Interpolation theory
Encyclopedia
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 Čelakovský
(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 progenitors 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 Čelakovský, and also renamed by Bower.
Alternation of generations
Alternation of generations is a term primarily used in describing the life cycle of plants . A multicellular sporophyte, which is diploid with 2N paired chromosomes , alternates with a multicellular gametophyte, which is haploid with N unpaired chromosomes...
in plants. The Interpolation Theory suggests that the sporophyte
Sporophyte
All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or algae that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants...
generation progenated from a haploid, green algal thallus in which repeated mitotic cell divisions of a zygote
Zygote
A zygote , or zygocyte, is the initial cell formed when two gamete cells are joined by means of sexual reproduction. In multicellular organisms, it is the earliest developmental stage of the embryo...
produced an embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
retained on the thallus and gave rise to the diploid phase (sporophyte
Sporophyte
All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or algae that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants...
). Ensuing evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
caused the sporophyte
Sporophyte
All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or algae that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants...
to become increasingly complex, both oranographically and anatomically.
The Interpolation Theory was introduced by Čelakovský
Ladislav Josef Celakovský
Ladislav Josef Čelakovský was a Czech botanist who was born in Prague. He was the son of writer František Ladislav Čelakovský, and father to mycologist Ladislav František Čelakovský ....
(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
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
of an independent, sporophyte
Sporophyte
All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or algae that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants...
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 progenitors 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
Oman
Oman , officially called the Sultanate of Oman , is an Arab state in southwest Asia on the southeast coast of the Arabian Peninsula. It is bordered by the United Arab Emirates to the northwest, Saudi Arabia to the west, and Yemen to the southwest. The coast is formed by the Arabian Sea on the...
. The cores contained sets of four connected spore
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
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
Spore
In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...
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
Ordovician
The Ordovician is a geologic period and system, the second of six of the Paleozoic Era, and covers the time between 488.3±1.7 to 443.7±1.5 million years ago . It follows the Cambrian Period and is followed by the Silurian Period...
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
Sporophyte
All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or algae that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants...
is physiologically dependent on the gametophyte
Gametophyte
A gametophyte is the haploid, multicellular phase of plants and algae that undergo alternation of generations, with each of its cells containing only a single set of chromosomes....
. Competing theories include the Transformation theory, which was introduced as the Homologous theory by Čelakovský, and also renamed by Bower.