The stoned ape "theory" ("we owe our very existence as a species to psychedelics") isn't theory, despite it's pretense. There is no support for it in evidence, or in theory. Nor can there be because in its own terms it defies both. It's founder seems to have thought himself a genius, and solicited a cult-like following determined to spread his message, as their own. He had no college-level science education - see facts and citations below (*).
Bear in mind the "theorist's" target audience when he wrote Food of the Gods. Not scientists nor anyone scientifically literate. In his own words: "[The target audience is] the 18-25 year old group that is drug-friendly but has no rationale except that it's a good time" (Gracie, Zarkov & McKenna interview).
As for his understanding of evolution, the scope of his grasp, here's what he thought science says - if you believe what he says. No harm to have smelling salts in easy reach if you're minimally educated in biology, i.e. high school level:
"Conventional evolutionary theory tells us that small adaptive changes eventually become genetically scripted into the species" (OMNI interview)
Obviously that's 180 degrees backward from true or accurate, a recitation of what Lamarck thought - over 200 years ago, and before anyone ever heard of Darwin, or natural selection.
There's nothing theoretical in the "stoned apes" storyline, despite its claim. It's not a theory, its malarkey of the same type as Creationism - but from the opposite fringe: new age psychedelia, not old time religion.
*TM was at quite a disadvantage for science ed. For any major in college, even liberal arts - there's normally a 'general studies' science requirement. Its a minimal basic in higher ed, across the board. But TM's college program (Tussman Experimental) is one that specifically, uniquely excluded science. And short-lived as it was, the college was roundly criticized in its day on that very point. Its founder made excuses, e.g. this quote (from Tussman's book EXPERIMENT AT BERKELEY):
"It is recognized that the program does nothing in the way of integrating science with the social sciences and humanities. We leave this two-culture problem for wiser men to solve. In this respect, however, our students are either better OR WORSE OFF than others" (caps added for emphasis).
Obviously lame? Colleagues in education didn't buy it. For example, this remark from Sidney Rosen (Univ of Illinois): "By his admission that he cannot find a way of integrating scientific ideas into a basic two-year program, Mr. Tussman is guilty of contradicting the educational goals he defends ... It is difficult for me to see how the curriculum can flourish without science as an integral part." - Journal of Research in Science Teaching 7: 271 (1970)
Prescient? The college didn't flourish, it floundered. It was already crashing when Rosen wrote that. In fact, the 'experiment' seems to have perhaps been a case of politics in education, masquerading as 'educational reform.' TM himself offers an interesting remark along just such lines:
"... it was an experimental program... this thing called the Tussman Experimental College. I arrived at Berkeley the year after the Free Speech Movement ... in an effort to keep the place from blowing sky high they had told this left-wing professor that he could have an experimental section of the university" (www.tripzine.com/listing.php?id=terence1)
This is the kind of info those who think they're all into McKenna, all about his rap and 'ideas' - have no clue. Zero, none. Knowing anything whatsoever, that's able to be factually established, double-checked and verified as true and accurate, valid - ain't its ticket.