Washington, June 15 (ANI): While ecologists generally accept the premise of Darwin's hypothesis, which states that the struggle for existence is stronger between more closely related species than those distantly related, a new study has provided 'strong support' for the theory.
It contains the strongest direct experimental evidence yet to support its validity.
"We found that species extinction occurred more frequently and more rapidly between species of microorganisms that were more closely related, providing strong support for Darwin's theory, which we call the phylogenetic limiting similarity hypothesis," said Lin Jiang, an assistant professor in the School of Biology at Georgia Tech.
Jiang and his team conducted experiments with 10 common ciliated protist species in artificial, simplified ecosystems called microcosms.
"We selected bacterivorous ciliated protist microorganisms for this study because they rapidly reproduce, allowing us to examine species co-existence over multiple generations in a closed system during a period of a few weeks, which wouldn't be possible if we were testing the hypothesis with plants or animals," said Jiang.
The study results showed that all species survived until the end of the experiment when alone in a microcosm. However, in more than half of the experiments in which protists were paired together, one of the two species dominated, leading to the extinction of the other species.
The researchers found that the frequency and speed of this extinction process-called competitive exclusion-was significantly greater between species that were more closely related.
"We hope our experimental validation of the phylogenetic limiting similarity hypothesis in microorganisms will encourage other ecologists to conduct additional studies with other types of organisms to further validate Darwin's hypothesis," added Jiang.
The study has been published in the journal Ecology Letters. (ANI)
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