ITRealms:
"Darwin’s evolutionary theory predicts survival of the fittest. So why do different survival tactics co-exist, if evolution should always favour the winning strategy?"
To
answer that question scientists at the Universities of Bath and
Manchester have been studying a single-celled amoeba, also known
as slime mould, which displays certain behaviours that have been
labelled as “cheating”
or “cooperating”.
In
a study, published in the prestigious journal Current
Biology,
the team found that cheaters don’t necessarily win in terms of
overall survival, suggesting that biologists should re-evaluate
how they define and measure social cooperation.
ITRealms gathered from the Public Relations Officer at University of Bath, Dr. Vicky Just, that their
research
has medical implications when it comes to developing therapies
that use socially successful bacteria to fight diseases such as
lung infections.
Professor
Chris
Thompson from Manchester’s Faculty of Life Sciences explains:
“If the cheats always win, then according to Darwin, altruism
shouldn’t exist. To study this we looked at why the single
fittest strategy in the amoeba community doesn’t dominate.”
The
team looked at how amoebae compete against each other during
cooperative encounters. These strange microbes generally live in
the soil as single cells, eating bacteria, but when food is
limited, they clump together to form a ‘slug’ that moves to a
different location before transforming into a fruiting body
which eventually releases spores to produce the next generation
of amoebae.
Development
into
a fruiting body requires cooperation, with some of the amoebae
forming the stalk part of the fruiting body, effectively
sacrificing themselves for the benefit of the ones that become
spores. Therefore biologists have labelled the individuals that
become the stalk as ‘altruists’, with the individuals that tend
to form lots of spores being identified as ‘cheats’ because they
benefit disproportionately.
However,
the scientists from Bath and Manchester found that these
assumptions don’t necessarily tell the whole story. Those
labelled as cheats don’t end up having higher success than those
that appear to lose since the cheats pay a price for their
apparent success by producing larger numbers of lower quality
spores. These inferior spores have lower survival rates, so
overall the number of spores that survive is similar to those
amoebae who ‘cooperate’.
According to Professor
Jason
Wolf from the University of Bath’s Department of Biology &
Biochemistry, their study showed that there are definitely winners and losers in social coorporation.
“Our study shows that whilst there are
definitely winners and losers in social
cooperation, you can’t
measure social success just by counting the number of spores
these moulds produce. Those that produce lots of spores often
make inferior ones that don’t have any overall advantage over
their competitors," he said.
Stressing that scientists require to take a second look at the bigger picture when measuring social
success, rather than making assumptions based on measuring the
wrong things.
For Professor
Chris
Thompson what the study says was that when scientists look at
systems through just one aspect then that system could appear to
be unbalanced and shouldn’t work, but in reality they are a
collection of many features that together determine success,
and so variety helps to make man more equal.
“Our study threw up quite a big surprise because the way we measure fitness in a system is currently misleading. By focussing on the number of offspring (in this case spores) rather than the quality, we’re using an incorrect measurement of success. “What we thought of as socially successful needs to be re-evaluated,” Thompson said.
+Remmy Nweke (ITRealms)
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