Chapter 2: Biology and Human Potential
Evolution: Adaptation through Natural Selection
Mostly Nature
As we move along in the book, I will frequently try to relate the current material to major themes described in Chapter 1. I will ask you to periodically recall Maslow’s pyramid of human needs, the video of the Nukak tribe in the rainforest, and the transformation of New York City over the course of two centuries. Despite the inventions and technological innovations of the relatively recent past, there are still people living the nomadic Stone-Age lifestyle which characterized the human condition for almost our entire time on this planet. What made it possible and what was necessary in order for this transformation to occur?
We share many basic needs and behavior with other species. We all inhabit a planet replete with edible foods, predators, and potential sexual partners. Unless we continue to eat adequately, successfully avoid and/or escape from predators, and mate, we will not survive as individuals or as a species. In order to eat, survive, and reproduce, we need to be able to sense food and danger, identify receptive mates, and respond in an adaptive manner.
The Mostly Nature section addresses how our physical structure impacts upon our ability to survive and realize our potential as individuals and a species. In Chapter 1, we reviewed how our contemporary approach to psychology integrated the interests and goals of the early schools. This will be reflected in the chapters which comprise this section of the book. The earliest school, eventually named structuralism, was primarily concerned with our internal world consisting of sensations, images, and feelings. In Chapter 3, we will review the structure and function of our sense organs for external stimuli (e.g., our eyes for vision, ear for hearing, etc.) addressing how experience results in combining stimulus elements into meaningful patterns (i.e., gestalts). The functionalist school was concerned with how our internal world enabled us to adapt to our external world. Chapter 4 reviews how we process and eventually respond to internal stimuli (e.g., hunger for food deprivation, thirst for water deprivation, pain, etc.).
The current chapter reviews the evolutionary processes and hereditary mechanisms which resulted in the structure of the human body. We will see how our brain and nervous system transmit and interpret sensory information relaying it to parts of the body capable of responding. All of the inferences and conclusions drawn regarding how our internal processes enable us to adapt to our environment are based upon behavioral observations. At times you may wonder why so much detail is provided regarding human anatomy. You were expecting a course in psychology, not biology. I have done my best to emphasize those parts of the nervous system crucial to our survival and achievements as a species. We will start with a discussion of how human anatomy evolved.
Darwin’s Theory of Natural Sele