3 – A Hairy Situation
Have you ever wondered why, compared to our mammalian cousins, we’re relatively hairless? So have evolutionary biologists, who have wondered why this camouflage-boosting, heat insulating fur has disappeared in humanity.
The leading suggestion is that losing our hair allowed us to cool down faster, freeing us up to hunt, forage, and run about in the blazing heat – something that clearly went hand-in-hand with our ability to walk upright. This has been contested, and other ideas do exist, but it’s the frontrunner for now.
4 – Coping (Or Not) With Higher Altitudes
Although this is something you experience rather than see, it's still a remarkable example of evolution everyone can relate to.
If you’ve ever tried to climb a sizable mountain, you may have – at rest – noticed you’re still curiously short of breath, perhaps even faint. That’s because at higher altitudes, the density of air is lower, which means there are fewer oxygen molecules per breath.
Most of us will struggle somewhat in those conditions, but certain people around the world don’t. Sherpas, for example, are far more proficient higher up, but why? A recent study found that it’s because their mitochondria – the powerhouses of our cells – use oxygen more efficiently to produce ATP, which transports chemical energy to and fro.
The reason they possess this ability is because they’ve lived at high altitudes on the Tibetan Plateau for 30,000 years, and their genomes have been altered in response to that.