Our future may be uncertain, but leading geneticist Steve Jones at the University of College London says he knows one thing for sure: we're not going to change much on the evolutionary ladder. That's because human evolution is coming to a standstill, he claims. Jones says that the three main drivers behind evolution—natural selection, genetic mutation and randomness—don't hold as much anymore in the survival of the fittest race.
Reproductive patterns, for instance, have changed considerably over time and have resulted in fewer older fathers in the West. This has had an effect on evolution, says Jones, because fathers who have children when older than 35 have a higher rate of genetic mutations to pass down the line. A 29-year-old father—the mean age of reproduction in the West—has approximately 300 divisions between the sperm that made him and what he passes on, while a 50-year-old father has well over a thousand divisions.
Weakening natural selection and decreased randomness are other factors that have slowed the process of human evolution. In the past, Jones explains, only children with genetic mutations that made them fitter lived past the age of 20. But now those genetic mutations don't matter as much because better living conditions, especially in the West, have given way to higher rates of survival and longer life spans, reducing natural selection. As the world becomes increasingly connected, humans are not as likely to lose genes either (in small populations change happens more randomly as genes get lost). In fact, Jones argues, humans are 10,000 more common than they ought to be as a result. Whether people want to believe that is a whole other matter.
Via Times Online
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