When we learn about evolution in school, it feels old and slow. (Charles Darwin’s impressive beard later in life probably doesn’t help here.)
But evolution is very much still happening today – and it’s happening to us.
Right here, right now.
It’s too soon to say what humans will look like a few thousand years from now, but here are some of the most recent quirks – and even superpowers – we’ve acquired thanks to the power of selection.
- 1. Drinking milk as adults
Drinking milk is one of the defining traits of mammals, but humans are the only species on Earth to digest it after infancy, though even now, more than 75% of the world’s population is still lactose intolerant.
After weaning, all other mammals, and most humans, cease producing lactase, the enzyme necessary to break down lactose, milk sugar.
But a mutation that appeared on the plains of Hungary about 7,500 years ago allowed some humans to digest milk into adulthood. We probably started with cheeses – cheddar and feta contain less lactose than fresh milk and softer cheeses, and Parmesan contains almost no lactose.
This may seem nutritionally inconsequential (though delicious) now, but the ability to digest incredibly calorie-dense dairy products was incredibly useful for humans surviving the cold winters of Europe.
- 2. Disease resistance
Evolution is about the survival of the fittest – and a big part of evolutionary fitness is not dying from a disease before you’ve had children. So it makes sense that evolution would be giving us a boost against some common diseases.
The most-studied disease we’ve been outrunning lately is malaria. If you’ve taken an introductory biology course lately, you may remember a strange connection with sickle-cell anemia. That’s because there’s a specific gene that, if you have one copy, will protect your red blood cells from invasion by the malaria parasite – but two copies will distort red blood cells and block their passage through blood vessels.