So, on what finger do you wear a promise ring? In the USA and the UK, the ring finger (fourth finger) of the left hand holds the greatest significance; engagement rings and wedding rings are worn on this finger almost without exception.
In biology and ecology, extinction is the end of an organism or of a group of organisms (taxon), normally a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and recover may have been lost before this point. Because a species' potential range may be very large, determining this moment is difficult, and is usually done retrospectively.
A mass extinction is when more than three-quarters of the worldâs species become extinct in a short frame of time. Total up the numbers in these five mass extinctions and we have lost 99 percent of the Earthâs species â and thatâs without human intervention.