DrmDoc

Hello All, Here are other comments I've posted elsewhere that some of you may want to explore. Again, I welcome your thoughts: "This difference between cortical volume and interbrain size supports a distinction suggested by the relative factors effecting cortical evolution among species divergent from humanity. While researching brain evolution for a book I wrote a few years ago, it became clear to me that the cortical development among animals ancestral to humans might have been compelled by a disparity in their sensory acuity. In a nutshell, ancestral animals, akin to contemporary primates, may not have had the sensory acuity of the predators they likely encountered as the protection of their receding African rainforests surrendered to the perils of what may have been a rapidly expanding continental savannah. Consequently, our animal ancestors were probably compelled to reason beyond the limitation of their sensory to survive and compete against faster, stealthier, sensory superior animals. Some believe that the differences in diet (as suggested by fossil teeth evidence) influenced the differences they discovered in brain size between primitive co-existent primate families. While some early primates may have been herbivores, some researchers believed that our ancestral primates began to eat meat and that this steady diet of protein enhanced their brain development. What these researchers failed to consider is the amount of reasoning and brainpower essential to procuring and maintaining a diet of meat compared to that required to obtain leaves, nuts, and roots. Essentially, when our ancestral primates began to eat meat, they had to reason how to compete with other, more skilled meat-eating animals to safely procure and maintain a source of sustenance that probably resisted being that source vigorously. Foraging among the trees of what was once lush rainforests, early primates didn't need the degree of visual, olfactory, and auditory acuity required of animals living in the flat, open grasslands of early Africa. Emerging from a retreating forest to a predator fraught savannah, early primates were likely forced to adapt beyond their sensory limitations to survive. Without sensory capabilities comparable to their savannah contemporaries, the competition, danger, fluid and varying circumstances associated with obtaining meat probably compelled our primate ancestors' use of brainpower in ways not required by foraging. As we know, through contemporary brain study, sensory experience and learning stimulate brain growth and development. Rather than meat consumption itself, the mental demands associated with obtaining meat likely stimulated the larger brain developments we have found among the primates considered ancestral to humans. Consequently, our dependency on the sophisticated thought processes our primate ancestors evolved to survive distinguishes our larger cortical-to-interbrain size ratio over that of more sensory dependent animals—in my opinion."

Hello All, Below are comments I've posted in other forums regarding the nature of sleep. I welcome your thoughts: "If some of us do not know why we sleep, it is because we haven't examined how sleep may have evolved among sleeping species. Nearly every species enters a state of rest that could be interpreted as sleep. This suggests a common evolutionary advantage to the sleep process among sleeping species; i.e., we would not have sleeping species if sleep did not offer some survival advantage to ancestral species. When we examine the neurological components of sleep in most animals, we find that its various attributes arose at varying stages in neural evolution. Contemporary sleep processes in the human brain appear to be mediated by neurons in the literal hypothalamus. Further down the brainstem, other components of the sleep process appear to suggest an earlier evolutionary incarnation of sleep. During the earliy stages of sleep, the brain engages in diminishing activity until the onset of atonia, which is the lost of muscle elasticity. Interestingly, atonia can and does occur in animals without hypothalmic neural structure. This positions atonia as one of sleep's earliest incarnation because it appears to be mediated by neural structures earlier in the brain's evolution than that suggested by the hypothalamus. If the brain evolved from some earlier form, we should be able to find some footprint of that form, which we can trace back to some earlier point. Most researchers agree that the brainstem is a primitive component of our central nervous system. Of the brainstems components, the spinal brain (myelencephalon) appears to be the most primitive segment because it most closely resemble the notochord development we find in existant species of primitive animal life. When we examine the afferent neural systems of the spinal brain, we find those associated with feeding. This infers that ancestral animals at this stage in brain development engaged behaviors requiring the intake of nutrients. Although the efferents neural paths of the spinal brain suggests movement at this stage in earlier ancestral animals, movement most likely evolved with the evolution of the metencephalon where we find more sophistocated afferent neural systems associated with sound detection. The ability to detect sound suggests ancestral animals at the stage where they were orienting themselves either away from or towards sensory stimuli. Early spinal brained animals were probably not as mobile as later metencephlic animals. This suggested lack of mobility infers that these animals had to adopt a stratergy that allowed for survival in the absences of readily available nutrients. In some archeological literature, it has been suggested that the earliest forms of complex life where a combination of plant and animal. During the prolonged absence of sunlight or nutrients in their primodial sea, immobile animals that could suspend their need for sustainance likely had a survival advantage over those that could not. During the atonic stage of sleep, we find a suspension of muscle readiness with energy devotion to organs more critical to our survival. Atonia appears to be mediated by the metencephalon/myelencephalon brainstem segments. This suggests that the earliest components of sleep evolved as a means to sustain survival through periods of prolonged food privation. Although food privation is not a severe concern for some of us, our modern brain rest upon a primitive foundation that was dependent on the periodic suspension of activity to conserve energy for more vital physiological systems. In our brain develpment, evolution built upon its successful systems rather than replace those systems. Sleep evolved from a vestigial need that has become integral to how our contemporary brain functions."