In A Nutshell
High up in the Andes Mountains sit grasslands that researchers have nicknamed sky-islands. These sky-islands have been found to be home to not only thousands of different species of plants, but species of plants so different that they’ve realized it’s one of the fastest-evolving places on Earth. In only the roughly 2.7 million years since the Andes have reached their current elevation, nearly 4,000 different types of plants have evolved to survive in the brutal mountain climate.
The Whole Bushel
We usually think of the idea of evolution as one that slowly unfolds over generations and generations. We think of evolution changing life-forms ever so slowly, in a way that it takes millions and millions of years to give zebras their stripes or fish the ability to swim deeper and glow in the dark. But researchers have found one place on Earth where evolution is happening at a relatively blinding place—high up in the Andes mountains.
The paramo is an area that’s essentially a grassland environment that forms at a very high altitude, somewhere between 3,000 and 4,500 meters (10,000 and 15,000 ft) above sea level. They don’t just occur in the Andes, but the one in the Andes is pretty unique. It’s only been around for around 2.7 million years, and in that time, it’s managed to breed a simply staggering amount of life.
Given the nickname sky-islands, the paramo ecosystem of the Andes Mountains is home to nearly 4,000 different types of plants—making it one of the most diverse in the world. About 60 percent of the species are native to the area, while others have been created from the relatively recent introduction of other species from North America, the Amazon rain forest, and other areas throughout South America.
Measuring how fast the plants and animals of an area are evolving is a tricky thing, and it requires a bit of detective work. Researchers from universities all over the world are looking at the paramos of the Andes in an attempt to track just how fast the species there are evolving.
The most famous example of evolution in motion is Darwin and his finches. The 13 different types of finches in the Galapagos Islands all evolved from one common ancestor, and by looking at just how long the island chain has existed gives a pretty good idea of how long it took each one of the species of birds to evolve.
Researchers are doing the same thing with the plants of the Andes grasslands. By taking plants belonging to the different evolutionary branches of the same family, they’re able to trace backward to see how long it’s taken the different types of plants to evolve. And they’ve found it’s an evolutionary hot spot, with evolution still very much in ultra-fast progress.
Part of the reason plants and animals are forced to evolve at a rate much higher in these areas than in other spots on Earth is the rather strange surroundings they need to deal with. It’s extremely cold but extremely sunny. There are also relentless ultraviolet rays, strong winds, cloudy cover, and the altitude. In order to survive, they not only had to come up with some pretty ingenious survival mechanisms, but they had to do it relatively quickly.
Quickly (at least, in the grand scheme of things), with only a few million years having passed since the climate in the Andes became representative of what it is today. That rapid change in elevation and climate forced the endemic plant life to either do the same or die.
Show Me The Proof
National Institutes of Health: Paramo is the world’s fastest evolving and coolest biodiversity hotspot
PLOS One: Adaptation and Convergent Evolution within the Jamesonia-Eriosorus Complex in High-Elevation Biodiverse Andean Hotspots
Beacon: The paramos—understanding a hyperdiverse ecosystem one genus at a time
NY Times: Fast-Paced Evolution in the Andes