snowcat. 2006 Dec 17. Carroll 10-11. <http://development.pharyngula.org/carroll_10_11/>. Accessed 2008 Aug 29.

Posted on M00o93H7pQ09L8X1t49cHY01Z5j4TT91fGfr on Sunday, December 17, 2006

Carroll 10-11

In chapter 10 Carroll discusses the evolution of humans. Some of the important features we have evolved are bipedalism, our larger brain, speech, and language. In order for us to evolve bipedal locomotion changes had to be made in the vertebral column, pelvis, feet and limb proportions, not one simple change could allow for bipedalism. An important discovery in Tanzania was of two sets of footprints that showed two of our ancestors walking upright. An interesting point about our Neanderthal relatives is that they had a larger brain than us, and for some unexplained reason we survived and they died out. One of the important factors in the evolution of the brain seems to be the neocortex which is much larger in primates than in other mammals. New centers have also evolved, for example in primates there is a region called the ventral premotor area and this is turned on during visually guided movements. Another important region of the brain is Broca’s area which is found in human brains and is important in speech and language. One anatomical feature of Broca’s area is that it is larger on the left hemisphere of the brain; evidence of this asymmetry has also been found in great apes which suggests that the common ancestor of humans and great apes had this asymmetry.

Carroll begins chapter eleven by talking about how Darwin chose to word the concluding paragraph of Origin of the Species and how the words he chose for this book “endless forms most beautiful” remain unchanged throughout the book. Carroll states that Evo Devo is a cornerstone for a more modern synthesis. Many different types of animal forms are created using the same basic toolkit. Also many different organs and structures in various animals use the basic genetic components controlling their formation. He also states how switches are very important in creating large amounts of complexity and diversity. He credits microevolution as the vehicle for macroevolution stating the continuity of the tool kit and structures in many organisms throughout time as evidence. Then Carroll discusses how evolution is much more of a controversy in the US then other countries and how many Americans are clueless about even the most basic principles of biology. He concludes his book by talking about human settlement has often led to the demise of several species of animals. From Van Diemen’s land tiger and the Tasmanian wolf to the dodos of Mauritius human settlement has often decreased the diversity of animals. Carroll concludes by asking if we will do something to stop the loss of diversity.