Anaximander
lived 546 BCE
Said the Earth is round (and 300 years later, Aristarchos successfully calculated its circumference). Rejected Thales' idea that the "ur-substance" was water because "everything would have converged into water".
Had an idea of evolution, that humans must have come from fish or some such (correct!). 2200 years later, characters such as Jean-Baptiste Lamarck and Charles Darwin fleshed it out, though they may not have known of Anaximander.
Said to be the first person to draw a map (let that sink in for a moment). I doubt it's literally true, but imagine having invented maps. Next time you open the map on your phone, take a moment to thank Anaximander.
Liked practical research, unlike the later Greeks.
His student Anaximenes, who said the earth was a disk, was liked more during antiquity.