niches

He added that while there have always been niches of people with extreme views, they have tended to remain in that niche.

In modern ecosystems, that process has led closely related birds of paradise to develop different displays while sharing ecological niches.

"Cichlids are known for filling a huge diversity of different ecological niches and being able to adapt to changes in their environment," they said.

"Some of these feline predators, particularly the sabre-toothed species, rapidly occupied fairly specialised niches, which made them more susceptible to extinction," explains Dr Tamagnini.

Their proteomes have already attained an optimal state through the course of evolution, where further major changes are neither advantageous nor necessary for the organisms to survive and adapt to their current niches.