3 ms·

my take based on several such articles. 8-10M ago humans (big apes that we were back then) got the ability to metabolize alcohol, ie. all those plentiful of fer

by trhway 3y ago

my take based on several such articles. 8-10M ago humans (big apes that we were back then) got the ability to metabolize alcohol, ie. all those plentiful of fermenting/rotting fruit on the ground became food. That in particular allowed for less tree climbing, more walking on the floor. That, in particular for the purposes of self-defense and body calories storage - to more body mass - that in turn to less tree climbing, more walking (posture change, hands more "handy"). How far the walking? Well, about 2M ago (clocked by the divergent mutations in the tapeworm shared by hyenas and humans, and which has a lifecycle stage in antelope/gazelle) humans got additional powerful energy source - started to scavenge carcasses in savannah, ie. meat eating. That naturally led to the tools (more specifically - weapons) use - hyena has teeth, yet we had hands and the bones to be used as a weapon were right were so to speak. Sticks and stones would do to. Hyenas chances weren't good. Pack of hyenas - well, we were also walking the savannah not alone. So the tools(weapons) usage, pack/tribal organization, energetic food source - that all leads to brain development as well as enabled and improved by such a development. Other fermented foods, food storage and fire seems to be seemingly important points associated with improved tools, social organization and associated brain development.

staplers 3y ago
Very interesting theory. Do we know what types of fruits they would have been eating off the ground? Also wondering if alcohol metabolization can be traced in dna or similar to align this theory.
- trhway 3y ago
  yes, it is DNA tracing, for example (and note - "increasing terrestrialization"): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8308604/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8308604/ "Paleogenetic reconstruction of alcohol dehydrogenase genes across the hominid phylogeny indicates a dramatically enhanced catabolic capacity in one particular ADH (ADH4, as encoded by the ADH7 allele), starting at about 10 Mya [26]. ADH4, although only one of multiple ADH forms present in mammals, is found primarily in the mouth and digestive tract and thus effects the “first pass” at the digestion of ethanol. This enzyme became dramatically better at metabolizing ethanol following the phyletic split between the lineage leading to modern orangutans and to the other great apes, including ourselves. It thus correlates well with increasing terrestrialization among the African apes, possibly yielding greater access to fermenting fruit crops on the ground, and thus resulting in increased ethanol within the diet [26]. "

by trhway 3y ago

staplers 3y ago

Very interesting theory. Do we know what types of fruits they would have been eating off the ground? Also wondering if alcohol metabolization can be traced in dna or similar to align this theory.

trhway 3y ago
yes, it is DNA tracing, for example (and note - "increasing terrestrialization"): https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8308604/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8308604/ "Paleogenetic reconstruction of alcohol dehydrogenase genes across the hominid phylogeny indicates a dramatically enhanced catabolic capacity in one particular ADH (ADH4, as encoded by the ADH7 allele), starting at about 10 Mya [26]. ADH4, although only one of multiple ADH forms present in mammals, is found primarily in the mouth and digestive tract and thus effects the “first pass” at the digestion of ethanol. This enzyme became dramatically better at metabolizing ethanol following the phyletic split between the lineage leading to modern orangutans and to the other great apes, including ourselves. It thus correlates well with increasing terrestrialization among the African apes, possibly yielding greater access to fermenting fruit crops on the ground, and thus resulting in increased ethanol within the diet [26]. "