The eldest son, down through history, was usually preeminent, and got the birthright.  But not always.

In the Book of Mormon Ammon was the leader among the four brothers, but I suspect that Aaron was the eldest.  He was the one selected by the people from among the sons of Mosiah to be king Mosiah's successor.  That indicates that he was the firstborn.

Similarly, the Old Testament gives us food for thought in its treatment of the sons of Noah.  Shem, Ham, and Japheth are named four times in Genesis chapters 5 through 10, and always named in that order.  Yet Japheth was the elder brother.  Japheth was born when Noah was 450 years old.  Shem was born 42 years later "of her who was the mother of Japheth."  (Moses 8:12).  That makes Shem and Japheth full brothers.  Ham was the youngest, being born eight years after Shem.  Apparently Ham had a different mother than did Shem and Japheth, or the writer wouldn't have made that comment about Shem's mother.

Ham was thus the half brother to Shem and Japheth.  He is always named second when they are listed together.  Why is Japheth, the eldest, listed last?  All three "walked with God."  (Moses 8:27).

The answer probably lies in the fact that Shem was such a stellar person, and had been selected by the Lord to be a prophet in his own right.  It is widely thought that Shem was Melchizedek.  Melchizedek was "king of Salem (Jerusalem): according to the Bible Dictionary, and "reigned under his father."  (Alma 13:18).  Melchizedek's father would have thus been Noah.

Interestingly Noah and Shem were both contemporaries of Abraham.  Noah died 58 years after Abraham's birth, and Shem outlived Noah by another 152 years.  Shem actually outlived Abraham by 35 years.  Abraham probably met Shem or Noah or both.  Abraham paid tithes to Melchizedek (Genesis 13:15), who was quite probably Shem , and Abraham received the Priesthood from Melchizedek and was ordained by him.  (D&C 84:14).

Abraham was the possessor of the records of the fathers.  (Abraham 1:31).  He probably got them from Noah or Shem.

Noah and his sons probably began their float trip from somewhere in what is now America.  What we now call the New World was actually the Old, being the first inhabited area.  The world at that point of time was apparently one land mass as indicated by the biblical statement that the earth was divided in the days of Peleg (Genesis 10:25; 11:16-19), Shem's 2nd great grandson.

One of the Lord's complaints about people before the Flood was that Shem's, Ham's, and Japheth's daughters "sold themselves" (Moses 8:14, 15) by marrying the wicked "sons of men."  Noah and his sons and their wives thus boarded the ark leaving behind their children and grandchildren.  How hard would that have been?

An apocryphal story relates that after the rains began, those aboard the ark could hear people outside pounding on the sides of the ark hoping to be let in.  Was that their children?  They had been warned, but gave no heed.  The ark lifted off without them.

Those aboard the ark were still of childbearing age.  It would be likely that they still had small children.  No mention is made of any survivors of the Flood other than those eight adults, but I suspect that there would have been some small children aboard the ark.  They aren't mentioned, but they would not have been left behind.

The rains continued 40 days, and "all the high hills, that were under the whole heavens, were covered."  (Genesis 7:19).  The earth, which is a living thing, was thus baptized by water.  Soon it will undergo its second baptism, this time by fire.

The ark was afloat for 150 days (Genesis 7:24), or five months, before it rested on Ararat.  (Gen. 8:4).  Everyone, and all the animals, stayed aboard the ark for a total of one year and ten days before the door was opened and everyone debarked.   If Ararat is the same mountain as that in present-day Turkey, then it is easy to see how Mesopotamia and Babylon became the center for the first post-diluvian civilization.  Mesopotamia is just south of Ararat in the area between the Tigris and Euphrates Rivers in present-day Iraq.

The earth was "filled with violence" (Gen. 6:11, 13) before the Flood, forcing the Lord to wipe out humanity and to start over.  But mankind's righteousness did not last long.  Just 100 years after the Flood, Ham's grandson, Nimrod, began the construction of a great tower at Babel.  "They had brick for stone, and slime (bitumen) for mortar."  (Gen. 11:3).  Nimrod's intent was to outsmart God by making a high place to which the people could retreat if God should decide to send another flood.  Never mind that God had promised to never again do so.

