The traditional view of human evolution holds that at some point our ancient ancestors moved out of the forest and onto the dry savannah. This change of scenery forced the emergence of an upright gait, encouraged tool use, and required a larger brain, all of which eventually lead to language and culture and global domination (bwahaha!). However, Dr. Rick Potts argues that it was our ancestor’s ability to adapt to a rapidly changing environment that lead to their success and, ultimately, us. In a very interesting article (you can read the whole thing here) Dr. Potts explains his theory of variable selection and why the common view of human decent is incorrect.
One important distinction that he makes is that human evolution (and evolution of all organisms) happens occurs not like a ladder but more like a tree. At any given time, many closely related species may be living together. In our case, we happen to be the last living species left on our part of the tree of life. Amazingly, as recently as 200,000 years ago there may have been 4 species of humanoids living on Earth! (Check out this page for more info and a really cool diagram of human evolution.) Dr. Potts research is trying to determine what made us Homo sapiens better at surviving than our hominid relatives. His theory that we were simply better able to adapt to a changing world has very important implications for the world of today. As the Earth changes, will we be able to adapt and survive?