Why does Genesis 1 speak of "the evening & the morning were the nth day" instead of "the evening & the ....?

The Hebrews amongst others believed that the first half of a day started in the evening - sunset, and that the second half went from sunrise to the descent of the Sun. This equals one day, Leviticus 23:32. Morning here stands in for the whole period of daylight. Other than Kabbalists who mystify everything, what "scholars" make poetic this concept. The morning Mincha happened at dawn, and the evening one occured at about three p.m.. Also, while the Lord uses 'types and shadows' / representations, in His word, where is the connection between the creation week and two times of Israeli prayer?