The world’s sixth mass extinction began about 40 years ago, with humans contributing to the loss of biodiversity, according to a new study in the journal Science Advances. The authors call for fast action to conserve remaining threatened species, populations and habitat, but warn that the window of opportunity is rapidly closing. mass extinction is a relatively sudden, global decrease in the diversity of life forms. it’s when three out of four familiar species disappear from the face of the earth in a short time period. Already extinct is the Pinta Island tortoise, famously represented by a single male individual, “Lonesome George,” for many years. He died on June 24, 2012, without siring any offspring. With him went an entire subspecies of tortoise.
— source discovery.com