(N/A) The history of life on Earth,as revealed by fossil records,shows that large-scale loss of species has occurred previously,even before the appearance of humans.
During the long period of over $3$ billion years since the origin and diversification of life,there have been five episodes of mass extinction.
The 'Sixth Extinction' currently in progress is distinct from previous episodes.
- The primary difference lies in the rate of extinction; current rates are estimated to be $100$ to $1,000$ times faster than in pre-human times,and human activities are directly responsible for this acceleration.
Ecologists warn that if current trends persist,nearly half of all species on Earth could be wiped out within the next $100$ years.
Historical evidence,such as the colonization of tropical Pacific Islands by humans,led to the extinction of more than $2,000$ species of native birds.
The $IUCN$ Red List $(2004)$ documents the extinction of $784$ species,with $27$ species disappearing in the last twenty years alone.