Before revision:  Answering this question requires a model that can first explain the emergence of evolvable units , namely, structures that (1) preserve themselves in time (2) self-reproduce and (3) can tolerate a certain amount of variation when reproducing.
After revision:  Answering this question requires a model that can first explain the emergence of evolvable units , namely, structures that (1) preserve themselves in time (2) self-reproduce and (3) tolerate a certain amount of variation when reproducing.