Friday, February 3, 2012

Your Inner Fish, My Inner Fish

Finished a good science read this morning by Neil Shubin, Your Inner Fish:  A Journey into the 3.5-billion-year History of the Human Body.  You should check it out.  Shubin’s the guy who discovered Tiktaalik, the missing link between fish and tetrapods.  Here’s a picture of that beast:

 I know, Tiktaalik is quite a doll.  Paleobiology-types were so excited about this fishapod because it had a wrist and a neck, as well as a number of characteristics associated with amphibians, the first tetrapods, likes a flat head with eyes on top of the head.  But, Tiktaalik is still very fish like with its fins and general fishiness.  Your Inner Fish starts out with Shubin’s stories about the discovery of this and other fossils and how paleontologist use geological maps to make educated guesses about where they might find certain types of fossils.  Good field stories.

Shubin makes connections between the limbs and hands of all tetrapods with their earliest fish ancestors.  He covers the connection early biologists make in the 19th and 20th century between life forms based on studying embryonic development.  And he brings us to the amazing discoveries (and potential for discoveries) in the molecular age—how you can find genes that build bodies in mammals in a very similar form in all sorts of other animals and even choanoflagellates, our protist ancestors.

Some of my favorite things from the book:  Teeth appear to have arisen before skeletons and the first skulls were very tooth like.  He called this an “inconvenient tooth,” which I think you’ll agree is hilarious.  Our earlier ancestors had gonads by their heart (like sharks today), but they have since traveled to the nether region, which causes some problems especially for males who are more susceptible to hernias thanks to the gonad’s peregrination.  The end of the book talks about how the design of the early ancestors that has been tinkered with over time causes some design issues.  There are more than a few good pieces of information to have in your toolbox next time evolution comes up with your fundamentalist relations who try to deny the fish (and sponge) within. 

If you haven’t picked it up, it’s worth a read.  My intro biology students should love it and it made me wonder if Shubin’s book might be the preferable way to cover animal diversity.  Also a must read for med-types!  Shubin has some nice descriptions of nerves leaving the skull and explaining why they wend the way they do.  The interconnection between our lives and the lives of all biodiversity are pretty awe inspiring, and Shubin’s book definitely turns on the awe-o-mometer.