Prosanta Chakrabarty is an evolutionary biologist and ichthyologist who discovers new species and examines the biology of the species in order to better understand the history of the world.
In a recent TED talk, Chakrabarty explains how he has been focusing on caves to look for new species. More specifically, Chakrabarty has been studying cavefish. Cavefish hold clues about the biology and geology of the past. The location of a cavefish gives information on how land masses have moved and changed. Their genes and bodies give information on the evolution of sight.
Fish adapting to a cold dark cave environment lose their eyesight over many generations. Yet, they don't all lose their sight in the same way. In fact, every cavefish species has evolved in a slightly different way; thus, giving unique historical information.
Sources: TED