Do certain species survive at the expense of others? The question of competition between the species was at the heart of a premise first explored by Charles Darwin in 1859. A new study lends further support to this aspect of Darwin’s still-controversial theory of natural selection.

Darwin’s  “On the Origin of Species by Means of Natural Selection” outlined a revolutionary approach which would eventually become known as evolutionary biology.  Today, more than a century later, scientists continue to try to either prove or disprove Darwin’s theories.

One of Darwin’s hypotheses explored the role  competition played in determining the survival of a species.  A recently released study led by Lin Jiang at Georgia Institute of Biology – otherwise known as Georgia Tech – supports this theory.

Although most scientists already tend to accept Darwin’s premise, this new study presents the strongest direct experimental evidence yet to support its validity.

Dr. Jiang’s team chose to study 10 common species of the ciliated protist – or protozoa microrganisms – because of their ability to reproduce. This allowed the research team to examine the co-existence of the species over multiple generations in just a few weeks.

The research team conducted their experiments within specially constructed, artificial and simplified ecosystems called microcosms.

When left alone in a microcosm, all of the species survived until the end of the experiment. However, when two species were paired together, one dominated in more than half of the experiments, leading to the extinction of the other species.

The team found that extinction occurred faster and more often between the species of  microorganisms that were more closely related. Dr. Jiang says this aspect of the study supports Darwin’s theory, referred to as the phylogenetic limiting similarity hypothesis.

This hypothesis is just one of the many Darwin published in “The Origin of Species.”  It was through this book that Darwin introduced the scientific theory that populations evolve over the course of generations through a process of natural selection.

This weekend on the “Science World” radio program, Dr. Jiang explains this hypothesis and talks to us about his team’s research and what else they learned from their studies.

Listen to the interview here…

[audio://|titles=One On One – Dr. Lin Jiang – Web]

Other stories we cover on the “Science World” radio program this week include: