The index of extinction risk for five major groups — birds, mammals, amphibians, corals and an ancient family of plants called cycads — shows an accelerating slide towards oblivion. Depending on which categories are included, the current rate at which species are going extinct is 100 to 1000 times greater than only a few centuries ago. This article titled, Earth Enters Sixth Extinction Event in Half-a-Billion Years, is a must-read one; do not miss it out!