there have been a great number of times when the diversity of species has bottlenecked.
the Cretaceous/Tertiary extinction reduced biomass by about 65% and biodiversity by 75%, and the Permo/Triassic extinction was even worse at 80% of biomass and 90% of biodiversity.
notice that biodiversity always dips more than biomass which is because the species least adapted to the changing environment go extinct wheras the remainder suffer but survive. and regardless of this new species emerge to fill ecological niches and biomass and biodiversity recover.............. until next time.
Bookmarks