Usage of "select"

Hi,

I was wondering if this senetence is grammatical, in terms of usage of "select" :

"Instead, people created a new environment for them, and selected for other
characteristics than nature previously had.
Seeds recovered at archaeological sites clearly show that farmers selected for larger
seeds and thinner seed coats."


I think the verb 'select' has "object" ( other characteristics / larger seeds and thinner seed coats)
therefore preposition "for" should be deleted.

-----> People selected for other characteristics. (x)
People selected other characteristics. (o)
Farmers selected for seeds and thinner seed coats. (x)
Farmers selected seeds and thinner seed coats. (o)

Am I right or wrong?

Hungry for your replies,

Good Day!
TTiger