Current estimates stand at 25 plant species for the South Atlantic island of South Georgia and 10,000 to 12,000 for Madagascar.
Willdenow did not suggest any explanations of why warmer temperatures led to more diverse plant life. But one of his students, an aristocratic teenager who went on to be one of the greatest scientists of the era, did.
In his old age, Baron Friedrich Heinrich Alexander von Humboldt tried to destroy all records of his childhood, to prevent future biographers uncovering anything unflattering and to prevent any revelations about his personal life obscuring history’s view of his science. No matter: Alexander von Humboldt’s scientific achievements alone are more than enough to chew on. As a biologist he demonstrated the influence of electricity on nerve and muscle tissue and showed how the electric eel has its shocking effect. As a natural historian, he collected 60,000 specimens and described 3,500 new species. As an anthropologist, he was the first European to study the Incan, Aztec, and Mayan civilizations and deciphered the Aztec calendar. As a geologist he was the first to note that volcanoes come in chains and suggested that this had to do with lines of weakness in the earth’s crust. As an oceanographer, despite never sailing on the Pacific, he predicted the existence of that ocean’s Peru Current (sometimes called the Humboldt current) from observations of the South American climate. His friends included Goethe, Thomas Jefferson, and Tsar Nicholas I of Russia. He founded the first international scientific organization, to pool and share data on the study of the earth’s magnetic field. His last work was a book, titled Cosmos, which attempted to describe and unite all scientific knowledge. It was unfinished on his death in 1859, at age 90. The German government gave him a state funeral.
Born into a family of slightly down-at-the-heel Prussian nobility, Humboldt followed his time under Willdenow with study at Göttingen University, then Germany’s leading scientific school. After this he studied geology at the Freiberg School of Mines. In 1792 he took up a job as an inspector in the Prussian Department of Mines. In 1796 his mother died and left him a large fortune. Humboldt could now pursue his greatest ambition—to travel. As a child he had read of Cook’s