Understanding evolution, adaptation, and phenotype
January 19, 2013 | James Kohl
Free full text: Scott EC (2013) Front. Gene. 3:303. doi:10.3389/fgene.2012.00303
Excerpt: “The differential transmission of genes over time produces evolutionary change, and ultimately, with speciation, the branching of the tree of life.”
My comment: The differential transmission of genes depends on the availability of nutrients. The metabolism of nutrients to species-specific pheromones enables natural selection. Natural selection is for pheromones that signal nutrient-dependent species-specific reproductive fitness and genetic diversity, which are expressed in the phenotype of individuals of all species.
The reproduction of individuals is controlled by pheromones in all species. Nutrients and pheromones cause the epigenetic landscape to become the physical landscape of DNA via their epigenetic effects on intracellular signaling and stochastic gene expression. Suffice it to say that the molecular mechanisms involved are the same in all species that have adaptively evolved. Simply put, the bottom-up control of gene expression by the epigenetic effects of nutrients enables individual survival. The top-down control of reproduction by the epigenetic effects of species-specific pheromones is exemplified in species from microbes to man.
Thus, there is one way to get from gene expression to behavior and back. That way is nutrient chemical-dependent and pheromone-controlled. It is chemical ecology that enables life’s diversity. Understanding the concept of nutrient-chemical dependent pheromone-controlled phenotypic expression is the key to understanding evolution, adaptation, and phenotype. None of these three things can be understood outside the context of the basic principles of biology and levels of biological organization, which are required to epigenetically link sensory cause to gene activation, to ingestive behavior, to reproduction, and back. For example, in my model, “Olfaction and odor receptors provide a clear evolutionary trail that can be followed from unicellular organisms to insects to humans.”
This model for all evolved phenotypes requires Creation of the first cell. Subsequently, the availability of food determines the ability of the first cell to diversify and interact with the pheromone-controlled diversity of life that Creation of the first nutrient chemical-dependent cell enabled. At the advent of sexual reproduction in yeasts, for example, sexually dimorphic cell types develop due to differences in glucose uptake, and pheromones signal epigenetically determined sex differences in the MAT locus of genes.
Escape from this pervasive model of nutrient-dependent pheromone-controlled evolved adaptations, which are phenotypically expressed, may require a comparable model. Alternatively, there is the requirement for the ongoing belief in a theory of adaptive evolution that has not been scientifically supported by anything researchers have learned about molecular epigenetics. In the context of that theory, belief, and disbelief, others have addressed the comparatively weak mentalizing abilities of people that “…render the representation of personified divine beings unintuitive.”