fossil "gap" that for so long had been held out by the creationists as a fault with Darwin's Theory of Evolution has now been closed.

Next he explains how we can trace evolution not only in fossils but also with DNA. The molecular biologic history of life on earth is being uncovered at an amazing rate in the past few years. Using the fossil record Shubin explains that our hands resemble fossil fins; our heads are organized like those of long extinct fossil jawless fish. With our recent ability to accurately study, and rather quickly sequence, genomes, we have found that major parts of our genomes still look and function like those of worms and bacteria. For example, the same embryonic "sonic hedgehog" gene tells a fruit fly where to put its front limbs during development, tells a fish were on its body to place the front fins, and also tells the human embryo where to place our arms. In fact, the "sonic hedgehog gene" from a fish, if placed in the top part of the fruit fly head during embryonic development, will produce a fruit fly with a leg coming out of the top of its head, and vice versa. Other examples and evidence outline his case for existence of a "fish within us": teeth in ancient jawless fish that evolved into modern mammary and sweat glands: and genes, which control our eyes and ears, that correspond directly to DNA found in primitive jellyfish.

Dr. Shubin is also taking a swipe at "creation science." From the pages of his book it is clear that if a supreme being were responsible for creating life on Earth, from bacteria to humans, He, She, or It didn't do it flawlessly. Far from being the perfectly crafted handiwork of a deity, our bodies are jerry-rigged patchworks of old bones, cells and genes bolted on to frameworks that creak and groan at every opportunity. Men suffer hernias because their spermatic cords, inherited from ancient fish ancestors, leave them susceptible to gut tissue spilling through muscle walls as the testicles descend from their internal position below the lungs in fish, through the abdominal wall, into their external position in the human scrotum. The evolution of the voice box left us susceptible to aspiration or "café coronaries." Our diaphragms and the position of the phrenic nerve leave us susceptible to hiccups. Amphibians do not have diaphragms and they use electric signals generated in their brain stems for rhythmic gill breathing. These leftover brain signals in humans are transmitted through the phrenic nerves to our evolved diaphragms and result in hiccups.

Humans have too many un-intelligent designs to be a product of "intelligent design." We shouldn't be surprised, says Shubin, "We were not designed rationally, but are products of a convoluted evolutionary history."