Alice travels through the mirror in the 2nd part of her journey to the country of the Wonderland where she found the Red Queen. They begin to run until Alice realised that however much they run they are still in the same spot. She asked the Queen: 'What's happening?' and the Queen replied: 'In this country you have to run all you can to remain in the same place. To leave here you have to run double.' This is the evolution of the species.
As living beings, we live with others that sometimes harm us or may even put our life in danger. We call this infection. The organisms react, seeking out the best ways to defend themselves, but the pathogens develop and progress to overcome them. It's a race with the objective, as the Red Queen says, all the effort and changing is for being in the same spot. In an article published in 'Science', it explains an interesting experiment regarding this aspect. Conclusion: What permits the organisms to continue in the race is sex.
The experiment is done with some worms that can reproduce themselves in the sexual way, or even fertilise themselves. They have maintain the population of animals for more than 30 generations with the constant presence of bacteria. The data shows that the populations in which there are male and females they would adapt to the presence of bacteria and survive. On the contrary, the hermaphrodites are more vulnerable and the population diminishes.
This study, of the University of Indiana in the US, tells us that the presence of pathogens is a force of the evolution and confirms the hypothesis of the Red Queen: one has to gradually change in the gene pool to survive. It also tells us that the cost which implicates for the organisms to have both sexes, is what adapts to the changing conditions of the environment.
One can thus conclude, that the variations which introduces sexual reproduction are essential for animals and plants changing, at least, to be in the same place as always.
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