We wanted kids, and now we want to travel. Pretty much everyone instinctively feels the need to do the former (and many of us obey that instinct), but only for some is the urge to travel strongly felt. When I heard guests on the recent RTE Radio1 conversation with two travelling mothers, I felt part of their tribe. I wonder whether the travel bug can be explained in Darwinian terms.
(I know that most people venture beyond their own borders these days, but there are differences between wanting to get out from underneath grey Irish skies for two weeks a year, and wanting to really see other parts of the world. Those with the latter in mind are most definitely in the minority. But as a sidebar, it's quite interesting to see that from an evolutionary point of view, despite the amount of time we've populated the northern latitudes, we've never taken to the cold and darkness.)
The problem is that while it might make sense for a population to support a bunch of curious explorers (who will find new resources and lands to cope with increasing populations), most evolutionary biologists don't believe that natural selection operates on groups - just individuals. And curiosity kills more than the cat: In theory, natural selection should have operated against these risk-takers.
But nonetheless the urge is there, and the reasons have got to be, in base, Darwinian. So here's my layman's take on how natural selection, operating on the individual, could create pressure in favour of exploration:
If a tribe is running out of resources and doomed to die out, the explorers are the ones who are most likely to survive by moving on and finding a new base that is likely to support the hunter-gatherer requirements. If they explore as a group of mixed sex, and establish a new settlement, then the genes for exploration are going to form the basis of the entire future tribe's genotype. In other words it'll have such a strong foothold in the population that even allowing for evolutionary pressure against exploration (curiosity killing the cat) it will survive in some percentage in the population. At least it will survive long enough so that when that new tribe finds that resources are running out, the remaining explorers in the population will be the ones to venture out and establish a new population. So to summarize, new populations were more likely to be spawned by adventurers.
If any of this is true, it's interesting to think about what the current state of affairs might be. There is no longer any hunter-gather activity, or spawning of new populations but then again exploration and travel is less likely to kill you. At least - I hope so!!?