Why are Old World and New World vultures considered a classic example of convergent evolution?

They independently adopted similar lifestyles and traits due to selective pressures

Convergent evolution occurs when unrelated organisms independently develop similar characteristics as they adapt to similar environmental challenges or ecological niches. In the case of these two vulture groups, they do not share a recent common ancestor despite their shared habit of eating carrion and having bald heads. Instead, the selective pressures of scavenging in different parts of the world drove them to evolve the same survival strategies separately over millions of years, leading to the development of superficially similar physical features.