How does cooperation evolve?
Researchers unravel why organisms frequently help each other

Date:
July 23, 2020
Source:
Max Planck Institute for Chemical Ecology
Summary:
In nature, organisms often support each other in order to gain an
advantage. However, this kind of cooperation appears to contradict
the theory of evolution proposed by Charles Darwin: Why would
organisms invest valuable resources to help others? Instead,
they should rather use them for themselves, in order to win the
evolutionary competition with other species. A new study has now
solved this puzzle.



FULL STORY ==========================================================================
In nature, organisms often support each other in order to gain an
advantage.

However, this kind of cooperation contradicts the theory of evolution
proposed by Charles Darwin: Why would organisms invest valuable resources
to help others? Instead, they should rather use them for themselves,
in order to win the evolutionary competition with other species. A new
study led by Prof. Dr.

Christian Kost from the Department of Ecology at the Osnabrueck University
now solved this puzzle. The results of the study were published in the scientific journal Current Biology. The research project was performed in collaboration with the Max Planck Institute for Chemical Ecology in Jena.


========================================================================== Interactions between two or more organisms, in which all partners involved
gain an advantage, are ubiquitous in nature and have played a key role in
the evolution of life on Earth. For example, root bacteria fix nitrogen
from the atmosphere, thus making it available to plants. In return,
the plant supplies its root bacteria with nutritious sugars. However,
it is nevertheless costly for both interaction partners to support each
other. For example, the provision of sugar requires energy, which is
then not available to the plant anymore.

From this results the risk of cheating interaction partners that consume
the sugar without providing nitrogen in return.

The research team led by Prof. Dr. Christian Kost used bacteria as
a model system to study the evolution of mutual cooperation. At the
beginning of the experiment, two bacterial strains could only grow when
they provided each other with essential amino acids. Over the course
of several generations, however, the initial exchange of metabolic
byproducts developed into a real cooperation: both partners increased
the production of the exchanged amino acids in order to benefit their respective partner. Even though the increased amino acid production
enhanced growth when both partners were present, it was extremely costly
when individual bacterial strains had to grow without their partner.

The observed changes were caused by the fact that individual bacterial
cells had assembled into multicellular clusters. In these cell groups, cooperative mutants were rewarded. The more resources they invested in
the growth of other cells, the more nutrients they received in return
from their partners.

"This kind of feedback represents a previously unknown mechanism, which promotes the evolution of cooperative interactions between two different organisms," says Prof. Dr. Christian Kost, leader of the study. Although
the study was performed with bacteria in a test tube, the mechanism
discovered can most likely explain the evolution of cooperation in many different ecological interactions.


========================================================================== Story Source: Materials provided by
Max_Planck_Institute_for_Chemical_Ecology. Note: Content may be edited
for style and length.


========================================================================== Journal Reference:
1. Daniel Preussger, Samir Giri, Line'a K. Muhsal, Leonardo On~a,
Christian
Kost. Reciprocal Fitness Feedbacks Promote the Evolution
of Mutualistic Cooperation. Current Biology, 2020; DOI:
10.1016/j.cub.2020.06.100 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200723115234.htm

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