Scientists investigate the mysterious origin of flowering plants

A new study from the University of Bristol may have just revealed the origin of flowering plants, a puzzle that even Charles Darwin once attempted to solve. Darwin described the sudden appearance of flowering plants in the fossil record from relatively recent geological times as an “abominable mystery.” 

Scientists became even more perplexed after genomic testing showed that flowering plants emerged long before what has been indicated by the fossil record. 

The Bristol team has found evidence that flowering plants originated in the Jurassic or earlier, which is millions of years before their oldest undisputed fossil evidence. According to the researchers, the lack of older fossils may be explained simply by a low probability of fossilization and the rarity of early flowering plants.

“A diverse group of flowering plants had been living for a very long time shadowed by ferns and gymnosperms, which were dominating ancient ecosystems. This reminds me of how modern mammals lived for a long time laying low in the age of dinosaurs, before becoming a dominant component of modern faunas,” explained study lead author Dr. Daniele Silvestro.

Flowering plants are now the most abundant and diverse group of plants worldwide, but the earliest flowering plants were small and rare. The new research suggests that flowering plants existed for as many as 100 million years before they became dominant.

“While we do not expect our study to put an end to the debate about angiosperm origin, it does provide a strong motivation for what some consider a hunt for the snark – a Jurassic flowering plant,” said study co-author Professor Philip Donoghue. “Rather than a mythical artefact of genome-based analyses, Jurassic angiosperms are an expectation of our interpretation of the fossil record.”

For their investigation, the researchers used complex modeling to analyze a large global database of fossil occurrences. The database was compiled by Dr. Yaowu Xing and his team at the Xishuangbanna Tropical Botanical Garden based on more than 700 publications. 

A total of more than 15,000 fossil records included members of many plant groups such as palms, orchids, sunflowers, and peas.

“Scientific debate has long been polarized between palaeontologists who estimate the antiquity of angiosperms based on the age of the oldest fossils, versus molecular biologists who use this information to calibrate molecular evolution to geologic time,” explained study co-author Dr Christine Bacon. “Our study shows that these views are too simplistic; the fossil record has to be interpreted.”

“A literal reading of the fossil record cannot be used to estimate realistically the time of origin of a group. Instead, we had to develop new mathematical models and use computer simulations to solve this problem in a robust way.”

Even 140 years after Darwin’s conundrum about the origin of flowering plants, the debate has widely persisted.

“Understanding when flowering plants went from being an insignificant group into becoming the cornerstone of most terrestrial ecosystems shows us that nature is dynamic,” said study co-author Professor Alexandre Antonelli.

“The devastating human impact on climate and biodiversity could mean that the successful species in the future will be very different to the ones we are accustomed to now.”

The study is published in the journal Nature Ecology and Evolution.

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By Chrissy Sexton, Earth.com Staff Writer