How many generations has your family been in the land you call home?
How to define family?
How to define home?
If we start the definition of life with replicating nucleic acid molecules then the numbers are interesting.
It seems likely it took about a thousand billion generations of RNA molecules to generate the first cellular life.
It seems likely that it took about half that many generations of cellular life to get to the stage of self replication (no longer reliant on the heating and cooling or agitation supplied by the external world to complete a generation).
It seems likely that it took a similar number of generations to get from the first self replicating cell to the first multicelled organism with sexual reproduction.
To get from there to human beings was just a hundred million generations.
To get from the first human to the most recent common ancestor of all of us just 400 thousand generations.
To get from that most recent common ancestor in Africa to every human alive today – just 4 thousand generations.
So for me, about 2 and a half trillion generations from inorganic chemistry to me and all other life alive on this planet I call home today.
Really good question.
And no its not just an artefact, evolution really has sped up due to several innovations.
First and most important was sexual reproduction.
Sexual reproduction allows innovations in different cell lines to recombine with each other.
This alone increases the rate of evolution by many thousands of times.
Another mechanism that has increased the rate of evolution is the evolution of mechanisms to increase the rate of mutation in selected areas of the genome.
Another mechanism that has increased the rate of evolution is the programmed death of individuals. Having individuals die after a reasonable period of reproduction significantly increase the rate of evolution, as it stops the drag of particularly powerful individuals remaining in the gene pool a very long time. This combination of aging and sexual reproduction has significantly increased the rate of evolution.
Once evolution jumped to the realm of ideas/behaviour (memes) then the game changed again, by many orders of magnitude, and with the aid of digital memory and communications, continues to increase exponentially.