A few days ago I did a post featuring a fossil of a creature called Archaeopteryx, famed for having traits both bird- and dinosaur- like: it filled in a gap in the evolutionary record. The photo you see here is of the paleo-biologist Neil Shubin with a model of a creature whose fossils he found. Its name is Tiktaalik, and its claim to fame is that it represents a similar place in our fossil records between fish- and land- animals.
Shubin’s work has focused on the most primitive origins of our most sophisticated human systems. For instance, in his book and documentary _Your Inner Fish_, Shubin gives an example of the evolution of male testes. In fish, from whom we evolved, the gonads lie up near their hearts. As primates and humans developed, however, the sperm needed cooler temperatures, and so the gonads descended until of course they became testes lying outside the gut. The price of this movement was, however, not without costs: the area of the pelvis around human testes is decidedly more vulnerable than the area around a fish’s gonads. And this weakness explains why men are relatively prone to hernias.
Source(s): Neil Shubin’s documentary (about the eponymous book) _Your Inner Fish_ can be found on YouTube. Photo: Nathaniel Chadwick: tangled bank studios.