Abraham, the 10th from Noah, stated that his fathers (multiple generations) were idol worshipers.  (Abraham 1:5-6).  How amazing is that?  How frustrating that must have been for the Lord.  How gratifying, on the other hand, that there were faithful ones like Abraham and Lot.

At the time that the Tower of Babel was being constructed I calculate that the world population was about 20,000.  (That is my estimate if there were no small children aboard the ark, whose presence would have enabled a faster repopulation of the world.)  That small population would have lived fairly close together.

I suspect, though, that they probably largely lived as tribes based upon their descendancy from Shem, Ham, or Japheth.  Ham's descendants were black, having received their Canaanite blood from Ham's wife.  Shem's and Japheth's descendants would not have intermarried with them.  Ham's family probably lived separately.  Shem's and Japheth's families probably lived separately, too; and at least initially, brothers and sisters married one another rather than marrying cousins.

Noah gave patriarchal blessings to his sons.  (Gen. 9:25-27).  Ham's descendants were to be "a servant of servants."  Shem was given preeminence.  Japheth was to "dwell in the tents of Shem."  That possibly means that Shem's and Japheth's descendants might intermarry, but I think the families largely stayed separate.

In order to put an end to the senseless building of the Tower, the Lord decreed that there would be a confusion of tongues.  A warning went out that such would be the case.  Jared and his brother asked that their language and the language of their friends not be confounded.  Those 13 couples (Ether 6:16) and their children were allowed to continue speaking the pure Adamic tongue.  The rest dispersed hither and yon.  Were the other groups led by a prophet like the Jaredites were?

At this same time the Lord caused the earth to be divided.  Pangaea was broken up.  The Atlantic Ocean took its place in the great rift which opened between South America and Africa.  What a great earthquake that would have been!  Was it felt in Mesopotamia?  The people knew about the event because the Bible says it happened in the days of Peleg.  He was given that particular name because of that event, so it must have happened just before or just after his birth.  Dividing the land was necessary in order to preserve America for the people whom the Lord would send there.

The Jaredites set off for that land.  I'm presuming they were Shemites.  Noah, being very aged, probably stayed in Mesopotamia.  Shem (if he was Melchizedek) ended up at Jerusalem.  Shem's descendants were thus in three places:  Mesopotamia, Jerusalem, and America.

Ham's descendants went south as evidenced by the discovery and settlement of Egypt by his daughter (Abraham 1:21-24).  That is how the Blacks came to inhabit Africa.

I think Japheth's descendants went east, and populated India and China.  Japheth would thus be the father of the Oriental people.

Archaeology and science say there were four great ancient civilizations:  Mesopotamia (the oldest), the Indus River civilization in Pakistan and India (the largest), the Hwang He civilization along the Hwang He River in China, and the Nile Valley civilization in Africa.  It is thought that all but the Mesopotamian civilization began about 2,500 B.C.  That fits nicely with my estimate that the Tower of Babel and the confusion of tongues took place about 2244 B.C.

Archaeologists and science overlook the Jaredite civilization in America.  They call it the Olmec civilization, but don't know very much about it.  It, too, began at about this same time, and was probably the greatest and most advanced civilization of its time.  (Ether 1:43).

The families of Shem, Ham, and Japheth might have done some intermarrying, but their descendancy was reckoned along the male lines.  Shem had five sons, Ham had four, and Japheth had seven.  "These are the families of the sons of Noah, after their generations, in their nations, and by these were the nations divided in the earth after the flood."  (Gen. 10:32).

Present-day "scholars" doubt the existence of Abraham and Noah, discount the scriptures as worthless, and don't believe in the Flood and the confusion of tongues.  They thus overlook the best evidences of all as they try to sort out the world's history.  They also didn't formerly believe that South America and Africa could have been joined.  They laughed at Alfred Wegener when he first proposed that theory, but they now accept plate tectonics as a fact.

Time will vindicate the Bible and the Book of Mormon.  Are there other records forthcoming?  Shem's descendants gave us what we have.  Did Ham's and Japheth's descendants also keep records?

It will be exciting to see what the future brings.