( ( When ( humans ( breed ( animals ( for ( a ( specific trait ) ) ) ) ) ) ) ( we ( ( call ( this ( artificial selection ) ) ) . ) ) )
(ROOT (S (SBAR (WHADVP (WRB When)) (S (NP (NNS humans)) (VP (VBP breed) (NP (NP (NNS animals)) (PP (IN for) (NP (DT a) (JJ specific) (NN trait))))))) (NP (PRP we)) (VP (VBP call) (NP (DT this) (JJ artificial) (NN selection))) (. .)))
When humans breed animals for a specific trait we call this  artificial selection.
(ROOT (S (NP (NNS Humans)) (VP (VBP create) (NP (NP (JJ different) (NNS breeds)) (PP (IN of) (NP (NP (NNS organisms)) (VP (VBG using) (NP (JJ artificial) (NN selection))))))) (. .)))