teleology in evolution
By Sy Garte
Biology is derived from and depends on the rules of chemistry, including equilibrium, reaction kinetics, catalysis, organic synthesis, hydrolysis, entropy, etc. However, biology is a form of chemistry not seen elsewhere on the planet. Biology has emergent properties that do not allow the rules of chemistry to fully explain the behavior of biological systems. Considering the fact of emergence, it stands to reason that biology also follows its own unique laws, and the reductionist temptation to dismiss the existence of purely biological laws is a philosophical and scientific error.
At first glance, the most important distinguishing feature of biological chemistry from non-biological chemistry is the degree of molecular and functional complexity found in living organisms. Several hundred growth factors, cyclins, kinases, molecular switches, cascade systems, recognition signals, signal transducers, receptors, and assorted other protein factors have been identified in just the two related fields of transcriptional regulation and cell growth control alone. All of these molecules interact in complex concentration-dependent ways with each other and with other factors. The same is true for energy conversion, homeostasis, reproduction, and all the other functional attributes of living cells. Add a higher level of physiological complexity for multicellular organisms, and we have further emergent properties that we can see in the life all around us.
Many modern biologists have rejected the reductionist view and devoted themselves to an exciting exploration of the way complexity and emergence can lead to major insights in biological theory, as the development and growth of the new field of systems biology demonstrates.
But it isn’t only the enormous degree of complexity that makes biology fundamentally different from the chemistry and physics from which it emerged. The distinguishing feature of biological entities is that there is no conservation law for life. Life may be created and destroyed. Living entities are formed from other living entities, and the destruction of life (death) is irreversible.
The biological non-conservation principle does not violate the physical laws of conservation, because when a biological entity dies, only its biological attributes are destroyed. The matter and energy of the organism are neither created nor destroyed but are conserved or transformed as required by the laws of physics.
The non-conservation principle (NCP) distinguishes life from all other forms of energy and matter and leads directly to some of the important laws and characteristics of biological systems. Physics and chemistry can describe the action of an enzyme or the flow of energy in a cell, but at higher levels of biological organization, physical and chemical laws are not of much use, and uniquely biological laws that take the NCP into account are required. The most important of these is evolution by natural selection, which is utterly dependent on the NCP. Without biological death, natural selection could not function. It is the requirement for death, as well as the requirement for inheritance of characteristics, that make evolution a biological construct, not directly applicable (except in very general analogies) to non-biological systems.
There are other non-living complex systems that emerge from physical and chemical interactions. A storm emerges from a particular set of circumstances involving temperature, humidity, pressure and wind, and some of these (like wind) are themselves emergent phenomena of more basic components (such as temperature gradients in the atmosphere). A storm, as a complex system, can be said to be born as a result of accidental configurations that occur together in the right place at the right time. The storm will last for some period (its “lifetime”), and then “die” as the factors that keep it in homeostasis either dissipate or change due to other random, accidental events. If conditions of temperature and other factors are right, a random collision between two molecules in the atmosphere or the ocean may lead to a chemical reaction, producing the “birth” of a new compound. That compound will also remain in existence until it is in turn degraded by further chemical interactions, hydrolysis, or decomposition.
However, while these systems share the features of complexity, emergence, and decomposition with life, they do not undergo natural selection, because they lack inheritance: they have no inherent informational content that is passed to progeny.
The death of organisms is not equally probable, and that fact allows for natural selection to occur. Because natural selection must (by definition) favor survival, biological creatures evolve with an automatic drive toward increased fitness for survival. Thus, creatures become better adapted to their environments, and new features arise.
For almost the whole history of our planet, new living forms have been created from other living forms. This process, which we call reproduction, is purposeful, and directed by specific biochemical processes. Every living entity on the earth today is the result of a goal-oriented process built into the normal functioning of all living creatures by billions of years of evolution by natural selection. The critical biochemical pathways that reflect the purposefulness of life are replication of the genetic information, reproduction of the organism, and translation of the genetic information into biological characteristics (the linkage between genotype and phenotype).
Each of these biochemical processes is highly purposeful because it does not occur at random, nor does it depend on accidental appearances of forces or material, but rather is well controlled and very specific in timing and outcome. The agent of these processes (as well as of all the other processes required for life, such as energy conversion, biochemical synthesis, and homeostasis) is the living organism itself. While this might appear to be a circular statement, it follows directly from the uniquely biological law of natural selection. Any preserved and inherited allele that leads to an increase in fitness will increase in frequency in the population.
Cells do not decide to improve themselves but rely on evolutionary processes to do so. This is unique to biology. No storm system cares if it dies out or does not give rise to another storm. But bacteria, oak trees, and dolphins do care. Not consciously, of course, but as life becomes more and more complex, we can begin to see an actual will to survive so that animals will flee predators, and parents will protect offspring. In other words, life operates with purpose – it is goal oriented. Daniel Dennett, the famous atheist philosopher, is also a proponent of biological teleology as shown in this quote: “The biosphere is utterly saturated with design, with purpose, with reasons.“
This is not what Aristotle had in mind with his Telos. It is an automatic, non-conscious form of purpose (sometimes called internal teleology or teleonomy), but it is still purpose, and to deny its existence in life forms is to completely deny one of the most fundamental principles of biology, a principle that follows directly from the NCP and from evolution by natural selection.
Sy Garte, Ph.D. in biochemistry, has been a Professor of Public Health and Environmental Health Sciences at three Universities, and recently retired from a senior administrative position at the NIH.
Dr. Garte is Vice President of the Washington DC Chapter of the ASA, and Editor-in-Chief of God and Nature. He blogs at www.thebookofworks.com.