Thesis #41 – Experimental strategies for the study of aging that involve the use of environments that are evolutionarily novel will systematically impair the scientific study of aging, as natural selection will not have previously fostered adaptation to such novel environments.
In thesis 40, my focus was on the problems created by the Viktor Frankenstein experimental methods of the cell and molecular biologists studying aging. It is my hope that you find this point relatively obvious by this point in your reading of the 55. Here, in thesis 41, I am turning to a more subtle problem, which is that of evolutionary novelty.
An experimenter may go to a great deal of trouble to supply a population of animals with benign conditions, and furthermore forswear the use of unnatural inbreeding and mutagenesis. But there may still be a problem facing their research: giving the study organism a novel environment.
Let’s make this simple. Let’s say that you are studying aging in cats. You have a large colony of these predatory felines, so many that there is relatively little inbreeding. You ensure that they are kept free of epidemic infection, and of course they are not subjected to competition with other predators, such as dogs, bears, or lions. But you feed them some type of cereal-based “chow,” without meat of any kind. This chow contains all the essential amino acids, vitamins, minerals, and carbon sources required to sustain mammalian life, as far as biochemists are concerned.
But it is still the “wrong” environment. Cats didn’t evolve to eat cereal-based chow. This cereal-based food will contain substances that cats don’t normally digest in much abundance, such as omega-6 fatty acids. Furthermore, the cat gut isn’t adapted to digesting cereals in large quantities. Instead, its gut is well-adapted to eating raw animal parts, from muscle to liver.
In this evolutionarily novel environment, cats will suffer an aberrant pattern of adaptation. When they are young, their standard mammalian adaptations to consuming milk may provide them with digestive enzymes and gastro-intestinal function sufficient to allow them to grow and reach sexual maturity while eating this chow. But as adults they will lose most of those functional capacities, and their gut will have developed in such a way that animal flesh will be its ideal food. From that point onward, a cohort of adult cats given such food in your research facility will suffer from BOTH progressive reduction in function arising from Hamiltonian aging AND progressive chronic impairment arising from life under conditions to which it was never adapted. There will thus be TWO sets of worsening pathophysiologies. Sorting them out will be an extremely daunting task, even for an accomplished biologist.
Instead, the better experiment would be to feed these cats their evolutionarily optimal mice and other small prey, particularly if these prey are live and need to be hunted. Of course it seems cruel to us, from the standpoint of the mice. But that is the way of life to which cats have adapted, not some industrial-grade chow.
Here is a link to an excellent site that expands on Michael’s comments on Cats and diet and I think offers a parallel for us – do we eat Human Chow?