Year Zero begins when God “formed” Adam of the dust of the ground and breathed into Adam’s nostrils and Adam became a living soul. Gen. 2:7
Prior to the fall of Adam there was no death (not even in the animal kingdom). Man, beast, and fowl only ate plant life. Gen. 1:29-30
During this period there was no rain, but rather there went up a mist from the earth, and watered the whole face of the ground. Gen. 2:6
God institutes marriage with the formation of Eve from one of Adam’s ribs. Gen. 2:18, 21-25
The date of the fall of Adam is not specified but with it sin and death came upon all of creation (including in the animal kingdom); the woman was made subject to her husband, her desires was to be to her husband, the ground was cursed and brought up thorns and thistles; and man was made to work for his daily bread and all flesh would now return unto the dust from whence it came. Gen. 2-3.
Prophesy of the coming Messiah given to Adam. Gen. 2:14-15.
Animal sacrifice was implicitly established by God himself when he made coats of skins and clothed Adam and Eve in them. Gen. 3:21.
Adam driven out of the garden of Eden and made “to till the ground”. Gen. 3:23-24. You can see that animal husbandry and farming were from the beginning as Abel was a shepherd and Cain a farmer. Gen. 4:2-7.
Musical instruments, including the harp and the organ, were established during this time period because Jubal, the 5th from Cain, was the father of all such as handle the harp and organ). Gen. 4:16-21.
Metal working in brass and iron was established in this time period as Tubalcain, a brother of Jubal’s and therefore also in the 5th generation from Cain was an “instructor of every artificer in brass and iron.” Gen. 4:22.
Enoch, the 7th from Adam, was a contemporary of Adam for 308 years and was “translated” for “God took him” a scant 57 years after Adam’s death. Gen. 5:21-24.
During Enoch’s life, he prophesied saying “Behold, the Lord cometh with ten thousands of his saints, to execute judgment upon all, and to convince all that are ungodly among them of all their ungodly deeds which they have ungodly committed, and of all their hard speeches which ungodly sinners have spoken against him.” Jude 1:14-15.
Enoch was translated before Adam’s son Seth (the 2nd from Adam) or the next 4 generations of Adam’s named progeny died.
Methuselah, who was Enoch’s son, was Noah’s grandfather and died in the year of the flood.
