A hugely successful fish in evolutionary terms, with a lineage dating back more than 400 million years, the shark is under relentless attack from humans themselves.

The alternative view, that evolutionary changes tick along gradually, suggests mutations would accumulate incrementally as time goes by, independently of how many new species a lineage spins off.

Reincarnation was not the natural evolutionary process of the original human lineage, but it has been operational for over 5 million years.