What you've described is a utilitarian system whereby anything is permitted, so long as it serves the purpose of "continuation of the species." However, even that apparently immutable standard is in fact highly subjective, as you'll quickly discover once you try to define "continuation."
Beyond that, the idea of "continuation of the species" pretty much does away with the idea of individual morality.
First, as members of "the species", we're rather like skin cells -- to live or die at the convenience of the group. But more to the point, the time scale for my choices extends generations into the future -- I can never even know the ultimate denoument of my choices. What seems like my right decision today may (1000 years from now) result in the extinction of my species.