The North American horseshoe crab is a survivor.  Comparing horseshoe crab fossils to the living creature suggest It has  changed little over time, even through major environmental changes which may have caused the extinction of many other creatures.  A recent conservation campaign in Delaware Bay encourages people to "just Flip 'em" when they see a horseshoe crab turned upside down by the waves.  But the horseshoe crab already has a perfectly good solution to this problem in its' long, rigid tail.  Will such a campaign make any impact on horseshoe crab survival?  The jury is still out. But perhaps we can learn something about ourselves from this example.  Uplook Magazine September-October 2009, p.4.  References: Royal Ontario Museum, "Oldest Horshoe Crab Fossil Found, 445 Million Years Old,"  Science Daily (Feb 8, 2008); JH Mattei & MA Beckey, "The Horseshoe Crab Conundrum: Can we Harvest and Conserve?"  Wrack Lines 8:1 (Spring/Summer 2008); Microsoft; Encarta Online Encyclopedia 2009, s.v. "Extinction (biology)."