Welcome to brain Stuff, a production of I Heart Radio Pay brain Stuff. I'm Lauren volk Baum and this is a classic episode from our former host, Christian Sagar. We usually think of evolution as being a near cosmically slow process, and often it is. After all, living beings in our relationships with our environments can be really complex, with dozens of genes coming together to create the traits that help or hurt our chances of survival. But you don't have to be a germ, or a fruit fly or a
peace shoot to show change quickly. Today's episode is the strange story of a particularly swift lizard evolution. Hey, brain Stuff, it's Christian Sager here. So evolution takes time, but just how much time it takes is the issue. How long, for instance, did it take therapod dinosaurs to evolve into modern birds tens, if not hundreds of millions of years.
But since the turn of the last century, when American biologist Herman Bumpust noticed that individual sparrows in a population became larger as the result of one huge snowstorm, scientists have been observing instances of short bursts of evolutionary progress
over a significantly brief period of time. Definitive instances of rapid evolution are tough to come by, though, even in these days of advanced genetic testing, but a recent study published in the journal Science finds that over the course of just a few months, green annully lizards living in the area of the Mexico Texas border evolved a rapid genetic tolerance to cold weather after an unusually frigid winter. Green Annullies are warm weather reptiles that evolved on the
Caribbean island of Cuba. They found their way to the mainland long ago, but a prolonged and extreme cold snap can really put the hurt on a population of annuls. The winter of did just that before that year's famed polar vortex hit. However, the research team collected annulis in August to find out just how cold one of these lizards could get before its motor function was compromised, specifically, that is, when it couldn't right itself when it was
knocked over. They collected annuals from five different sites across Texas and found that when gradually cooled in a chamber in the lab, the individuals from the southernmost site became uncoordinated at around fifty two degrees fahrenheit or eleven degrees celsius, but the ones collected from the northernmost site became unable to right themselves at around forty three degrees fahrenheit or
six degrees celsius. Because the scientists already had genetic samples from the lizards in the first study, When a few months later temperatures plummeted to lows that hadn't been seen in fifteen years, the researchers went out and collected some of the surviving lizards from all five sites. They placed them in the same cooling chambers and found the southernmost Annullies exhibited much more cold resistance than the ones that
had been collected back in the summer. They could now stand strong in the face of forty three degrees fahrenheit or six degrees celsius. RNA sequencing before and after the cold front also revealed significant differences between individuals from the southern genomic regions before and after the weather event. By the way, did you know that Annulli's living in urban
areas have stickier feet than their country cousins. Apparently it's an evolutionary adaptation to having to cling to class and metal. Now I want to be bitten by a radioactive annually so I can crawl waltz with them. Today's episode was written by Jesselyn Shields and produced by Dylan Fagan, Little Berlante, and Tyler Clang. For more on lit and lots of other topics, visit how stuff works dot com. Brain Stuff
is a production of I Heart Radio. For more podcasts my heart Radio, visit the iHeart Radio app, Apple Podcasts, or wherever you listen to your favorite shows.