What Earth's First Flower Might Have Looked Like

Geronimo Vena
Agosto 3, 2017

For instance, the reconstruction shows how the ancient flower differed from its numerous modern descendants. Among the most surprising results from the project is a new model of an original ancestral flower that does not match any of the ideas proposed previously - shedding new light on the early evolution of flowers as well as major patterns in floral evolution across all living flowering plants.

"However, several essential aspects of the ancestral flower have so far remained unresolved, due to particularly confounding variation in floral structure among the earliest diverging lineages of angiosperms".

"We nearly know nothing about how flowers evolved since their origin and yet this is extremely important for their ecological role and the role that plants play today on Earth", said Hervé Sauquet, an evolutionary biologist and first author of the new study from Paris-Sud University. This study is important as it tells us how complicated the ancestral flower is likely to be - now the search is on to find it or something closely resembling it in the fossil record. These are the main characteristics of the first flowers to appear on Earth between 250 and 140 million years ago, according to research published on Tuesday in the journal Nature Communications.

The study saw an unprecedented global effort to combine information on the structure of flowers with the latest information on the evolutionary tree of flowering plants based on DNA.

The researchers wrote: "In spite of similarities with some extant (present day) flowers, there is no living species that shares this exact combination of characters". We don't know for sure what colour this flower would have been, but I think it is quite pretty'. Combined sexes can be advantageous when colonizing new environments as a single individual can be its own mate, and indeed many plant species colonizing remote oceanic islands tend to be hermaphrodite.

That, says Sauquet, overturns a long held idea that such structures in early flowers had a spiral arrangement which gave way to the whorled configuration that is prevalent today.

The study also reveals that the ancestral flower's stamens, petals and sepals - protective petal-like parts - were arranged not in spirals but concentric circles called whorls, with three petals or sepals in each. The early flower had more numerous whorls, however, suggesting flowers have become simpler over time.

"But we don't know yet what that ancestor looked like, nor what happened in between these two ancestors, a period of time some of us like to refer to as a 'dark tunnel, '" Sauquet said.

The fewer layers are believed to have evolved to allow plants to develop more interestingly shaped petals. The detailed steps leading to its evolution are unknown.

The oldest-known fossils of flowering plants date from about 140 million years ago - during the age of the dinosaurs which went extinct some 66 million years ago.

Mario Vallejo-Marin is an associate professor in evolutionary biology at the University of Stirling.

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