From Chabad.org: The Levites are appointed to serve in the Tabernacle, guard its vessels and assist the priests with their Tabernacle duties. This honor originally belonged to the Israelite firstborns, who were “acquired” by G‑d when He spared them during the Plague of the Firstborn. This privilege was taken away from them when they participated in the sin of the Golden Calf — and given to the Levites.

This Aliya starts by saying that it will now list Aaron and Moshe’s descendants, and then goes on to list only Aaron’s children. If only listing Aaron’s children, why say you will list Moshe’s descendants? From this a famous lesson is learned that because Moshe taught Aaron’s children Torah, they were considered Moshe’s children as well. The idea that teaching a child is as important as having one is a profound concept that does not getting enough attention.