Emergent Properties of Biological Systems

When individual components in an environment come together to create distinct, collective and interactive properties and functions, the results are called emergent properties. These emergent properties do not and cannot manifest themselves unless an organism is looked at in its entirety. As such, emergent properties are at the intrinsic core of the entire science of systems biology.

A further elaboration of emergent properties deduces that the systems they form are called irreducible, since they cannot be fully comprehended when broken down into smaller segments, much in the way that a person would be unable to capture the essence of a book by reading individual words.

At the same time, the systems that are produced through emergence are also considered complex, in that they are unpredictable even to people who are experts in the nature of the individual components.

One reason for the development of emergent properties is that an increase in the number of interacting simple components will naturally bring about an exponentially greater probability of possible reactions. However, it should not be implied that volume inexorably leads to emergent behavior, since many interactions are negligible.

Systems Summary

In summary, systems are comprised of parts which interact. The interaction of these parts gives rise to new properties and functions which are key to the system. We call these new properties and functions "emergent properties". Because emergent properties are the result of interactions between the parts, they can not be attributed to any single parts of the system. This makes systems irreducible. A system is unlikely to be fully understood by taking it apart and studying each part on its own. (We cannot understand an author's message by studying individual words; we cannot appreciate a forest by looking at individual trees.) To understand systems, and to be able to fully understand a system's emergent properties, systems need be studied as a whole. This recognition that complex systems, especially life, are truly understood from knowledge of the interactions of their component parts is fundamental to systems biology and all the research at the Institute for Systems Biology.

Examples of Emergent Properties

Life itself is an example of a complex system. You might agree that life cannot be predicted simply by analyzing the chemicals and organic compounds that comprise the tissues and organs of which we are made. Rather, we can only hope to fully understand life in all its complexity by studying the interaction of all the parts that comprise each organism.

A broader example of emergent properties in biology is the combination of individual atoms to form molecules such as polypeptide chains, which in turn fold and refold to form proteins. These proteins, assuming their functional status from their spatial conformation, interact together to achieve higher biological functions and eventually create - organelles, cells, tissues, organs, organ systems, and living organisms.

With our growing understanding of the genetic constitution of all life forms, and how genes affect our form and function, modern biology increasingly focuses on how genes interact, along with how the chemical compounds (i.e., proteins) produced from genes also interact. The complexity of humankind´s genetic makeup (approximately 25,000 genes) plus the myriad of proteins produced from these genes, give rise to the extraordinary functions of human beings (remember, emergent properties), and the corresponding complexity of a human being as systems.