And when you take something like the changing colour of autumn leaves and start to ask why, you’re starting off on an intellectual journey which will take you beyond that moment of visual satisfaction, while robbing nothing from that experience.

Autumn is much redder in North America and east Asia than it is in northern Europe, and this can’t be explained by temperature differences alone. These areas also have a greater proportion of ancient tree lineages surviving: trees have gone extinct at a higher rate in Europe compared with those other areas.

Evolutionary biologists have long pondered the phenomenon of the changing colours of autumn leaves. It’s possible that the red pigments are manufactured in the leaf as a side-effect of something else that’s happening at this time.

Alice Roberts Quotes