Consequences of Relativity in Evolutionary Biology
My recent articles have argued for a relativistic approach to aspects of biology. One consequence of relativism is that biology has spatial and temporal dimensions as in physics. Secondly it suggests a new definition of fitness and fitness’s relation to mutation. This new definition will suggest a measurement technique for fitness and defuse some of the objections to the idea of ‘survival of the fittest’. Lastly the question of evolutionary drift can be addressed.
In biology, as in physics, there are both temporal and spatial dimensions. The temporal dimension of biology is measured in terms of generations and the spatial dimensions are measured in terms of mutations. To describe the motion of a species, i.e. how a species is evolving, we do so by stating its velocity. Just as in physics we have velocity = meters per second, in biology we have velocity = mutations per generation. Each kind of mutation is analogous to a direction; changes in physical structures x, y and z are graphed just like directions x, y and z. Species move through this evolutionary space-time by reproducing.
Biological fitness is analogous to physical mass. Mass can be thought of as how much physical matter an object is made of. Fitness is then defined as how much evolutionary matter an object is made of: ‘evolutionary matter’ being that which contributes to the survival/reproduction of the organism.
The concept of survival is a more intuitive concept than fitness: it is easier to appreciate the survival skills of an animal that withstands an attack. Likewise weight is an easier concept to grasp than mass, and this analogous situation suggests a way to measure fitness: Mass is (still) defined in terms of a standard block of metal and something comparable will be needed in order to measure fitness. If we were able to clone a ‘standard’ organism, e.g. a bacterium, and a replicate a controlled environment, then we could compare its survival to various test bacteria under the same conditions. Comparative fitness could then be numerically evaluated on survival rates of the test organism versus the standard organism under controlled conditions.
Just as in relativistic physics in which changes in motion that approach the maximum velocity (the speed of light) cause an apparent increase to the mass, certain mutations can change the fitness of a particular organism. This happens when the mutations have an actual effect on the life-cycle of the organism.
Relativism provides a response to a common criticism of evolutionary biology. The criticism is that the concept of ‘survival of the fittest’ is either obviously false or trivial: If we deem whichever organisms survive to be the fittest then by definition the fittest always survive. Instead, if we do not measure the fitness based upon survival rates, then it is not always the fittest who survive. To avoid this, fitness is sometimes defined in terms of greater ability to solve environmental ‘design problems’ than other organisms. This solution is ineffective because the biggest ‘design problem’ is how to survive and reproduce. However, since relative fitness can only be appraised with respect to an arbitrary standard in a controlled environment (and not survival rates in the wild) the circularity/trivialization argument does not apply.
Finally, evolutionary drift: Evolutionary drift is an increase of a trait in a population that apparently neither contributes to nor damages the population’s fitness; the trait has seemingly just ‘drifted’ into prominence. The question is how to distinguish between natural selection and this random drift.
Under biological relativity we can translate this question into physical terms: which is moving, the earth or the sun? According to relativity, depending on your point of reference, one, the other or both can be in motion at any point. With the sun judged to be immobile at the center of the solar system, the earth is in motion. In a geocentric view of the universe the earth is stable and the sun is moving. Based upon a view from a neighboring star, both the earth and the sun are moving. In the same vein we cannot tell the difference between drift and natural selection without specifying a specific reference point. Choosing this reference will inherently bias our view of the trait in favor of drift or natural selection, but this is a direct result of relativity and is nothing problematic.
Natural selection has to do with fitness, which depends upon specific traits, but is not depend completely upon individual traits. Some traits don’t have an appreciable affect on the fitness of an organism just as teeny bits of mass evaporating and condensing on a a block of metal have no appreciable affect on the overall mass of a piece of metal. Drift is just like this evaporation and condensation process. At any given point a group of organisms may take or lose some traits that have no appreciable affect on their fitness. To determine if a trait has increased the fitness of an organism or if it is the product of drift (no appreciable change), a comparison test as described in Measuring Fitness is all that is necessary.
GROUNDREPORT CONTACT LINK DOES NOT WORK
contact: noahgreenstein at noahgreenstein dot com
Tags: Relativity , Biology , Physics , Evolution
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.