http://blogs.smithsonianmag.com/hominids/2012/06/the-paradox-of-the-nutcracker-man/ Meet the members of the tangled human family tree Thu, 31 Jan 2013 17:56:50 +0000 hourly 1 http://wordpress.org/?v=3.4 http://blogs.smithsonianmag.com/hominids/2012/06/the-paradox-of-the-nutcracker-man/#comment-694 Rob Gargett Fri, 29 Jun 2012 14:02:14 +0000 http://blogs.smithsonianmag.com/hominids/?p=1403#comment-694 Hi, Erin, I can offer one suggestion as to why P. boisei's teeth look like they're on steroids. We know, from equid evolution, that habitual chewers of grass over evolutionary time develop convoluted chewing surfaces that maximize the enamel at the contact between the teeth and the silicates in their diet. They also develop really high crowns, which continuously erupt as the grasses wear down the chewing surfaces. If P. boisei was indeed subsisting on grasses it would have put heavy selective pressure on the ability of the teeth to resist attrition. Without the luxury of tens of millions of years in which to evolve the kind of teeth we see in horses and certain microfauna, it's plausible to think that a very small change in the P. boisei genome, as little as a single point mutation in a regulatory gene, could have resulted in an allometric change in tooth size as a way of maximizing the enamel surface. This, in turn, would have lengthened P. boisei's dental use life, which, by contributing to a longer life for the entire organism, fed *cough* directly back to the reproductive success of the individual and the longevity of the species. Voila! Thanks for what you do. Rob Hi, Erin,
I can offer one suggestion as to why P. boisei’s teeth look like they’re on steroids. We know, from equid evolution, that habitual chewers of grass over evolutionary time develop convoluted chewing surfaces that maximize the enamel at the contact between the teeth and the silicates in their diet. They also develop really high crowns, which continuously erupt as the grasses wear down the chewing surfaces. If P. boisei was indeed subsisting on grasses it would have put heavy selective pressure on the ability of the teeth to resist attrition. Without the luxury of tens of millions of years in which to evolve the kind of teeth we see in horses and certain microfauna, it’s plausible to think that a very small change in the P. boisei genome, as little as a single point mutation in a regulatory gene, could have resulted in an allometric change in tooth size as a way of maximizing the enamel surface. This, in turn, would have lengthened P. boisei’s dental use life, which, by contributing to a longer life for the entire organism, fed *cough* directly back to the reproductive success of the individual and the longevity of the species.
Voila!
Thanks for what you do.
Rob

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