Question

how many times in the history of earth has the number of species dropped drastically

Answer 1

There have been 5 mass extinction events in Earth's history.  Many scientists are even predicting that we're on track for a future 6th mass extinction!

Answer 2

Answer: There have been 5 major major mass extinctions.

Explanation: From the last 4.6 billion years when the earth was formed there has been almost 5 mass extinctions that has lead to mass destruction of species. There was a huge loss of species in every mass extinction that has occurred till date.

These 5 major mass extinctions events are as follows.

• Cretaceous-Tertiary Mass Extinction

• Triassic-Jurassic Mass Extinction

• Permian Mass Extinction

• The Devonian Mass Extinction

• The Ordovician mass extinction