00462nam a2200097Ia 4500 170517s9999 xx 000 0 und d Extinctions More than 90 percent of all organisms that have ever lived on Earth are extinct. As new species evolve to fit ever changing ecological niches, older species fade away. But the rate of extinction is far from constant. At... Science. http://topdocumentaryfilms.com/extinctions/ 334218 334218 0 0 0 CL CL 2017-05-17 0 2017-05-17 00:00:00 2017-05-17 DF