So far in this course, you've looked at a couple of "migrations" - but none which involved so many people with such a long-term set of effects as that of the Bantu in Africa.
You will look at the Aryan "invasions" or "migrations" into the Indus River Valley in the next unit. While Aryan culture did in time become dominant in that region - bringing with it Sanskrit and Hindu religion - it took a very long time and so far as we know did not involve a displacement of local Harappan peoples by a new people.
And later in the course you will also read about Greek/Hellenistic culture moving south and east under Alexander and his successors. Again, the number of Greeks in this long enterprise was certainly fewer than 50,000 in total. But of course the expansion of Greek culture did not require Greeks in large numbers.
And in the unit on Byzantium and Islam, you will examine the rise of Islam and the Arab "invasions" of Persia and Byzantium and North Africa - again here there were not hundreds of thousands of Arabs who left their peninsula to invade in all directions.
You can click on the following link for an interesting video presentation on the Bantu Expansion in Sub-Saharan Africa. This one takes the approach of identifying the movement of language as a good way to track the movement of people and culture in the ancient world. When you get to the online page, click on the lower left corner "View the Video Online".
The BBC in England also has an excellent website on the Bantu Migrations, as one section of their archive on "The Story of Africa." There is much here that can help you with the written assignment for this unit.
You can see the orange lines from #3, the Bantu homeland, with movements to the south east and south. This map also shows the spread of Islam, black lines from #7 and #8 on the Arabian peninsula across North Africa, and also along the east African coast - see the segment in this unit on the emergence of Islam.