Then there is also the evolutionist's reply to this question: because the ocean has a lot more calcium than iron, (in ppm Ca: 400, Fe: 0.003[1]). So all the evo

Then there is also the evolutionist's reply to this question: because the ocean has a lot more calcium than iron, (in ppm Ca: 400, Fe: 0.003[1]). So all the evolved mechanisms from shells to (cuddle) bone were in place due to available materials long before any other possibility presented itself. [1] http://www.seafriends.org.nz/oceano/seawater.htm http://www.seafriends.org.nz/oceano/seawater.htm