Global Cooling Caused Diversity of Species in Orchids, Confirms Study
Published:27 Aug.2023 Source:University of Bath
Scientists at the Universities of Bath and York studying almost 1500 species of terrestrial orchids, have found that rather than evolving gradually over thousands of years, these plants diversified relatively quickly due to changes in global temperature. Analysing thousands of DNA sequences, they compiled a family tree showing relationships between the species, and used statistical models to test how changes in climate during the Earth’s history might have driven the formation of new species. They then tested the different possible models using more than 2.5 million records of geographical distributions.
They found evidence that most of the species appeared during the last 10 million years, coinciding with global cooling, as calculated from geological records. Modelling the probability of different drivers of speciation suggested that global cooling is 700 times more likely to influence speciation of orchids than time alone.
Dr Jamie Thompson, first author of the paper and researcher at the Milner Centre for Evolution at the University of Bath, said: “We found this correlated with global climate change, so that more species emerged as the climate cooled, giving the first evidence of global cooling driving speciation in these plants.” The researchers also found that the speciation rate -- how quickly new species arise -- wasn’t dependent on how many species there were to begin with.