Modern man, subject to natural selection

2012/06/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Eboluzioa

Is modern man still subject to natural selection? Or has it escaped through culture and technology? A paper published in PNAS magazine in May has given favorable evidence to the first. In this work, a team led by researchers from the University of Sheffield has analyzed the experiences of 5,923 people born in Finland between 1760 and 1849 to see if the evolution of these groups conforms to the characteristics of populations subjected to natural selection. And the answer is yes.

Specifically, the main screens of natural and sexual selection have been crossed with the data collected in the registries: survival, procreation, reproductive success and fertility (number of reproductive descendants) until the fertile age. For tax reasons, the then Finnish church collected in detail all births, deaths and marriages, and researchers have been able to fully monitor the genealogy. Being monogamous populations, who seriously thought not to act like this, researchers have been able to take weddings as an indicator of procreation.

The results of the crossing show that the variability measured in the four parameters coincides with the usual of populations suffering from natural selection. And despite the monogamous populations, the predictions of the theory of sexual selection were fulfilled: the most severe sex (in this case, men) presented a greater variability in success and reproductive success, and a greater link between the two previous parameters.

According to the researchers, the measurement of this type of results in monogamous populations living from agriculture and fishing is wrong if it is considered that the influence of natural selection had long been eliminated. "Successive monogamy and agriculture would limit selection options, but analysis shows that it still has enough space to act," they said. In fact, the development of agriculture has been considered as man's first blow to natural selection. And then, technological and medical development since the industrial revolution.