Key sources on the “Judyth” storyinclude:
– and aresponse to critics written in November2003.
Did the larger brain lead to the behaviors, or did the behaviors lead to the larger brain? If other evolutionary trends have relevance, they mutually reinforced each other and provided positive feedbacks; down one evolutionary line it reached conditions that led to the human brain. The initial behavior was probably the use of a body part (the brain) for a new purpose, and its success led to selective advantages that led to mutual reinforcement. Although it is by no means an unorthodox understanding, I think that the likely chain of events was walking upright freed hands for new behaviors, which led to new ways of making and using tools, which enhanced food acquisition activities. This allowed the energy-demanding brain to expand, as well as related biological changes, which led to more complex tools and behaviors that acquired and even more energy. That, in short, defines the human journey to this day, which the rest of this essay will explore. There has never been and probably never will again be an energy-devouring animal like humanity on Earth, unless it is a human-line descendant.
– An The narration is in Dutch, but Judyth speaks in English.
Intelligence can confer great advantages, and the is an early indicator of its benefits. For instance, about twice the size of , which is thought to be due to their larger societies (about twice as large), and the fact that their diet is more than 70% fruit, while the howler monkey’s diet is less than half fruit, and leaves provide twice the proportion of the howler’s diet over the spider’s. Remembering where and when fruit is ripe, and navigating more complex social environments, takes greater thinking power. Just as with howler and spider monkeys, chimpanzees have to range far to find fruit, which is their staple, while gorillas can more readily eat nearby leaves, and chimps have more complex social lives than gorillas do. Chimpanzees also have proportionally larger brains than gorillas' and are considered more intelligent.