Tuesday, January 21, 2014

Patterns in Nature: Sand Dollars

At New Years I was walking along the beach at New Brighton with a friend, and we kept finding broken sand dollars on the sand... Sand dollars are a kind of sea urchin with flattened shells.

This one had two segments still stuck together, so shows the patterns better
When whole, the sand dollar consists of 5 segments, but we mostly found only single segments, but one or two with two segments still attached together. We thought the patterns on their shells were pretty neat. Below are some of the patterns in close up.





We also found one segment that had been broken to give a cross section of the inside...

Pretty, huh? 

If you want to learn more about sand dollars, This  page has some good info plus some cool videos of living sea urchins and sand dollars.