Evolution Can Happen in as Few as Eight Years, You're Just Lazy

One of the greatest arguments against evolution was (and is, to an extent), if evolution is so prevalent, why can’t we see it?  I mean, how come as time passes, rather than becoming fitter specimens, we just become drunker, saggier, and slower to guess the Wheel of Fortune puzzles?

Well, scientists have recently discovered that I don’t know what’s wrong with you, but you’re obviously doing it wrong.  Because guppies, simple little fishsticks of the sea, are able to evolve in less than a decade…  

Here’s how the experiment worked: one set of guppies was placed upriver in Trinidad’s Yarra River, where dams protected them from predators.  Another got stuck on the wrong side of the tracks, where bigger fish liked to get their snack on.

Eight years later (less than 30 guppy generations), the researchers found that the guppies in the low-predation environment above the barrier waterfall had adapted to their new environment by producing larger and fewer offspring with each reproductive cycle. No such adaptation was seen in the guppies that colonized the high-predation environment below the barrier waterfall.

The paradise city guppies only had to worry about beating each other to the algae buffet line, so they adapted to produce larger offspring.  Because there was no threat to their survival, they could birth fewer of them as well.  But when the both sets of guppies were placed in a completely foreign river environment…

[Researchers] found that the resident, locally adapted guppies [from the new river] were significantly more likely to survive a four-week time period than the guppies from the two sites on the Yarra River. This was especially true for juveniles. The adapted population of juveniles showed a 54-59 percent increase in survival rate compared to their counterparts from the newly introduced group.

Put another way: it’s not evolution’s fault that you got fat.

Source: UC Riverside.