Context: Explorers and naturalists have been asking this question for centuries. Many have also been curious as to why some areas are more biodiverse than others.
oOne of them was Alexander von Humboldt (1769-1859) – a polymath who recorded observations on various natural phenomena across the fields known today as geography, geology, meteorology, and biology.
Humboldt’s enigma
oEx: Mountains, like the eastern Himalayas.
oFirst: geological processes, like uplifts, result in new habitats where new species arise, so the habitats are ‘cradles’.
oSecond: species on some climatologically stable mountains persist there for a long time, so these spots are ‘museums’ that accumulate many such species over time.
oThe Western Ghats plus Sri Lanka biodiversity hotspot lies within this zone, showcasing high biodiversity.
oOld lineages persist on mountaintops, showcasing the impact of stable climates and fluctuating habitats in lower elevations.