World’s biodiversity can be traced to ‘rapid expansions’ in few big group of species

Majority of the world’s biodiversity evolved through a few big groups of species that grew and diversified at an exceptionally rapid pace, a study has found.
Researchers from the US analysed the rates of richness and diversification of species across ‘clades’- groups of multiple species, each of which evolved from a single ancestor.
“Specifically, if we look among the kingdoms of life, among animal phyla (ancestor), and among plant phyla, we find in each case that more than 80% of known species belong to the minority of groups with exceptionally high rates of species diversification,” said John J Wiens, a professor at the University of Arizona, US. The authors said it is considered that a few groups among each species tend to predominate-for example, more than 40% of living insects are beetles, while 60% of birds are passerines (including sparrows), and more than 85% of plants are those that bear flowers.
“Here we show for the first time that most living species do indeed belong to a limited number of rapid radiations: that is, they form groups with many species which evolved in a relatively short period of time,” Wiens said.
The team looked at nearly five million species of plants and animals, including 678 families of land plants, 870 families of insects, 12 classes of vertebrates, along with 17 kingdoms and 2,545 families across all of life. The authors wrote, “We find that among the major clades of living organisms and among land plant phyla and animal phyla, (more than) 80% of known species richness is contained within the few clades in the (top 10%) diversification rates in each group.” Wiens said the results, combined with those from previous studies, also “suggest key traits that might explain these rapid radiations”. (PTI)