Solitary hotel in mountain pass. Autumn. Twilight. Fire lit. In dark corner young man seated.
When humans evolved bigger brains, we became the smartest animal alive and were able to colonise the entire planet. But for our minds to expand, a new theory goes, our cells had to become less willing to commit suicide – and that may have made us more prone to cancer.
When cells become damaged or just aren’t needed, they self-destruct in a process called apoptosis. In developing organisms, apoptosis is just as important as cell growth for generating organs and appendages – it helps “prune” structures to their final form.
By getting rid of malfunctioning cells, apoptosis also prevents cells from growing into tumours. […]
McDonald suggests that humans’ reduced capacity for apoptosis could help explain why our brains are so much bigger, relative to body size, than those of chimpanzees and other animals. When a baby animal starts developing, it quickly grows a great many neurons, and then trims some of them back. Beyond a certain point, no new brain cells are created.
Human fetuses may prune less than other animals, allowing their brains to swell.
