Clarence Larkin, in his monumental work, Dispensational Truth, believed that those living on the millennial earth would be taken at the close of the thousand years and placed on the New Earth still in their mortal bodies. Eventually they would move out among the stars and begin to populate the known universe. 
This was the premise of The Mortalis series, those living past the millennium in their flesh and blood bodies would colonize new worlds and the Ascended (those in their resurrected bodies) would lead the way for the others. The healing plant described in the series is actually the tree of life (Genesis 2:9; Revelation 22:2). 
The curse is lifted during the millennium, but eliminated in the New Heaven and New Earth. Therefore, during the millennium, and after, animal life would again become passive as before the flood. In the series, Marion and her group are moving ahead of the effects of the curse due to their FTL capabilities. Of course, in eternity the Scriptures teach there will be no conflict (Rev. 21:4). 
Hopefully this will tie up some of the loose ends many have noted that were not explained in the novels. It might be helpful to do some research on Christian eschatology which would explain some of these concepts. I'd be happy to provide more information concerning the series.