In Tradition in the ethics of Aristotle and MacIntyre Christopher Luz explains what is menat by Arostotle’s metaphysical biology, and how MacIntyre adapts (or rejects) elements of this in his own teloeological ethic.  The majority of the book is available on this link.

http://books.google.co.uk/books?id=Z9RaG9ccs44C&pg=PA133&lpg=PA133&dq=aristotle’s+metaphysical+biology&source=bl&ots=oFBtwVrJud&sig=92s3OeEIMCGg2KgVhtyAFTVu5xY&hl=en&sa=X&ei=AY2_T5qaKIGa0QXu76TcCg&ved=0CHQQ6AEwBw#v=onepage&q=aristotle’s%20metaphysical%20biology&f=false