The basic premise is to measure fitness in a conceptually similar way to how we measure mass. To measure mass we can use a scale to compare the effect of gravity on a test object to an object with an agreed upon mass, or we can compare the test object’s resistance to acceleration as compared to an object with an agreed upon mass. These methods measure the ‘gravitational’ mass and ‘inertial mass’ respectively.
Gravitational Mass and Selection Fitness
Measuring an object’s gravitational mass requires a uniform gravitational field, e.g. the gravitational field at the surface of the earth. The gravitational field accelerates things based upon how massive they are: the more massive an object is the greater the force that the gravitational field exerts. To measure the mass of an object it is placed on one pan of a scale and pre-calibrated masses (objects of known mass) are placed on the other pan. When the two pans are level the test object has an equivalent mass to the calibrated masses because they have equivalent forces being applied to them by the gravitational field.
To measure fitness we require a similar experimental setup. First, a uniform gravitational field: according to the General Theory of Biological Relativity ecosystems create large natural selection fields. A uniform natural selection field requires an ecosystem free from disturbances which could skew the reproductive rates of the organisms. Secondly we would need organisms with a standard fitness. A suitable organism would be easily clonable and of a fitness that we suspect our test organism to be near. That organism’s fitness would be defined as one ‘biogram’ (or what you will). Lastly we would need to see how the organisms fair in the ecosystem. Their fitness will be proportional: if both proliferate (or die off) at the same rate, then their fitness will be equivalent, if one does much better than the other then it’s fitness will be proportionally higher.
Inertial Mass and Survival Fitness
Measuring an object’s inertial mass is measuring how resistant it is to acceleration as compared to how resistant to acceleration an object of known mass is. To measure inertial mass the test mass is attached to a spring clamped horizontally to a stable structure. The mass and spring are then pulled to one side and let oscillate back and forth: the more massive the object, the slower oscillations. The number of oscillations per unit of time can be compared to the oscillations per time of a known mass and thence the inertial mass can be calculated.
As above a controlled environment and an organism whose fitness is known (even if by definition) is needed. However the organisms need to be ‘accelerated’ for this measurement. According to the General Theory of Biological Relativity environmental conditions will dictate how a species changes over time. Therefore to ‘accelerate’ a species a changing environment is needed. Simply put: measuring ‘survival fitness’ is measuring how well an organism or species fairs in a changing environment. For example a plant that can survive in a wide range of temperatures will be fitter than one that requires a narrow temperature range. If a test plant proliferates and the benchmark organism withers under a temperature swing, the test organism has a greater fitness.