Whoops ... :-) > Hence, the very factors which make a creature compete well for > resources and produce relatively many offspring may be what dooms > its > ancestors to extinction. "... ancestors ..." should be "descendants" or perhaps, "ancestral line. You knew what I meant. Russell -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist