Oleanane
Encyclopedia
Oleanane is a natural triterpene
Triterpene
Triterpenes are terpenes consisting of six isoprene units and have the molecular formula C30H48.The pentacyclic triterpenes can be classified into lupane, oleanane or ursane groups.Animal- and plant-derived triterpenes exist, such as:*squalene...

. It forms the central core for a wide variety of chemical compounds found in flowering plants which are referred to collectively as oleanane triterpenes.

Some oleanane triterpenes have a suppressing effect on insect pests. They are considered a key marker differentiating flowering plants from other life, and have been used in the effort to study their 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...

, which is as of yet poorly documented in the fossil record.

These compounds appear to have been shared by a group of plants called gigantopterid
Gigantopterid
Gigantopterids is the name given to fossils of a group of plants existing in the Late Permian, some . Gigantopterids were among the most advanced land plants of the Paleozoic and disappeared soon after the massive Permian–Triassic extinction event...

s, which lived twice as long ago as the oldest known flower fossils. They may have been close relatives of the flowering plants, moving the divergence of the flowering plant lineage back to more than 250 million years ago.

Oleanane has also been found in extant ferns, though in those it is suspected of being produced "from a biochemical pathway separate from that found in angiosperms" (via convergent evolution
Convergent evolution
Convergent evolution describes the acquisition of the same biological trait in unrelated lineages.The wing is a classic example of convergent evolution in action. Although their last common ancestor did not have wings, both birds and bats do, and are capable of powered flight. The wings are...

).
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