Thanks Dennis for this valuable contribution to this debate.
I agree that the same term ‘living nephesh’ (‘living creature’) in the immediate context of Genesis refers clearly and repeatedly to non-human animals: these and ‘Adam’ are made from the dust of the ground, and are each a ‘living nephesh’. “It is not man’s possession of ‘the breath of life’ or his status as a ‘living creature’ that differentiates him from the animals”. [Wenham, G.J. 198, p. 102]. Thus Genesis 2:7 can be read in correspondence to the gradual appearance of the species Homo sapiens in Africa, that is, “with a time depth that stretches back into the middle Pleistocene” (about 500,000 years ago) [Stringer C. 2016], very much like you suggest.
Nonetheless the term for humans being created in the Image of God, as male and female (Genesis 1:27) called to respect the commandment: “What God has joined together, man must never separate” (Genesis 2:24, Matthew 19:4-6, and Mark 10:6-9) is not applied to non-human animals, and refers to a sharp beginning of “humans as spiritual beings”.
So one can’t help acknowledging “as theologically mandated by Genesis” that at certain moment God made the “nephesh” (Genesis 2:7) to an Image Bearer (Genesis 1:27 and Genesis 2:24) called to freely love God, with sense of law, and capability to sin. Since this divine intervention happened at the spiritual level there is obviously no observable biological (genetic or anatomical) discontinuity.
In my view it is the option Jesus Christ takes by resolutely calling himself “the Son of Man”.
Actually it is God’s Incarnation which defines the specific body God wants for “His visible Image” Jesus Christ (Colossians 1:15) and thereby establishes the precise moment in human evolution when He considers this body prepared to be made “in God’s Image” (Genesis 1:27).
That “humans have a punctuate theological beginning” seems to me also supported by Luke’s Genealogy of Jesus (Luke 3:23-38), going back generation by generation to Adam, with a precise list of 76 generations, and calling Adam “Son of God” in the end (Luke 3:38).
The sharp beginning of Humanity as the community of Image Bearers through an act of God seems to be “theologically mandated by Genesis” according to the teaching of Jesus Christ.
So, if you don’t want to jeopardize the meaning of Incarnation and Redemption it is wise to keep in mind: