somatic
reality versus abstraction. It is organisms, whether single- or multi-cellular, that produce new organisms. As we will discuss in detail when we consider the origins of multicellular organisms, a cell within a multicellular organism normally cannot survive outside the organism nor can it produce a new organism - it depends upon cooperation with the other cells of the organism. In fact, each multicellular organism is an example of a cooperative, highly integrated social system. The cells of a typical multicellular organism are part of a social system in which most cells have given up their ability to reproduce a new organism; their future depends upon the reproductive success of the organism of which they are a part. It is the organisms success in generating new organisms that underlies evolutions selective mechanisms. Within the organism, the cells that give rise to the next generation of organism are known as germ cells, those that do not that is, the cells that die when the organism dies are known as somatic cells.47 All organisms in the modern world, and for apparently the last ~3.5-3.8 billion years, arise from a pre-existing organism or, in the case of sexually reproducing organisms, from the cooperation of two organisms, an example of social evolution that we will consider in greater detail in Chapter 4. We will also see that breakdowns in such social systems can lead to the death of the organism or the disruption of the social system. Cancer is the most obvious example of an anti-social behavior; in evolutionary terms, it can, initially, be rewarded more copies of the cancerous cell are produced but ultimately leads to the extinction of the cancer, and often the death of the organism within which the cancer occurs.48 This is because evolutionary mechanisms are not driven by long term outcomes, but only by immediate ones. Spontaneous generation and the origin of life The ubiquity of organisms raises obvious questions: how did life start and what led to all these different types of organisms? At one point, people believed that these two questions had a single answer, but we now recognize that they are really two quite distinct questions and their answers involve distinct mechanisms. An early view held by those who thought about such things was that supernatural processes were necessary to produced life in general and human beings in particular. The articulation of the Cell Theory and the Theory of Evolution by Natural Selection, which we will discuss in detail in the next chapter, together with an accumulation of data enables us to conclude quite persuasively that life had a single successful origin, that only natural processes were involved, and that various again natural evolutionary processes generated the diversity of life. But how did life itself originate? It used to be widely accepted that various types of organisms, such as flies, frogs, and even mice, could arise spontaneously, from non-living matter.49 Flies, for example, were thought to appear from rotting flesh and mice from wheat. If true, on-going spontaneous generation would have profound implications for our understanding of biological systems. For example,.