Submitted to: Encyclopedia of Life Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/14/2009
Publication Date: 1/15/2010
Publication URL: http://mrw.interscience.wiley.com/emrw/9780470015902/els/article/a0002038/current/abstract?hd=All,sheila&hd=All,mccormick
Citation: Boavida, L.C., Mccormick, S.M. 2010. Gametophyte and Sporophyte. Encyclopedia of Life Sciences. Online 1/15/2010. 10.1002/9780470015902.a0002038.pub2. Interpretive Summary: This encyclopedia entry reviews the life cycles of plants, from the gametophyte phase to the sporophyte phase.
Technical Abstract: All land plants are believed to have had their origin in a unicellular green algal ancestor. The major innovations in the evolution of early land plants from their primitive ancestors were, not surprisingly, adaptations that allowed plants to reproduce in the absence of water. Besides a more sophisticated and differentiated multicellular anatomy, the invention of new reproductive structures and strategies were fundamental for the success of terrestrial colonization. One of the key innovations in the life history of land plants was the emergence of a haplo-diplontic life cycle, in which an asexual diploid phase, the sporophyte, is predominant over a reduced and dependent sexual haploid phase, the gametophyte. Other evolutionary trends include a transition to a heterosporic life cycle, internalization of gametes within specialized gametophytes, development of a pollination mechanism independent of water for fertilization, and the invention of seeds, an efficient way of protecting and dispersing the developing embryos.