Talk:Extinction

These two sentences, specifically the last one, The significance of extinction for the General Theory of Evolution is that an enormous number of kinds of organisms must have lived in the past, in order to have given rise to the number of organisms now living. For this kind of evolution to be credible, many kinds must have become extinct, far more varieties of organisms than are now living.

I cannot make out what is trying to be said, can anyone help? Thanks! --Tony Sommer 01:24, 4 April 2007 (EDT)