The Evolution of the Human Brain :: Biology Essays Research Papers

The Evolution of the Human Brain Although my previous two papers concerned the interplay between neurobiology and genetics, I have not quite worked the issue out to my satisfaction nor to the depth which I think the topic warrants. Therefore, I will again tackle this complex set of biological questions pertaining to the ways in which our genes shape our brains. My first paper dealt with the nature-nurture debate and its relation to the brain-behavior problem raised in class. Then, in the second paper, I moved on to a narrower issue in neurogenetics; I wrote about Fragile X Syndrome and the ways in which a specific genetic mutation can drastically change behavioral output. I would now like to enlarge the scope of this outlook on genes and the brain to encompass the topic of the evolution of the human brain. Throughout the semester, as we covered sensory input and motor output, a single neuron and complex motor symphonies, car sickness and dreaming, I have left class wondering: how are these behaviors, from the micro- actions of a neuron to the macro-actions of a human being, adaptive? How did large brains and extensive nervous systems come to be selected for? And why have humans, alone, acquired them? Some aspects of these questions seem to reside in the realm of the paleontologists, others, in the realm of the neurogeneticists. They do, however, seem to me to be central to neurobiology. For it is drilled into us that form connotes function, and, perhaps, if we come to understand how and why the human nervous system was formed, we will have a richer understanding of how and why it functions as it does. The work and thoughts of Richard Dawkins, author of The Selfish Gene, have been useful to me in working out the issues of my previous papers, and I will again employ his theory that people are merely survival machines for the genes they carry. This is, I think, a logical argument with which to begin a discussion of the evolution of the brain, as it reduces evolutionary processes down to the bare bones of living things, that essential material: human genes and the DNA comprising them. This viewpoint excludes the complicated semi-philosophical questions pertaining to consciousness, higher thought, and the Self experienced by human beings via their neural processing; it primarily addresses the usefulness to human beings of the inordinately large organ contained within the skull.