What is the average length of time a species exists?

Answer 1

A close study of fungi revealed that thousands of species of bacteria developed and became extinct within a few days. Extrapolating this data, it was suggested that billions of species of bacteria may be created and become extinct before we even knew they were alive. Using this information it was suggested that the average length of time that a species exists is about 2 minutes

Answer 2

I have no idea, but I'll tell you they found bacterias in space and in rocks on earth that came back to life after 2 million years
so you never know