We are not indigenous to this planet
The search for the link in Darwinian evolution is fruitless. It does not exist.
Information from the Andromedans is the best we have to date and is recorded in detail by Alex Collier in his book “Defend Sacred Ground”. It is out of print but is free to download on the computer. Learn that we are not native to this planet and may have been seeded here from another galaxy. Some of this originates from the Draco an ancient reptilian race who themselves relate their appearance in this galaxy as an old civilisation established in the piracy of space. Their arrival in the region of Ursa Minor caused the populations of those planets to leave unable to resist this more powerful enemy. They became the populations of the Pleiades, and around the star systems of Sirius and Orion.
When you start to learn the Galactic history from other civilisations with very ancient records there are things which strain our credulity and imagination. What becomes apparent is that many of them exist on a higher level of vibration of the material, still physical but different after millions of years . The earliest humans are said to have been in Ursa Minor for 40 million years. Draco claim to pre-exist and exerted the right to own everything long before and caused them to leave and settle in conveniently distant areas of the galaxy. Terran Humanity is said to be peculiar in having genes of different races, 22 in all. This presents an interesting situation of many racial types with their different life styles, This is rare, in all the alien societies contacted there is only one particular race .
The longer they continue to exist problems arise as the Genome becomes deficient in the face of changes in the material world. That is how it looks, some are dying out and they take our genes in tissue sampling and abduction of embryos trying to hybridise. Success has been achieved in union within human races on other planets. These hybrids walk freely among us unrecognised.