Proving Darwin Right: New Study Supports Hypothesis That Competition Is Stronger Between More Closely Related Species (http://www.sciencedaily.com/releases/2011/06/110614101127.htm)
QuoteScienceDaily (June 14, 2011) — A new study provides support for Darwin's hypothesis that the struggle for existence is stronger between more closely related species than those distantly related. While ecologists generally accept the premise, this new study 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...
Interesting research, worth a read.