I remember seeing some of this while snorkeling in the Caribbean on my honeymoon, and have explored tidal pools on both the Atlantic and Pacific coasts of Canada. Underwater is a completely different and sometimes eerie world.

It looked like some sort of tidal pool, the biggest one i've seen. The sand will fill in eventually, and there will be plenty of smaller tidal pools for nature to live in.

At the very least, the moon causes tides, so all those types of life that depend on tidal pools would not exist without it and would probably become extinct if the moon moved away. But more imporantly, if Earth had no Moon, its axis of rotation would wander chaotically, rendering the emergence and survival of life more difficult (according to the European Space Agency)

On life after 40: I think rembar is right in that it must have some kind of evolutionary explanation. Socrates, for example, had rather little access to modern medicine, but still had to be actively killed in his late 70's to stop him "corrupting" the youth of Athens.