When and why individual organisms work together at the game of life, and what keeps cheaters in check.
Evolution by natural selection, Darwin wrote, mainly depends on “success in leaving progeny.”1 He also recognized that such success may be achieved by “dependence of one being on another.” When are individuals most successful living on their own, and when can they benefit from working with others?
It’s not always an easy question to answer. For parasites living in or on other organisms, for example, maximizing reproduction is a tricky proposition. Using more host resources lets parasites produce more offspring, but overexploitation shortens host life span, reducing the amount of time the parasites have to reproduce. So it may make sense for parasites to avoid harming their hosts, and parasites that increase host life span may fare even better. As British evolutionary biologist and geneticist John Maynard Smithnoted more than 100 years after Darwin’s musings on reproduction and cooperation, you shouldn’t kill the goose that lays the golden eggs.2
But Maynard Smith recognized that this strategy is based on a critical assumption: that if you do not kill the golden goose, no one else will either. In other words, limiting host exploitation will only benefit a parasite if the host isn’t also inhabited by other, more virulent strains or species. If another parasite is using so many resources that it kills the host anyway, why should any organisms on the same host limit their own reproduction by using fewer host resources? This “tragedy of the commons” type of dilemma, in which individuals benefit from activities that undermine shared benefits, is a major reason why cooperation is not universal.
Sourced through Scoop.it from: www.the-scientist.com
A cooperação entre espécies pode ser um factor por vezes determinante para benefício de algumas dessas espécies, mas também poderá dar azo a que algumas espécies oportunistas tomem conta do negócio.