Thursday, April 27, 2006
Why are our reproductive organs are coupled to our organs of excretion?
"In the pre-Cambrian period, about 600 million years ago, our worm-like ancestors had a central task to perform: reproduction. This involved shedding sperm and eggs into the water, nothing more, and they co-opted the openings and apparatus that they already had handy for excretion to do the job. Shedding gametes, shedding feces -- similar tasks, right? That expedient sharing of those two functions had long-term consequences we live with right now: Our reproductive organs are coupled to our organs of excretion, which later also got tangled up with our hind limbs.
Now we have to deal with yeast infections and a pelvis that doubles as both a birth canal and a base for posture and walking.
>"What if that worm-like ancestor instead used its other body opening, the mouth, to expel gametes? Reproductive function would be moved forward, away from other messy, but necessary functions. Of course, it would mean that a kiss would be fraught with major new connotations and consequences, but I think we could cope."
>- PZ Myers, biologist and associate professor at the University of Minnesota, imagines a different path in human evolution, from the essay Remaking Humanity.
This raises an interesting question: Why would an "Intelligent Designer" couple our reproductive organs to our organs of excretion?
That doesn't sound like an optimal design, and seems much more like an odd accident of evolution than a planned-from-scratch creation.
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