“…it is almost as if the vegetal world assigned certain plants to be the diplomats and teachers to our young confused species, to help put us on a different path than the one we have chosen, racing to ecological decimation and self-extinction. How else to explain the consistent messages received in mushroom, ayahuasca, iboga, and peyote visions of a world out of balance, of the need to take responsibility, of the vast empathic sentience of the Gaian Mind? …In the same way that we garden plants, teacher plants like ayahuasca seem to garden us when we digest them” 
That our indigenous ancestors were more connected to the earth than we are is not up for debate. Also up for little debate is that the destruction of our environment is increasing at an alarming rate, threatening the premature extinction of our species, due to the modern way of life in which humans live more on nature than with it. When we started believing we could control life, we in many ways lost touch with the innate wildness within ourselves and the world around us. Simply put, we became less human.
When the earth still existed as a luscious place, rich in great plant diversity and wild land, people were more conscious and aware of the interconnectedness of all life forms -and more importantly, perhaps, that “things” like plants are living, intelligent organisms. As a result, the earth flourished. Many attribute these enhanced levels of consciousness in which the world seemed more alive and people believed there was no separation between themselves and nature to the leap in consciousness provoked by psychedelic plants, long hailed as “visionary plants.”
In fact, sacred use of psychedelic mushrooms, in which they were worshiped as vehicles with divine messages imperative to the well-being of man, can be traced as far back as the late Neolithic age. Proof can be found at the Tassili Plateau in Southern Algeria. Tassili Plateau looks almost like a maze of some sort, made out of stone escarpments chiseled by the wind into numerous narrow perpendicular corridors decorated with rock paintings of shamans dancing with psychedelic mushrooms in their hands and sprouting from their bodies. The image of mushrooms sprouting from their bodies is often interpreted as a representation of their ability to enhance and emanate the spirit when ingested.
One of the more well-known theories regarding the historical role of psychedelics in evolution is Terrence McKenna’s Stone Ape theory. McKenna believed the evolutionary lineage of homo sapiens could be traced back to psychedelic mushrooms in the grasslands of Africa, claiming it acted as a “tremendous force for directing the evolution of human beings away from that of the anthropoid apes and toward the unique adaptation that we see as special human beings today.” 
Biochemical Relationship Between Psychedelic Plants And The Human Brain
“Why is there overlapping biochemistry between certain plants and human brains? One proposal is that there is an evolving niche, one that is necessitated by an ecosystem whose survival is threatened.” -Kim A. Dawson 
Further fueling the idea that psychedelic plants play an important ecological and evolutionary role is the fact that psychedelic plants contain psychoactive chemicals that are strikingly similar to those found in the human brain, enabling them to act as synergetic keys that dissolve illusions of separateness from the natural world and other life forms, thereby restoring biochemical unity. The entheogenic chemicals in psychedelic plants responsible for shifting a person’s consciousness to reveal their inextricable interconnectedness with nature are remarkably similar to ones found in the human brain, such as indoleamine neuro-hormones like serotonin and melatonin regulate states of consciousness.
Psychoactive chemicals, which were created millions of years ago before the existence of mankind, were generated by the serotonin molecule, making it of no surprise that they are serotonergic activators that influence the serotonin receptors in the neural networks of all life forms. However, they do not activate all serotonergic receptors. Rather, they activate selective receptors in the brain to produce specific effects in the neural networks. Although psychedelics, also known as “serotonergic neurognostics,” have an impact on various 5-HT receptors, they have the greatest impact on 5-HT2a receptors, which are found throughout the human body. Areas with high concentrations of 5-HT2a receptors, namely the gastrointestinal system, immune system, cardiovascular system, and the brain, are affected the most due to their intrinsic, overlapping biochemistry with the serotonergic activating nature of psychedelic plants. In the brain, the cerebral cortex, thalamus, hippocampus, amygdala, and olfactory bulb are strongly affected, leading to alterations in hippocampal processing of sensory data and learning, altered gene expression, and heightened visual processing. Essentially, sensory gating (discussed in this previous article on the doors of perception) is altered, allowing more sensory input to reach consciousness.
Although a large portion of modern day society holds negative views regarding the use of psychedelic plants, the significant overlapping biochemistry of psychedelic plants and the human brain makes it quite difficult to continue to adhere to the belief that they are harmful and should be avoided, much less that they hold no relevance to our existence and well-being. It is hard to fathom that their remarkably similar biochemistry is of no importance on an ecological scale. Clearly, we are not as “separate” from the natural world and plants, such as psychedelics, as we may have been led to believe.
The Sacred Science follows eight people from around the world, with varying physical and psychological illnesses, as they embark on a one-month healing journey into the heart of the Amazon jungle.
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"If “Survivor” was actually real and had stakes worth caring about, it would be what happens here, and “The Sacred Science” hopefully is merely one in a long line of exciting endeavors from this group." - Billy Okeefe, McClatchy Tribune