Rocks that contain fossils of Rhynia also often contain fossils of Sciadophyton. We know that Rhynia was a sporophyte and that Sciadophyton was a gametophyte. Because they grew together, we suspect that they may be the two generations of a single species. If so, did Rhynia have an alternation of isomorphic or heteromorphic generations? Also, if this is true, evolution has caused one generation to become more complex, the other to become less complex. Which is which? Explain.