Interpolation theory

:"This article is about Interpolation Theory in Biology. See also interpolation (mathematics), interpolation (music), interpolation (manuscripts) and interpolation (computer programming)".

The Interpolation Theory, also known as the Intercalation Theory or the Antithetic Theory, is a theory that attempts to explain the origin of the alternation of generations in plants. The Interpolation Theory suggests that the sporophyte generation progenated from a haploid, green algal thallus in which repeated mitotic cell divisions of a zygote produced an embryo retained on the thallus and gave rise to the diploid phase (sporophyte). Ensuing evolution caused the sporophyte to become increasingly complex, both oranographically and anatomically.

The Interpolation Theory was introduced by Celakovsky (1874) as the Antithetic Theory. Bower (1889) further developed this theory and renamed it the Interpolation Theory. The theory was later supported by Overton (1893), Scott (1896), Strasburger (1897), Williams (1904), and others.

The gradual evolution of an independent, sporophyte phase was viewed by Bower as being closely related to the transition from aquatic to terrestrial plant life on Earth. The supporters of the Interpolation Theory believe that the progenators of land plants were algal-like, and evolved for terrestrial life under water stresses. The oldest known fossils of land plants were discovered in the cores of boreholes in Oman. The cores contained sets of four connected spore cells, divided from one mother cell. These sets of four are referred to as tetrads. The tetrads were enveloped by the remains of the spore sac in which they were developed. Study of the spore wall indicates a relationship with the liverworts. The fossils have been dated around the Middle Ordovician and are about 475 million years old.

Evidence supporting this theory can be found in the life cycle of modern Bryophytes in which the sporophyte is physiologically dependent on the gametophyte. Competing theories include the Transformation theory, which was introduced as the Homologous theory by Celacovsky, and also renamed by Bower.

References

* Gifford, Ernest M. and Adriance S. Foster. "Morphology and Evolution of Vascular Plants, Third Edition". New York: W.H. Freeman and Company, 1988. 15-19.
* Sinha, A.K. and Anil Kumar. "Botany for Degree Students - Pteridophyta". S. Chand. 9-10.
* Taylor, Thomas N., Hans Kerp, and Hagen Hass. "Life History Biology of Early Land Plants: Deciphering the Gametophyte Phase". PNAS. 2005. vol 102. no 16.
* Chopra, R.N., P.K. Kumra. "Biology of Bryophytes". New Age International Publishers. 125.
* "How Plants Conquered the Land". Hans' Paleobotany Pages.