there is kind of an "apples and oranges" thing to your question.
Until you get into it.. most people consider surname etymology and genealogy to be the same thing. Not at all.
"Descent" would usually involve ancestry, or finding where YOU (as a person) comes from. YOU come from (1) your parents.. and mom is a Jones (insert your name) by marriage only. Every woman is traced by her birth name..not married name (but that is used for locating records in later life). Now, go to each grandparent, and remember, the women have birth names. By now, you have 4 last names to work, all different. Each generation backwards, you descend EQUALLY from all your ancestors. That is.. 8 gr grandparents, 16 gr gr grandparents.. so on.
THAT is genealogy... ALWAYS working back from yourself, and really, it is not a surname issue. Contrary to popular thinking.. all persons with a same name are not going to be related.
Now, to the origin (etymology) of a surname. Long ago, no one had last names..since they were not needed. They are an identifier..and came about when needed since the village had 4 men named John, and they had to have something to distinguish. Several sources were used.. sometimes physical attributes (the Little one, the Blond one); the occupation (John the Smith); relationships (John, the son of Thomas..Thomasson); or where they came from (John from London).
If there was more than one (black)Smith, or whatever, it did not mean that they were related.
The name Little PROBABLY came from exactly what it sounds like. It will not mean that there was only one Little man, and all persons with the name come from him.
So.. origin of a name is WAY WAY in the past, and can vary. If it is an "English" name that does not make the person English now. For one thing.. names are NOT limited to just one country of origin. Sometimes, people even work back in their family to find a long forgotten adoption.. thus, John Schmidt (whose real parents maybe came from Germany) got adopted by the Little family when his parents died. His ancestry is German, from his birth lineage. His name is from another source.
Just something to consider. If someone wants to know "descent", it involves all their ancestors, from today, back. Names don't really have all that much to do with it.