AP BIOLOGY

Detailed explanation-1: -Judging from the fossil record, the baseline extinction rate is about one species per every one million species per year. Scientists are racing to catalogue the biodiversity on Earth, working against the clock as extinctions continue to occur.

Detailed explanation-2: -When species vanish, benefits to humanity can be lost, too – from economic opportunities related to ecotourism to keeping in check populations of species that can spread infectious disease. The UN report estimated that as much as $577 billion in annual global crops are now at risk from loss of pollinators.

Detailed explanation-3: -A mass extinction event is when species vanish much faster than they are replaced. This is usually defined as about 75% of the world’s species being lost in a ‘short’ amount of geological time-less than 2.8 million years.