Describe darwin's observations on the galapagos islands during his voyage on the hms beagle

Charles Darwin’s five-year voyage in the early 1830s on H.M.S. Beagle has become legendary, as insights gained by the bright young scientist on his trip to exotic places greatly influenced his masterwork, the book On the Origin of Species.

Darwin didn’t actually formulate his theory of evolution while sailing around the world aboard the Royal Navy ship. But the exotic plants and animals he encountered challenged his thinking and led him to consider scientific evidence in new ways.

After returning to England from his five years at sea, Darwin began writing a multi-volume book on what he had seen. His writings on the Beagle voyage concluded in 1843, a full decade and a half before the publication of On the Origin of Species.

why do the isotopes of a particular element behave differently in nuclear reactions but the same in chemical reactions? chemical reactions involve changes to electrons in an atom; isotopes do not differ in electrons, and so they react the same way during chemical changes.