Direct proof for Darwin’s hypothesis on competition between species
It was Darwin who first proposed that the struggle for existence would
be more fierce between closely related species as compared to
comparatively distant ones. And although this was generally accepted as a
premise, the following study (Source 3) contains the strongest direct
experimental evidence yet to support its validity.
Li
n
Jiang (adjacent picture), School of Biology at Georgia Tech, Cyrille
Violle, Georgia Tech biology graduate student Zhichao Pu, and Diana
Nemergut, from the Institute of Arctic and Alpine Research and the
Environmental Studies Program at the University of Colorado at Boulder
are responsible for the discovery.
For the study, the
researchers selected bacterivorous ciliated protist microorganisms due
to their rapid rate of reproduction that allowed them to study the
results over many generations. The researchers set up 165 microcosms
that contained either an individual protist species or a pairing of two
species, along with food for them to compete for. They collected weekly
samples from each microcosm, recording the presence or absence or
density of species, and they did this for 10 weeks.
At the end,
the results showed that all species survived until the end of the
experiment when they were alone in a microcosm. However, in more than
half of the experiments in which protists were paired together with
other species, one of the two species dominated, leading to the
extinction of the other species.
Also, the frequency and speed of
this extinction process , called competitive exclusion, was
significantly greater between species that were more closely related.
The study also showed that the frequency of competitive exclusion was
significantly greater between species that had similar mouth sizes.
“This study is one step toward a better understanding of how
phylogenetic relatedness influences species interactions,” said Jiang.
“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.” (Source 1)
Source:
1) http://www.newswise.com/
2) http://www.eurekalert.org/
3) Published: http://
4) http://www.examiner.com/
Image: Lin Jiang displays a microscopic image of a protist species used
in the experimental microcosms. Credit: Georgia Tech/Gary Meek
Direct proof for Darwin’s hypothesis on competition between species
It was Darwin who first proposed that the struggle for existence would be more fierce between closely related species as compared to comparatively distant ones. And although this was generally accepted as a premise, the following study (Source 3) contains the strongest direct experimental evidence yet to support its validity.
Li
It was Darwin who first proposed that the struggle for existence would be more fierce between closely related species as compared to comparatively distant ones. And although this was generally accepted as a premise, the following study (Source 3) contains the strongest direct experimental evidence yet to support its validity.
Li
n
Jiang (adjacent picture), School of Biology at Georgia Tech, Cyrille
Violle, Georgia Tech biology graduate student Zhichao Pu, and Diana
Nemergut, from the Institute of Arctic and Alpine Research and the
Environmental Studies Program at the University of Colorado at Boulder
are responsible for the discovery.
For the study, the researchers selected bacterivorous ciliated protist microorganisms due to their rapid rate of reproduction that allowed them to study the results over many generations. The researchers set up 165 microcosms that contained either an individual protist species or a pairing of two species, along with food for them to compete for. They collected weekly samples from each microcosm, recording the presence or absence or density of species, and they did this for 10 weeks.
At the end, the results showed that all species survived until the end of the experiment when they were alone in a microcosm. However, in more than half of the experiments in which protists were paired together with other species, one of the two species dominated, leading to the extinction of the other species.
Also, the frequency and speed of this extinction process , called competitive exclusion, was significantly greater between species that were more closely related.
The study also showed that the frequency of competitive exclusion was significantly greater between species that had similar mouth sizes.
“This study is one step toward a better understanding of how phylogenetic relatedness influences species interactions,” said Jiang. “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.” (Source 1)
Source:
1) http://www.newswise.com/
2) http://www.eurekalert.org/
3) Published: http://
4) http://www.examiner.com/
Image: Lin Jiang displays a microscopic image of a protist species used in the experimental microcosms. Credit: Georgia Tech/Gary Meek
For the study, the researchers selected bacterivorous ciliated protist microorganisms due to their rapid rate of reproduction that allowed them to study the results over many generations. The researchers set up 165 microcosms that contained either an individual protist species or a pairing of two species, along with food for them to compete for. They collected weekly samples from each microcosm, recording the presence or absence or density of species, and they did this for 10 weeks.
At the end, the results showed that all species survived until the end of the experiment when they were alone in a microcosm. However, in more than half of the experiments in which protists were paired together with other species, one of the two species dominated, leading to the extinction of the other species.
Also, the frequency and speed of this extinction process , called competitive exclusion, was significantly greater between species that were more closely related.
The study also showed that the frequency of competitive exclusion was significantly greater between species that had similar mouth sizes.
“This study is one step toward a better understanding of how phylogenetic relatedness influences species interactions,” said Jiang. “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.” (Source 1)
Source:
1) http://www.newswise.com/
2) http://www.eurekalert.org/
3) Published: http://
4) http://www.examiner.com/
Image: Lin Jiang displays a microscopic image of a protist species used in the experimental microcosms. Credit: Georgia Tech/Gary Meek
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