<P> There has been a gradual increase in brain volume as humans progressed along the timeline of evolution (see Homininae), starting from about 600 cm in Homo habilis up to 1500 cm in Homo neanderthalensis . Thus, in general there's a correlation between brain volume and intelligence . However, modern Homo sapiens have a brain volume slightly smaller (1250 cm) than neanderthals, and the Flores hominids (Homo floresiensis), nicknamed hobbits, had a cranial capacity of about 380 cm (considered small for a chimpanzee) about a third of that of H. erectus . It is proposed that they evolved from H. erectus as a case of insular dwarfism . With their three times smaller brain the Flores hominids apparently used fire and made tools as sophisticated as those of their ancestor H. erectus . In this case, it seems that for intelligence, the structure of the brain is more important than its volume . </P> <P> By 2.4 million years ago Homo habilis had appeared in East Africa: the first known human species, and the first known to make stone tools, yet the disputed findings of signs of tool use from even earlier age and from the vicinity as multiple Australopithecus fossils may put this to question its "greater intelligence when compared to earlier and more primitive Australopithecus genus". </P> <P> The use of tools conferred a crucial evolutionary advantage, and required a larger and more sophisticated brain to co-ordinate the fine hand movements required for this task . Our knowledge of the complexity of behaviour of Homo habilis is not limited to stone culture, they also had habitual therapic use of toothpicks . The evolution of a larger brain created a problem for early humans, however . A larger brain requires a larger skull, and thus requires the female to have a wider birth canal for the newborn's larger skull to pass through . But if the female's birth canal grew too wide, her pelvis would be so wide that she would lose the ability to run, which was a necessary skill 2 million years ago . </P> <P> The solution to this was to give birth at an early stage of fetal development, before the skull grew too large to pass through the birth canal . This adaptation enabled the human brain to continue to grow, but it imposed a new discipline . The need to care for helpless infants for long periods of time forced humans to become less mobile . Human bands increasingly stayed in one place for long periods, so that females could care for infants, while males hunted food and fought with other bands that competed for food sources . As a result, humans became even more dependent on tool - making to compete with other animals and other humans, and relied less on body size and strength . </P>

Who was the first person to start thinking of heredity in a modern way