Adaptive evolution or not: cone receptors in the eye vs odor receptors


Vision Research Links Color Blindness To Eye Cells, Not Brain  September 20, 2012

Excerpt: ‘The problem, they determined, must be in the first stage of sight. This is how they refocused on the cone receptor cells in the eye itself.”

My comment: If the problematic receptors were involved in olfactory acuity and specificity, they could be linked directly from sensory input to hormone-secreting tissue in the hypothalamus (see below) of the mammalian brain. That’s what I did with olfactory/pheromonal input, which epigenetically alters intracellular signaling and stochastic gene expression. The alterations in gene expression include duplications that enable de novo olfactory receptor genes.

The epigenetic alterations in olfactory receptor genes are responsible for adaptive evolution in species from microbes to man. Thus, it is ridiculous to claim that we have evolved to become primarily visual creatures. That, as we can “see” in the results of the study reported above, is a misrepresentation of facts.

Unfortunately, that misrepresentation is commonly accepted among philosophers, theorists, et. al., who have little understanding of the basic principles of biology and levels of biological organization that link sensory input directly to hormones and behavior in species with an adaptively evolved brain.

Light on the Brain September 20, 2012 By Sabrina Richards

Excerpt: “…the hypothalamus is one of the oldest parts of the vertebrate brain… “It’s very possible that this is one of the oldest functions”—one that evolved in “non-visual organisms” that had no eyes but still needed to sense light.”

Olfactory/pheromonal input acts on intracellular signaling and stochastic gene expression to alter production of de novo odor receptors that transmit signals to the hypothalamus. This is how food odors and pheromones epigenetically effect the hormones that affect vertebrate behavior.  The effect on hormones and their affect on behavior is  due to adaptively evolved ecological, social, neurogenic, and socio-cognitive niche construction.

Ingestive behavior and social behavior are odor receptor-mediated in all species (not just those that are sensitive to light) as would be expected due to the common molecular biology of all species. There is no biologically based explanation of how photo-receptor driven behavior could evolve via the effects of light on the hypothalamus without the epigenetic effects of nutrient chemicals and pheromones. Microbes must eat and reproduce along an epigenetic continuum before a multicellular species can evolve a brain with a hypothalamus that senses light.



Author: James Kohl

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