"So far there is no mechanism for an organism to grow wings when it previously had none ."
"Well , actually there is . Bat wings for example are one of the easier problems for evolution to solve ( we can even see potential transitional stages in other animals like the flying squirrel ) . The co-option of existing structures is the bread and butter of evolution . Now , if bats and birds had four legs and wings , that would be more of a head-scratcher ."
"So far there is no mechanism for an organism to grow wings when it previously had none"
"Well , actually there is"