<b>Complex Systems</b><br><i>Biology’s First Law</i>

Speaker: Dan McShea (Duke University)

In modern evolutionary theory, natural selection explains adaptation, the fit of organisms to their environments, but what explains complexity? What explains the fact that modern organisms consist of many different part types, while ancient organisms were simpler? Drawing on recent work with my colleague Robert Brandon (Philosophy, Duke), I argue that there is a spontaneous tendency for parts in organisms to differentiate, a tendency that does not depend on natural selection and could in principle be opposed by selection. This tendency is predicted by what we call the Zero Force Evolutionary Law, or ZFEL. The law is analogous to Newton’s First Law in that it tells us what to expect when no forces act. Newton’s First Law says that when no forces act, velocities remain unchanged. The ZFEL says that when no forces act, complexity tends to increase. In this talk, I will:

1. explain the logic behind the ZFEL;
2. argue that the ZFEL applies universally, to life at all times, everywhere it occurs;
3. defend the understanding of complexity on which the law is based;
4. offer a simple empirical test; and
5. show how the ZFEL points to a new way to understand the history of complexity change in evolution.