MOM...You mean that we came from MONKEYS?

What led to bipedal locomotion? Well, Africa is much different than it is today. The ancestors of "Lucy" or Australopithecus afarensis were most likely tree-dwellers in a more rain forest-like environment. However, Africa started to "dry out" and the rain forests were becoming more grassland. As the environment changed, so did our ancestors. There are many hypotheses on what happened at the forest shrank.

Some of these ideas include:

• Standing up to see over tall grass
• Pick fruit from trees
• Cool more efficiently (less surface area being warmed by the sun)
• Saves energy

As the forest changed, and the area between food patches increased, walking on all fours made it difficult to carry items (like food) and walking on two legs was "inefficient" for long distances, bipedal locomotion was a hell of a benefit.

Thus, walking on two legs saved the organism energy. And that gave our ancestor a competitive advantage. More food, more land coverage and more efficient energy usage is a huge advantage in the game of natural selection.

Now, for the brain size "thing"...I'm going off the reservation for this one. I feel like sharing some ideas that I have read before and some of my own (they are all starting to run together...). I think that our brain size is a direct response to the role of food. The powerful jaw of apes need an anchor point, and that anchor point would have restricted the amount of room that was available for the brain to expand. As diet changes, the need for the extremely strong jaws and different teeth start to disappear. As more protein is available, and the need for stronger jaws decreased, the brain has more room to expand. As food energy increases, more brain activity (which is very energy intense) is available.

I think that food drove evolution. But, I've been wrong before...and will be again. As I continue to read I'm sure that I will find more answers...or more questions. Deep, huh?

Out...

JBlack